From Yeast to Therapeutics: Modeling Neurodegenerative Diseases in S. cerevisiae

Here we review the use of Saccharomyces cerevisiae as a powerful model organism for studying cellular processes implicated in neurodegenerative disorders, including stress responses, proteostasis impairment, and vesicle trafficking defects. Over the last two decades, baker’s yeast models have been developed for complex diseases such as Parkinson’s, Alzheimer’s, Huntington’s, and Amyotrophic Lateral Sclerosis (ALS). Yeast cells expressing human proteins like amyloid-β, α-synuclein, huntingtin, and TDP-43 have become crucial tools for high-throughput drug screening aimed at counteracting disease progression. These yeast models have unveiled key components involved in the metabolism and toxicity of these proteins, enabling the identification of interacting partners and novel factors within each pathway. Importantly, these pathways were subsequently shown to be conserved in mammalian models. Furthermore, drug candidates identified using yeast models have provided significant leads for drug discovery, highlighting their potential for developing treatments for these neurodegenerative diseases. From Yeast to Therapeutics: Modeling Neurodegenerative Diseases in S. cerevisiae Jose Ribamar Ferreira-Junior 1, Vittoria de Lima Camandona 1, Mario H. Barros 2 .1- Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brazil.2- Instituto Ciências Biomédicas - Universidade de São Paulo, Departamento Microbiologia, Sao Paulo, Brazil.Correspondence address: Mario H. Barros, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Professor Lineu Prestes, 1374, 05508-900, São Paulo, Brazil; email: [email protected] title: Yeast in Neurodegeneration ResearchKeywordsMolecular Neuroscience; Molecular Biology; Biological Process; Genetics; PhysiologyAbstractHere we review the use of Saccharomyces cerevisiae as a powerful model organism for studying cellular processes implicated in neurodegenerative disorders, including stress responses, proteostasis impairment, and vesicle trafficking defects. Over the last two decades, baker’s yeast models have been developed for complex diseases such as Parkinson’s, Alzheimer’s, Huntington’s, and Amyotrophic Lateral Sclerosis (ALS). Yeast cells expressing human proteins like amyloid-β, α-synuclein, huntingtin, and TDP-43 have become crucial tools for high-throughput drug screening aimed at counteracting disease progression. These yeast models have unveiled key components involved in the metabolism and toxicity of these proteins, enabling the identification of interacting partners and novel factors within each pathway. Importantly, these pathways were subsequently shown to be conserved in mammalian models. Furthermore, drug candidates identified using yeast models have provided significant leads for drug discovery, highlighting their potential for developing treatments for these neurodegenerative diseases.Protein misfolding and trafficking dysfunction are primary drivers of pathology in neurodegenerative diseases. Studying these inherently complex processes in neurons is challenging, but simpler cellular models like yeast offer a powerful alternative. Although it is impossible to study all different aspects underlying neurodegenerative diseases in unicellular organisms, aspects that precipitate protein pathologies can be easily studied in yeast. Basic cell processes that control protein-folding homeostasis are highly conserved and the lack of intercellular connections eliminates complexity, providing a focus on the basic protein conformation dynamics.For instance, key mechanisms are shared between yeast and neurons: chaperones in neurons and yeast interact with highly reactive proteins in their folding process, preventing inappropriate interactions during folding; protein remodeling factors can prevent and reverse protein aggregation; the proteasome degrades by proteolysis damaged or misfolded proteins; and in autophagic processes, cells remove unnecessary or dysfunctional components, including entire organelles. Vesicular trafficking is also conserved. In yeast cells, the secretory pathway and vesicular trafficking are responsible for molecular traffic between specific membrane-enclosed compartments around the cell in a highly orchestrated way for mating pheromones transport, receptor trafficking, and cell wall components deposition. Likewise, neurons vesicle trafficking manages neurotransmitters, neurotrophic factors, and extracellular matrix deposition create a microenvironment that modulates neuron function. Neurons and yeast have the same organelles, including RE, Golgi, lysosomes, peroxisomes, and mitochondria. Both cell types share quality control pathways, including autophagy and apoptosis, and signaling transduction pathways that have been preserved during evolution, including AMPK, calcineurin, and TOR (Dhakal and Macreadie, 2020). Therefore, it is possible to model the unique, multifaceted toxicities of different proteins at the cellular level using yeast, but it requires a careful experimental design considering the slow development of neurodegenerative proteotoxicity during aging (Ruetenik and Barrientos, 2018; Jiang and MacNeil, 2023; Stella et al, 2025). Saccharomyces cerevisiae biology has been studied for the last one hundred years, favored by its simplicity, low cost, and industrial importance in baking and brewing. Researchers have employed yeast as a tool to study every aspect of cell biology. In molecular biology studies yeast is an unrivaled tool kit, it includes a compact genome, versatile grow as a haploid, or diploid, unparalleled genetics facilities, an extensively studied DNA transformation system, and in the post-genomic era the possibility of high-throughput screens using comprehensive gene knockout collections. At least a dozen of Nobel prizes studies were sustained and developed based on the so-called awesome power of yeast genetics; in the current century, Hartwell work on Key Regulator of Cell Cycle (2001), Scheckman in the secretory pathway (2013) and Ohsumi in the mechanism of Autophagy (2016) are among the laureates. Such seminal works in yeast have been fundamental to understanding the physiology of our cells and the pathophysiology of human diseases, particularly neurodegenerative disorders.Building on foundational work by Susan Lindquist and others, Saccharomyces cerevisiae has emerged as a powerful model for studying protein misfolding and trafficking defects in age-related neurodegenerative disorders (Khurana et al., 2017) . Notably, yeast prions share molecular properties with amyloidogenic proteins implicated in neurodegenerative diseases (Lindquist, 1997). Prions and amyloid-forming proteins undergo conformational changes that template misfolding onto identical proteins, a process often facilitated by chaperones and remodeling factors like Hsp104p, involved in their propagation (Lindquist et al., 1998; Du et al., 2019; Ishikawa, 2021). Alzheimer, Parkinson, Huntington, amyotrophic lateral sclerosis (ALS), and gliomas have been linked to self-templating forms of specific amyloid deposits: Amyloid β and tau in Alzheimer, α-synuclein in Parkinson, huntingtin in Huntington, TDP-43 in ALS, and GLIPR2 in gliomas. Lindquist’s seminal approach involved expressing these human amyloidogenic proteins in yeast, which successfully recapitulated core cytotoxic features observed in patients (Treusch et al., 2011); yeast cells expressing human Aβ (Matlack et al., 2014), α-synuclein, huntingtin, TDP-43 (Tardiff et al., 2013), and GLIPR2 ( Tardiff et al., 2012) became crucial for unbiased drug search in high throughput genetic screens for these devastating illness.Unveiling particular molecular aspects of human neurodegenerative diseases in yeast models depends on genetic and physiological constraints, such as the presence or absence, of disease-genes orthologs in the yeast genome. In this conservative scenario, functional complementation studies promptly figure whether the human disease gene product replaces the function of the yeast gene product. However, in some neurodegenerative diseases, the disease-associated genes do not have a yeast ortholog, but a gain of function of the disease mutant proteins greatly contributed to pathogenicity and can still be investigated in yeast through heterologous expression (Jiang and MacNeil, 2023; Ruetenik & Barrientos, 2018; Menezes et al., 2015). Notably, research in the fission yeast Schizosaccharomyces pombe model has uncovered that some prion-like disease-associated proteins can paradoxically confer cellular protection by indirectly upregulating stress response pathways (Marte et al., 2022).Neurodegenerative disorders1- Parkinson’s diseaseParkinson’s disease (PD) is a neurodegenerative disorder that affects predominately dopamine-producing neurons. It affects people over 60 years old, but early-onset occurs in 10 to 14 percent of cases. The main symptoms are tremor, slow movement, muscle stiffness, swallowing problems, speech disorder, and cognitive impairment; as the disease progresses the symptoms get worse over time. The identification of genetic determinants of PD allowed extensive studies toward the understanding of molecular mechanisms, and yeast models have been fundamental in this process based on the heterologous expression of the human genes SNCA, SNCAIP, PINK1, PARK2, PARK8; or by studying the function and pathological role of the yeast counterparts genes for PARK7, VPS35(PARK17), ATP13A2 (PARK9), and EIF4G1 (PARK18) (Surguchov, 2021; Menezes et al., 2015). SNCA expression and α-synuclein aggregation will be better detailed after a summary of other PD genetic determinants.PARK7 codes for the multifunctional protein DJ-1, which in yeast has four conserved homologs: Hsp31, Hsp32, Hsp33, and Hsp34. DJ-1 inhibits α-synuclein aggregation and in yeast these proteins are needed for diauxic-shift reprogramming and cell survival in stationary phase (Miller-Fleming et al., 2014); as well as promote resistance to several stresses (Natkańska et al., 2017); upon redox stress, Hsp31p translocates to mitochondria, where DJ-1 paralogs regulate mitochondrial dynamics and ROS homeostasis (Bankapalli et al., 2020). Overexpression of DJ-1 or yeast counterparts reversed α-synuclein dependent cellular toxicity, and functionally complemented Hsp31, suppressing mitochondrial superoxide levels (Zondler et al., 2014; Bankapalli et al., 2015). VPS35 (PARK17) has been implicated in familial cases of PD (Menezes et al., 2015). As discussed later DJ-1 is also important in avoiding oligomerization of Aβ-42, tau, HTT and TDP-43 (Sajjad et al., 2014, Jana et al., 2023, Jimenez-Harrison et al., 2023).EIF4G1 (PARK18) is an autosomal dominant PD determinant gene and has two homologs in yeast: TIF4631 and TIF4632, which encode for the translation initiation factor eIF4G. Upregulation of eIF4G causes defects associated with protein misfolding (Dhungel et al., 2015). Yeast synthetic lethal screen for TIF4631 and VPS35 converged to a complex of proteins important in recycling transmembrane receptors from endosomes to the trans-Golgi network consisting of Vps26, Vps35, Vps29, Vps5, and Vps17 – the retromer, which orchestrates the intracellular sorting of thousands of integral membrane proteins and, therefore, essential for α-synuclein toxicity (Dhungel et al., 2015; Simonetti and Cullen, 2018). Indeed, early studies in yeast showed Vps35p participation in vesicle-trafficking modulating α-synuclein cytotoxicity (Tardiff et al., 2013).ATP13A2 (PARK9) encodes for lysosomal P-type ATPase, while the yeast counterpart YPK9 encodes a vacuolar transporter with a possible role in sequestering divalent heavy metals, which are assumed environmental risk factors for PD; yeast YPK9 protect cells from manganese toxicity and α-synuclein cytotoxicity. Gitler et al. demonstrated that the protective role of Ypk9 against α-synuclein toxicity is conserved across species, and that overexpression of the mammalian PARK9 gene can mitigate α-synuclein–induced neurodegeneration in various animal models (Gitler et al., 2009; Yeger-Lotem, 2009).PARK8 encodes for LRKK2 (leucine-rich repeat kinase 2), mutations in LRKK2 are the most frequent genetic cause of PD. This gene has no counterpart in yeast, but LRRK2 heterologous expression leads to growth arrest and the separated expression of LRKK2 GTPase domain is toxic with impairments in endocytic vesicular trafficking, autophagy, and mitochondrial biogenesis in aging yeast (Xiong et al., 2010, Aufschnaiter et al., 2018).Finally, PARK2 encodes the protein Parkin, a 465-residue E3 ubiquitin ligase with a particular affinity to proteins in the mitochondrial outer membrane, where together with Pink1 control organelle quality by mitophagy (Seirafi et al., 2015). Parkin has no yeast homolog, but human Parkin expressed in yeast is also directed to mitochondria under oxidative stress, whereas it promotes mitophagy and extends life span (Pereira et al., 2015).Lewy body formation, driven by α-synuclein aggregation, is the pathological hallmark of α-synucleinopathies, including PD. Abnormal accumulation of α-synuclein leads to protein misfolding and aggregation, damaging multiple cellular structures and ultimately causing cell death, a central mechanism in disease pathogenesis. α-Synuclein is a 140-residue amphipathic protein encoded by the SNCA gene. Primarily expressed in the cerebral cortex system, it exhibits a strong affinity for phospholipids in cellular membranes (Jakes et al., 1994). N-terminus of α-synuclein contains KTKEGV repeats that mediate interactions with membrane phospholipids, promoting a shift from random coil to an α-helical conformation (Davidson et al., 1998). Its central region harbors the hydrophobic NAC domain, essential for fibrillization (Giasson et al., 2001). Consequently, α-synuclein can adopt an amphiphilic helix that binds the surface of synaptic vesicles. However, at high concentrations, membrane-bound α-synuclein can disrupt lipid membranes or assemble into β-sheet-rich aggregates. These prion-like aggregates propagate misfolding and ultimately form Lewy bodies, leading to neuronal cell death (Dasari et al, 2022). Yeast models expressing human SNCA represent the most extensively studied system for PD. In yeast, α-synuclein recapitulates key features observed in human cells: it traffics via the secretory pathway to the plasma membrane, exhibit dose-dependent gain-of-function toxicity, and aggregates. Early studies demonstrated that the expression of one or two copies of SNCA under the control of a GAL promoter does not affect cell viability; α-synuclein folds correctly and localizes to the membrane. The expression of three copies is sufficient for α-synuclein aggregation affecting growth. With four copies the high toxicity of the resulted aggregates lead to cell death. These aggregates in yeast are clustered in vesicle structures reminiscent of the Lewy bodies (Outeiro and Lindquist, 2003). Yeast α-synuclein aggregation and vesicle accumulation lead to diverse cellular stressors. These include increase lipid droplet formation, proteasome inhibition, focal bursts of nitric oxide, ROS and protein nitration, mitochondrial dysfunction, and disrupted metal ion homeostasis; mitochondrial dysfunction is exacerbated in the presence of oxidants, such as menadione, which can be mitigated by melatonin addition and mitophagy activation (Zampol and Barros, 2018). Yeast studies reveal α-synuclein exists in dynamic equilibrium; altered protein levels content unbalance the equilibrium, recruiting functional membrane proteins into toxic cytoplasmic inclusions (Figure 1) (Outeiro and Lindquist, 2003). Crucially, a study demonstrated that even minimal expression of human α-synuclein induces the formation of respiration-deficient rho- petites mutants. Strikingly, α-synuclein is imported into mitochondria in yeast (Zhang et al., 2024), and full α-synuclein expression in petite cells triggers apoptosis, indicating that mitochondrial respiration is not absolutely required for α-synuclein-mediated cell death (Akintade and Chaudhuri, 2020). This finding provides new insights into Parkinson’s disease pathogenesis, suggesting that mitochondrial impairment, rather than complete function, may be crucial in α-synuclein toxicity. Notably, mutant forms of α-synuclein (A53T and A30P) did not induce petite formation, highlighting distinct mechanisms for wild-type toxicity. These findings support the hypothesis that early mitochondrial dysfunction contributes to neurodegeneration in PD. Finally, α-synuclein can also be found in the yeast nucleus, the nucleolar factor Dbp4, a DEAD-box helicase, stabilizes a fraction of α-synuclein oligomeric species, while its downregulation decreases α-synuclein toxicity and therefore the human ortholog DDX10 has emerged as a possible drug target (Popova et al., 2021).The relevance of α-synuclein segments in proper membrane localization was also investigated in yeast. Accordingly, the expression of an N-terminus truncated version of α-synuclein leads to the loss of membrane localization and it can be detected inside the mitochondria, likewise, expression of the truncated version of α-synuclein at the NAC domain reduced cytosolic accumulation (Soper et al., 2008; Zhang et al., 2024). Not only the wild type α-synuclein can lead to PD in humans, the point mutant alleles A53T and A30P are also associated with rare forms of early-onset familial PD and accelerate α-synuclein aggregation events (Narhi et al., 1999). Excess of the wild type, or A53T variant impaired the secretory pathway at early stages leading to vesicle accumulation and α-synuclein aggregation. Differently, the A30T variant showed reduced binding to membranes, failed to enter the secretory pathway and was less toxic for neurons and yeast cells (Dixon et al., 2005; Jensen et al., 1998; Outeiro and Lindquist, 2003). Using α-synuclein yeast expression system was possible to build a mutant library of 2600 possible α-synuclein single point mutants that exhaustively sample substitutions of each amino acid at every position, providing conditions to name substitutions that disrupt the toxic membrane-binding region (Newberry et al., 2020). Cellular stresses relevant to α-synuclein proteotoxicity has also been investigated in yeast cells, such as perturbations to vesicle trafficking and the endosomal network, oxidative stress, the unfolded protein response, calcineurin stimulation, protein degradation and autophagy, chaperone activity, and membrane composition (Shadrina and Slominsky, 2021; Menezes et al., 2015; Popova, Galka, et al., 2021). Cells overexpressing calcineurin B displayed an enhanced localization of A53T variant to the cytosolic membrane and lower aggregation, while proteasome inhibition by α-synuclein depends on yeast Rpn1 and the human counterpart PAAF1 (Chawla et al., 2023; Galka et al., 2024). Environmental inducers of synucleinopathies were also investigated using yeast, with the study of pesticides cymoxanil and metalaxyl promoting aggregation of α-synuclein (Amaral et al., 2024).Yeast genome-wide studies systematically screen the entire genome to identify every gene that modifies proteotoxicity when over-expressed or deleted. Using only the deletion collection, 86 gene mutants were shown to be more sensitive to α-synuclein (Willingham et al., 2003), however, combined tests of the mutant deletion collection with a pool of overexpression strains show a total of 332 genetic modifiers of α-synuclein toxicity. Another, overexpression study identified 54 suppressors and 23 enhancers of α-synuclein toxicity (Yeger-Lotem et al., 2009) In these studies, most genes clustered in processes related to a calcium signalling hub also linked to perturbed mitochondrial quality control and function (Khurana et al, 2017). With the toxicity of α-synuclein well established in yeast and compatible with the proteotoxicity present in neurons, experiments were designed to find compounds and drug candidates to halt the damage from α-synuclein-mediated toxicity. High-throughput screening of commercial chemical libraries in α-synuclein-expressing yeast identified bioactive compounds counteracting its toxicity. Initial screens highlighted the efficacy of 8-hydroxyquinoline metal chelators (Tardiff et al., 2012). Subsequent work identified N-aryl benzimidazole (NAB) as a more potent suppressor (Tardiff et al., 2013). The mechanism of action of NAB was indeed related to α-synuclein toxicity; with the identification of genetic changes that restore NAB target function, it was possible to verify that NAB promoted endosomal transport events disrupted by α-synuclein aggregates, i.e. those dependent on the E3 ubiquitin ligase Rsp5p/Nedd4 (Tardiff et al., 2013). After the identification of this druggable pathway in yeast, it was verified that NAB also protects cortical neurons derived from a patient with Parkinson’s disease, indicating that NAB engagement with Rsp5p/Nedd4 at its N-terminus improve endosomal transport and restore vesicle trafficking affected by α-synuclein cytotoxicity (Hatstat et al., 2021). The α-synuclein toxicity in yeast also lead to the identification of peptides and different drugs (AGK2, XCT790, phloretin, Cpd9) that counteract its aggregation and are candidates for the development of future therapeutic interventions (Ali et al., 2025; Popova et al., 2021; Suresh and Manjithaya, 2019; Du et al, 2019) . The flavonoid baicalein, known for neuroprotective effects including α-synuclein aggregation inhibition and oligomer disaggregation in mammalian models (Wang et al., 2013; Hu et al., 2016), significantly reduced α-synuclein toxicity in the sensitive yeast strain TK01. Remarkably, baicalein prevented cytotoxicity at concentrations lower than those effective in vitro, demonstrating the model’s enhanced sensitivity for detection (Zhu et al., 2004; Sangkaew et al., 2022). This validated baicalein’s neuroprotective potential and underscored the utility of yeast for discovering therapeutic candidates against neurodegeneration. 2- Alzheimer’s disease Alzheimer’s disease (AD) is the most common chronic neurodegenerative disease. AD is a progressive and irreversible disorder that causes memory loss. The progressive cognitive and behavioral symptoms that characterize AD elicits from functional changes observed in brain cells. While its origin is multifactorial, it is defined at the neuropathological molecular level by amyloid plaques and neurofibrillary tangles. Amyloid-β (Aβ) aggregation possibly leads to a cascade of pathogenic processes, such as inflammation, neurofibrillary tau-tangle formation, synapse dysfunction, neuronal death and cognitive impairment. The amyloid precursor protein (APP) is an integral membrane protein expressed in many tissues and concentrated in neurons; its role has been implicated as a regulator of synapse formation (Priller et al., 2006). Aβ peptides principally of 40 or 42 aa long are proteolysis products of APP by β- and γ-secretases. APP is processed by β-secretase in the extracellular space to produce a membrane-tethered fragment known as C99, which undergoes sequential cleavages by γ-secretase, generating a series of β-amyloid peptides. β- and γ-secretase activity are located in the endosomal compartment and trans-Golgi network; therefore Aβ is generated in these subcellular localizations and subsequently secreted through exocytosis. The Aβ 42-aa peptide is considered more toxic and more prone to produce oligomeric species than the Aβ 40-aa peptide (Jarrett et al., 1993). Aβ exists as monomers, dimers, higher oligomers, amyloid polymers, and amyloid fibrils.Genetic determinants for early-onset have been described in four genes: APP, PSEN1 (presenilin 1), PSEN2 (presenilin2), and SORL1 (Sortilin-Related Receptor 1) . Presenilin 1 and 2 are components of the γ-secretase complex, SORL1 encodes a neuronal sorting receptor involved in trafficking APP away from amyloidogenic pathways; mutations in these have high or complete penetrances to develop early-onset AD (Escamilla-Ayala et al., 2020; Jensen et al., 2023). For late-onset AD, the greatest genetic risk factor is the apolipoprotein ApoE. APOE encodes for three isoforms of a secreted 299 amino acid protein: apoE2, apoE3, and apoE4. One APOE-ε4 allele raises the risk to develop AD in three times, and the homozygous APOE-ε4/ APOE-ε4 condition has an eightfold risk (DiBattista et al., 2016). In the cellular neuropathology of AD, and other dementia processes, it is notable the formation neurofibrillary tangles resultant of hyperphosphorylated tau protein aggregates; its appearances can be caused by Aβ oligomerization and tau mutations (Oddo et al., 2003); tau proteins are a group of six highly soluble protein isoforms produced by MAPT gene alternative splicing; it is highly abundant in neurons with a direct role in axon microtubules stabilization. tau is phosphorylated by kinases such as GSK3α, GSK3β, MAPK13, and AMP-activated protein kinase; aberrant hyperphosphorylation occurs on several epitopes (Thr181, Thr231, Ser202, Ser205, Ser214, Ser396, Ser404, Ser409, and Ser422) (Trinczek et al., 1995).Studies with yeast models of tau toxicity have elucidated key aspects of tau phosphorylation and aggregation using conformation-dependent antibodies to detect pathological filament formation (De Vos et al., 2011; Vandebroek et al., 2005). Nevertheless, human tau protein was not found to aggregate in yeast (Zubčić et al., 2024). Yeast expresses functional orthologs of major human tau kinases: Mds1 corresponds to GSK3β, and Pho85 corresponds to CDK5. Intriguingly, pho85 mutants exhibited tau hyperphosphorylation at the AD2 and PG5 epitopes, mirroring the hyperphosphorylation observed upon CDK5 depletion in human systems with an inhibition of inositol phosphate and sphingolipids pathways (Randez-Gil et al., 2020); glucose starvation also lead to increased phosphorylation of tau protein in fission yeast (Yılmazer et al., 2025). Further investigation in yeast demonstrated distinct roles for these conserved kinases, showing that Mds1/GSK-3β acts genetically downstream of Pho85/CDK5. This work also revealed that oxidative stress triggers tau aggregation via a mechanism parallel to hyperphosphorylation (Vanhelmont et al., 2010). Additionally, the function of the prolyl isomerase Pin1 (yeast Ess1) was examined in yeast. Ess1 isomerizes phosphorylated tau, preventing or reversing filament formation, while its depletion resulted in tau hyperphosphorylation and impaired growth (De Vos et al., 2011). The synergic effect of tau and α-synuclein co-expression in yeast was investigated, with an increment of tau insolubility, correlated with increased tau phosphorylation in S396/404 (Ciaccioli et al., 2013).Yeast models have also been developed to investigate Aβ citoxicity (Dhakal and Macreadie, 2020). Early yeast studies were focused on the expression of the human APP protein and the identification of enzymes with secretase activity (Hines et al., 1994; Zhang et al., 1994). The γ-secretase was reconstituted in yeast by the co-expression of human PS, Nct, APH-1, and PEN-2 genes and its biological activity assessed (Yonemura et al., 2011). Using APP like reporters, this yeast heterologous system has been used to evaluate the pathogenicity of PS mutations found in AD patients (Imai et al., 2019). With the direct expression of Aβ peptides in yeast cytosol, it was possible to investigate the consequences of Aβ accumulation, such as the heat shock protein response (Caine et al., 2007), and the initial stages of Aβ oligomerization (Bagriantsev and Liebman, 2006). Aβ toxic oligomers indicate a protein-folding problem associated with other neurodegenerative diseases and with yeast prions (Shorter and Lindquist, 2004; Winderickx et al., 2008). The proper address of Aβ to yeast reticulum and the secretory pathway mimicked the multiple compartments distribution of Aβ through the secretory pathway (Treusch et al., 2011). Addressing of Aβ to the reticulum rendered lower growth rate, lower biomass yield, a lower respiratory rate, and increased oxidative stress (Chen and Petranovic, 2015; Treusch et al., 2011). Indeed, intracellular amyloid β (iAβ) is a strong player in neurodegeneration (Gallego Villarejo et al., 2022).The identification of phenotypes caused by Aβ toxicity in yeast allowed genetic screens for modifiers such as suppressors, or enhancers. Notably, a suppressor screen revealed that overexpression of VPS9 and other endocytic genes rescue Aβ toxicity. This demonstrated that endocytosis, particularly clathrin-mediated endocytosis (CME), is a critical point of vulnerability to Aβ. CME facilitates the internalization and recycling of receptors involved in diverse cellular processes (Treusch et al., 2011). Strikingly, several yeast genes identified as modifiers of Aβ toxicity encode homologs or functional partners of established human Alzheimer’s disease (AD) risk factors. These include PICALM (phosphatidylinositol binding clathrin assembly protein), BIN1, and CD2AP – all essential for CME in both yeast and humans. This conserved requirement strongly suggests that Aβ accumulation impairs the CME pathway. Overexpression of the yeast ortholog of PICALM reduced oligomerization of Aβ; likewise, a drug screen identified 7 compounds that reduce the oligomerization of the cytosolic form in yeast: bromperidol, haloperidol, azaperone, pramoxine HCl and dyclonine HCl, tamoxifen citrate, and minocycline HCl (Park et al., 2016). Using yeast Aβ reticulum-addressed model a genetic unbiased screen of 140,000 small compounds identified 8-hydroxyquinolines that partially rescue yeast cells from Aβ toxicity (Matlack et al., 2014); 8-hydroxyquinolines was similarly identified in earlier yeast screens using Aβ, TDP-43, and α-synuclein (Tardiff et al., 2012). Clioquinol is an 8-hydroxyquinolines that showed effective rescue of the yeast endocytosis pathway by promoting metal-dependent Aβ oligomers degradation within the secretory and endosomal compartments (Matlack et al., 2014). Synergic studies were also conducted in yeast, Trans-chalcone plus baicalein reduce intracellular Amyloid Beta (Aβ 42) (Dhakal et al., 2021). Interestingly, a synthetic genetic array (SGA) of yeast collection mutant with the yeast Aβ model identified among the affected genes FMN1, which encodes for riboflavin kinase necessary for flavin mononucleotide (FMN) production. In this study, the supplementation with FMN showed protection against Aβ oligomerization and improved redox homeostasis of the yeast cells (Chen et al., 2020).3- Huntington’s diseaseHuntington’s disease (HD) is a progressive neurological disorder whose triad of symptoms are motor dysfunction, cognitive impairment, and neuropsychiatric features. Involuntary movement disorder (chorea), voluntary movement impairment and bradykinesia are observed in the motor dysfunction component of the disease (Reilmann et al., 2014); problems of attention, mental flexibility, planning, emotion recognition and difficulty in speech may lead to social disengagement and decreased participation in conversations, and are collectively some of the cognitive impairment symptoms and, finally, irritability, depression, and apathy are observed as behavioral features (Papoutsi et al., 2014). Besides these symptoms, mood changes in the patients are fairly dramatic and that makes the situation more challenging to the families affected. HD is caused by a CAG expansion in the exon 1 of the Huntingtin gene (HTT) on chromosome 4, inherited in an autosomal dominant pattern. The CAG triplet encodes the amino acid glutamine, and its expansion forms a polyQ tract at the N-terminus of HTT, involved in the formation of oligomers and aggregates that are cytotoxic (DiFiglia et al., 1997). In typical individuals, the length of the CAG repeats is 16-20 on average, whereas in affected patients this expands to over 36 units. The number of CAG repeats in the mutant HTT allele is correlated inversely with the age in which the first diagnosable symptoms manifest; for adult-onset 40-50 repeats, while more than 60 is observed in juvenile HD (Lee et al., 2022; Langbehn et al., 2004).HTT aberrant splicing results in the production of a transcript containing only exon 1, expressing 17 amino acids of the N-terminal part followed by the polyglutamine (polyQ) tract, and a proline-rich domain, which is prone to aggregation inside the cell in disease (Bates et al., 2015). Similarly, proteases such as caspases and calpains cleave full-length HTT and generate an N-terminal fragment with a comparable organization (Graham et al., 2006; Gafni et al., 2001). As the concentration of this fragment builds up, it forms highly ordered β-sheet amyloid fibrils aggregates that may sequester protein quality control factors in the cytoplasm or transcription factors inside the nucleus, and disrupt cell´s activities (Jayaraman et al., 1998). Below we describe works that used HTT N-terminal fragment and some variants to model HD protein aggregation in yeast; to understand amyloid fibrils contribution to the loss of function observed in the cell, to track proteins and organelles affected and genes that either augment or diminish these phenotypes.The standard approach for the yeast model of HD is expressing the HTT exon 1 fused with GFP that allows protein aggregates observation by fluorescence microscopy. Besides, polyacrylamide gel electrophoresis (SDS-PAGE) followed by western blot is usually performed to verify soluble and insoluble polyQ proteins distribution. In this model, the expression of different N-terminal fragments of HTT containing 25, 47, 72, or 103 glutamine residues shows a polyQ length dependence on protein aggregation abundance (Dehay and Bertolotti, 2006; Krobitsch and Lindquist, 2000). The Q25 tract stays soluble and does not show any aggregation, but cells expressing Q103 contain most of the fusion protein insoluble in large aggregates (Krobitsch and Lindquist, 2000; Meriin et al., 2002). Interestingly, the deletion of the chaperone HSP104 abrogates the formation of aggregates completely, but its overexpression increases the number of fluorescent foci, indicating a protein folding control on the formation and dissolution of aggregates (Krobitsch and Lindquist, 2000). Moreover, the proline-rich region of HTT exon 1 is an important determinant for aggregation, indeed, this segment deletion strongly decreases Q103 aggregates formation (Dehay and Bertolotti, 2006). When expressed in yeast, Q103 alters mitochondrial function; it reduces oxygen consumption and diminishes complexes II and III activities of the mitochondrial respiratory chain (Solans et al., 2006), which also leads to elevates levels of ROS. A direct association between the polyQ tract and the mitochondrial outer membrane dissipates the mitochondrial membrane potential, decreases the energetic coupling, and impairs mitochondrial protein synthesis (Ocampo et al., 2010). This toxicity is partially by overexpression of HAP4, a central regulator of the transcription of many nuclear genes encoding mitochondrial proteins (Fontanesi et al., 2008); Hap4p rescues partially most of the aforementioned phenotypes although polyQ aggregates foci are at the same level of the control cells (Ocampo et al., 2010). Similarly, in multicellular organisms, PGC-1α is a transcriptional activator that regulates mitochondrial biogenesis and its excess in Drosophila melanogaster also attenuates polyQ-induced toxicity, indicating a conserved mechanism, and a possible intervention for HD treatment by modulation of PGC-1α levels (Ruetenik et al., 2016; Zhang et al., 2019; D’Egidio et al.,2025). Integrated multi-omic analysis of Huntington disease and yeast model show deregulated pathways that are common to human, mice and yeast systems including metabolism of various amino acids, glutathione metabolism, autophagy, mitophagy, and cell proteostasis (Pradhan et al., 2022; Takaine et al., 2022).PolyQ aggregates were studied in yeast in situ by cryoelectron tomography at a nanoscale resolution, the 3D images allowed the observation of unstructured inclusion bodies and less frequent fibrillar aggregates, in contrast to mammalian cells, where polyQ aggregates are exclusively fibrillar (Gruber et al., 2018). Cryoelectron tomography further reveals significant alterations in mitochondrial morphology. These changes occur without direct physical interaction with inclusions or fibrils and may arise from polyQ proteins inserted into the mitochondrial outer membrane (Ocampo et al., 2010). Fluorescence resonance energy transfer based method (FRET) can also be used to monitor polyQ aggregation in yeast individual cells (Wan et al., 2022).As previously mentioned in the Parkinson disease section, Hsp31p is the S. cerevisiae ortholog of human DJ-1 (PARK7), and a member of DJ-1/ThiJ/PfpI superfamily (Aslam & Hazbun, 2016) that translocates from the cytosol to the mitochondria upon redox challenge, and protects against reactive oxygen species (Bankapalli et al., 2015). Similarly, in the context of α-synuclein cytotoxicity, Hsp31p overexpression increases soluble Q72 levels. This prevents aggregation of the huntingtin N-terminal fragment and suppresses polyQ toxicity (Sajjad et al., 2014). Besides its effect on ROS production, whether Hsp31 affects polyQ association or effect on the outer mitochondrial membrane is yet to be explored.Screens for natural compounds or small molecules using the yeast model system offer a feasible approach to discover potential drug candidates for HD treatment. For instance, the component of green tea (-)-epigallocatechin-3-gallate (EGCG) inhibits polyQ aggregation in both yeast and fly models of HD (Ehrnhoefer et al., 2006; Varga et al., 2018). EGCG probably suppresses small polyQ oligomers formation and results in the formation of large ones, which may help the cell to sequester the mutant protein to prevent the disruption of its organelle’s function. A library containing ~11,000 natural products extracts from bacterial and fungal sources, isolated from Papua New Guinea, Costa Rica and other location, yielded four extracts that improve, by at least 30%, the growth of cells expressing Pro-Q103 (huntingtin toxic mutant that lacks the proline-rich domain) (Walter et al., 2014). Bioactivity-guided isolation of the active molecule found dactinomycin (actinomycin D), a transcription inhibitor, as the active part (Goldberg & Rabinowitz, 1962; Walter et al., 2014). In addition to suppressing cell growth, dactinomycin inhibits Q103 aggregation within a low concentration range (0.0005–0.5 µg/mL). This effect probably occurs through activation of the stress response and elevation of Hsp26p levels. The low effective dose holds therapeutic promise, as dactinomycin causes considerable side effects in oncology applications (Langholz et al., 2011). Finally, bioactive dietary compounds have been reported to modulate the solubility of huntingtin aggregates; notably, curcumin has been shown to interfere with the aggregation kinetics of HttEx1 in mammalian cells (Jain et al., 2025). Curcumin (a polyphenol present in the spice turmeric) decreases high molecular weight aggregates and increases lower molecular weight ones as observed in sucrose centrifugation gradients, and by fluorescence microscopy of Q72-GFP (Verma et al., 2012). Curcumin prevents polyglutamine aggregates formation by reducing Vps36p expression. This protein is a component of the ESCRT-II, the endosomal sorting complex required for transport, and the endocytic pathway and vacuolar protein sorting are known to affect mutant huntingtin aggregation (Meriin et al., 2002). Altogether, these works show how robust is the yeast model to find lead compounds that result in possible new treatment strategies for HD.Amyotrophic Lateral SclerosisAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease whose clinical manifestations in muscle include cramps, weakness, spasticity, and atrophy; it also causes respiratory insufficiency, difficulty in swallowing, difficulty with speech, cognitive and behavioral impairments (Brown and Al-Chalabi, 2017). Since cognitive and behavioral symptoms are observed in 50% of the patients (13% develop frontotemporal dementia) the initially motor neuron disease was redefined as a neurodegenerative disorder (Phukan et al., 2012). More than 30 genes are major risk factors of ALS, and cases of patients may show either a complex Mendelian inheritance pattern or no discernible family history. Four genes account for about 70% of all familial cases, to wit, C9orf72 (guanine nucleotide exchange C9orf72) (Brown and Al-Chalabi, 2017), FUS (RNA-binding protein, fused in sarcoma) ( Lagier-Tourenne et al., 2010), SOD1 (superoxide dismutase 1) (Siddique et al., 1991), and TARDBP (TAR DNA-binding protein 43) (Kabashi et al., 2008). As there are no published results on C9orf72 in S. cerevisiae, the following paragraphs present yeast ALS models used to understand the biology of FUS, SOD1, and TARDBP, related to the disease. While the primary cause of ALS remains unknown, a hallmark pathological feature involves the aggregation of FUS, SOD1, and TDP-43 into cytoplasmic inclusions within motor neurons – a key mechanism implicated in disease pathogenesis. In mutant forms, the RNA-binding protein FUS mislocalizes from the nucleus to the cytoplasm. This mislocalization impairs its function, disrupting critical RNA processing mechanisms. (Zhou et al., 2014). The FUS protein features an N-terminal prion-like domain, a glycine-rich domain, and a C-terminal region comprising one RNA recognition motif (RRM) followed by two Arg-Gly-Gly (RGG) repeats (Iko et al., 2004). FUS-GFP truncation constructs expressed in the yeast ALS model impair cell’s growth, and show that FUS determinants of aggregation are the first RGG repeat (amino acids 371–422) and the prion-like domain (amino acids 1–239). However, FUS inclusions in yeast are mostly cytosolic whereas in mammalian cells nearly all the protein is diffuse and nuclear (Fushimi et al., 2011; Kryndushkin et al., 2011; Sun et al., 2011). Expression of many ALS-linked FUS mutants, clustered at the C-terminal region, identified in some familial and sporadic cases of the disease (Lagier-Tourenne et al., 2010), shows a slight but not statistically significant reduction of FUS aggregates (Sun et al., 2011).FUS contains phosphorylation sites at the prion-like domain, which are a target of the DNA-dependent protein kinase (DNA-PK) (Deng et al., 2014). Upon treatment of the FUS ALS yeast model with calicheamicin, double-strand DNA breaks are formed and activate DNA-PK, which results in a dramatic mobility shift of FUS protein on SDS-PAGE gels, indicating its heavily phosphorylated status (Monahan et al., 2017). FUS phosphorylation sites analyzed from in vivo samples are found at S/TQ sites (target of DNA-PK) pT7, pS26, pS30, pS42, and pS61, but also non-S/TQ sites (pT71, pS77, and pS96). FUS phosphomimetics at these sites, or protein phosphorylation in vitro, prevent the formation of aggregates and show a more diffused protein in vivo both in yeast and human cell lines. Altogether, these results indicate that by controlling FUS phosphorylation states, protein aggregation can be reduced in cells.Over 234 genetic variants of the cytosolic human Cu, Zn superoxide dismutase 1 (hSOD1) are associated with the risk of ALS (Benatar et al., 2025). The use of these alleles in the hSOD1 ALS yeast model shows that copper binding capacity and superoxide scavenging activity are properties equally maintained by all mutants that depend on the SOD1 copper chaperone Ccs1p for effective copper loading. Metal binding and an intramolecular disulfide bond stabilize the hSOD1 homodimer structure in the wild type (WT) and ALS mutants, while loss of the intramolecular disulfide and formation of aberrant intermolecular disulfides aggregates the protein (Arnesano et al., 2004; Furukawa et al., 2006). Blocking copper activation in both Ccs1p and Ccs1p-independent pathways alters severely the protein stability of ALS mutants A4V, G93A, and G37R but not WT (Carroll et al., 2006). The oxidation/dimerization of apo-A4V hSOD1 in grx1 grx2 mutants reveals GRX’s critical role in suppressing aggregation of metal-depleted ALS hSOD1 mutants. This relevance is further evidenced by age-dependent accumulation of oxidized, high-mass SOD1-GFP inclusions in yeast cytoplasm (Brasil et al., 2019); evidence that oxidative damage is involved in the protein misfolding mechanisms observed in ALS and a clear connection to aging.In mouse motor neurons overexpressing WT hSOD1, a fraction of this protein is secreted in exosomes. Similarly, yeast Sod1p can be extracted from cell wall upon starvation in potassium acetate medium (Cruz-Garcia et al., 2017). Under this condition, the sorting of yeast Sod1p to the extracellular compartment requires an essential diacidic motif E77 and E78. By introducing the mutation G93A in yeast SOD1, an ALS-equivalent mutant is created whose cell wall extraction efficiency is similar to that of the WT protein. The mutant secretion is strongly impaired in triple mutant SOD1-DE77/78AA/G93A that also lacks the acidic motif. These findings in the yeast ALS model are very provocative, since secretion of ALS mutants may contribute to the propagation of SOD1 toxicity along neuroanatomical pathways, and also activate microglia to induce noncell-autonomous neurotoxicity (Grad et al., 2014).The same approach was used to generate yeast SOD1 mutants that are equivalent to ALS A4V, G37R, H48Q, G93A, and S134N alleles. In the sod1 null mutant, not all alleles were expressed at the same levels during logarithmic growth, probably due to their inherent instability; in WT SOD1 background all isoforms were overexpressed and therefore become stabilized (Bastow et al., 2016). This is probably an effect of heterodimerization, which also increases the number of intracellular inclusions and raises lipoperoxidation and protein carbonylation levels (Brasil et al., 2019). Heterodimers of wild-type and ALS-mutant SOD1 stabilize growth compared to sod1 mutant cells, where ALS mutants impair budding and are toxic (Bastow et al., 2016). This restored growth enables cells expressing sod1A3V or sod1G92A to upregulate trehalose—a protective adaptation to aggregates, confirmed by metabolomic and enzymatic assays. Notably, trehalose exerts neuroprotection in Sod1G93A-expressing mouse cells, likely by clearing aggregates via autophagy stimulation. In yeast, trehalose levels do not stimulate autophagy but deletion of trehalose-6-phosphate phosphatase Tps2p regulates this pathway (Kim et al., 2020).In many patients with ALS, the nuclear TAR DNA-binding protein 43 (TDP-43) is (Neumann et al., 2006). Mutations or high levels of TDP-43 cause ALS and in many patients the protein is cleaved, hyperphosphorylated, and translocated to the cytosol, where it is ubiquitinated (Mitchell et al., 2015). TDP-43 is an RNA-binding protein whose mislocation affects the processing of its target RNAs (Amlie-Wolf et al., 2015), but also endosomal trafficking, particularly dendritic endosomes, which results in reduced neuronal signaling. Expression of TDP-43 is toxic to S. cerevisiae, TDP-43 recapitulates nuclear localization when the protein is expressed integrated as a single copy in the yeast genome, but that changes drastically to multiple cytoplasmic aggregates when expressed from a high-copy (2 µ) plasmid (Johnson et al., 2008). The nature of this aggregation is surprisingly different because TDP-43 foci are not diminished in hsp101 mutant cells background like huntingtin N-terminal fragment, and, compared to the yeast prion [RNQ + ] that forms SDS-resistant high-molecular-weight amyloid-like structures. Intriguingly, TDP-43 has no amyloid-forming ability, and it is not stained by thioflavin T or Congo red, two known amyloid-binding dyes (Forman et al., 2007). The domain structure of TDP-43 is analogous to FUS; it has an N-terminal necessary for nuclear localization followed by two RRM motifs and a glycine-rich C-terminal prion-like domain. In this structure, the determinants of protein aggregation are the second RRM motif followed by the C-terminal prion-like domain (Johnson et al., 2008). A set of TDP-43 ALS-linked mutations cluster to the protein C-terminal. When expressing these mutants from a low copy (CEN) plasmid all of them are toxic and aggregate, some considerably more than the WT, and their expression causes cell death as indicated by propidium iodide staining (Johnson et al., 2009).Unbiased genetic screenings to find modifiers of TDP-43 toxicity in yeast found DBR1, which encodes an RNA lariat debranching enzyme, as a potent phenotype modifier, and knockdown of DBR1 gene validate this in human neuronal cell line and primary rat neurons (Armakola et al., 2012). Mutant DBR1 alleles lacking debranching function show that suppression of TDP-43 toxicity requires Dbr1p enzymatic activity, and expression of mouse Dbr1 in yeast dbr1 mutant cells restore this capacity, indicating that activity need is conserved from yeast to mammals. Since intronic lariats colocalize with TDP-43 foci in yeast, the picture that develops from these findings is that in the absence of Dbr1p enzymatic activity, intronic lariats accumulate in the cytoplasm and sequester TDP-43, preventing it from interfering with cellular functions. EGCG, first identified in yeast counteracting HTT oligomers, binds tandem RNA recognition motifs of TDP-43 and inhibits its aggregation (Morando et al., 2025). Another mammalian gene expressed in yeast causes TDP-43 aggregation, and it is related to the observed phosphorylation of the protein. A hyperactive C-terminal domain of the casein kinase 1δ (CK1δ1-317) induces TDP-43-GFP cytotoxicity in yeast and aggregation also in human neuroblastoma cells (Nonaka et al., 2016). This protein phosphorylates TDP-43 at Ser-409/410 residues, as revealed by immunoblotting. Furthermore, a recent genome-wide yeast screen identified additional modifiers of TDP-43 toxicity, including deletions of PBP1 and TIP41, which significantly alleviated TDP-43-induced cytotoxicity. These genes are involved in autophagy regulation, and their absence appears to enhance autophagic activity, suggesting that boosting autophagy may mitigate TDP-43 proteotoxicity (Park et al., 2019). Taken together, the findings mentioned in this paragraph points out some possible interventions to reduce TDP-43 toxicity in cells, by either reducing Dbr1 or CK1 activity.Expression of hSOD1 ALS mutant A4V in sod1 null mutant background shows an impact on the electron transport rates of complex III (70% reduction) and IV (55% reduction) when compared to the human WT protein (Gunther et al., 2004). Likewise, the mutant G93A reduced complex IV activity; but that of complex III was similar to the rate measured with mitochondria isolated from cells expressing WT hSOD1. In agreement with these data, heme content in A4V mutant cells shows an analogous decrease in hemes b, c-c 1 , and a-a 3 whereas G93A mutant shows a corresponding decrease in heme a-a 3 content. Yeast Sod1p partitions at 0.7% from the cytosol to the mitochondrial intermembrane space (IMS). By fusing its gene with the cytochrome b 2 bipartite mitochondrial targeting signal, b2-Sod1p migrates exclusively to the IMS, where it improves cells’ resistance to oxidants such as H 2 O 2 and paraquat, strongly reducing protein carbonylation (Klöppel et al., 2010). ALS-equivalent mutant sod1 G93A partitions at 4% of the total Sod1p to the IMS, performing similarly to the b2-Sod1p on the resistance to oxidants and protein carbonylation; however, the catalytically inactive sod1 G85R shows the same localization distribution of the WT Sod1p but performs as poorly as control sod1 null mutant cells. Surprisingly, the toxic effect of ALS-equivalent mutants is not on mitochondrial function, but an impairment on the acidification of the vacuole (Bastow et al., 2016); the yeast organelle functionally analogous of the human lysosome, leading to autophagy reduction. Nevertheless, previous work shows that the loss of vacuole acidity leads to mitochondrial dysfunction and that is linked to aging (Hughes & Gottschling, 2012), therefore, it is necessary more investigation to clarify these conflicting results. A final illustration of the usefulness of the hSOD1 ALS yeast model concerns a yeast interaction trap system used to identify proteins interacting with ALS sod1 G93A ( Kawamata et al., 2008). Lysyl-tRNA-synthetase (KARS) was found, and its interaction with the mutant validated. KARS enzyme exists as two isoforms one cytosolic (cytoKARS) and other mitochondrial (mitoKARS). In mammalian cells expressing normal hSOD1 or the mutants G93A or G85R, there is preferential interaction between mitoKARS and ALS mutants (Kawamata et al., 2008), and that also occurs in the brain and spinal cord of transgenic mice. As a consequence of this interaction, KARS misfolds and aggregates, and a fraction of the protein is degraded by the ubiquitin-proteasome system in the cytoplasm where the other accumulates in the organelle. Eventually, this alters mitochondrial morphology, impairs mitochondrial DNA-encoded protein synthesis, and leads to a decrease in survival.In mammalian cells, TDP-43 is localized to the mitochondria and promotes mitophagy (Hong et al., 2012). In the mouse model, this localization is increased by TDP-43 ALS mutations, and it is associated with mitochondrial dysfunction (Wang et al., 2013; Wang et al., 2016). When expressed in yeast TDP-43 does not affect the growth of cells on glucose medium (fermentation) but inhibits the growth on galactose (a condition where respiration and fermentation are present), and more severely the growth on ethanol or glycerol media, that promotes exclusively respiration (Park et al., 2019). Although TDP-43 aggregates in all media tested, it causes more aggregation on galactose and glycerol, when it is also observed an elongation phenotype of the cells (Park et al., 2019). This shows that TDP-43 is more toxic in respiring cells, and may pave the way to find the TDP-43 ALS mutants or structural determinants that, respectively, exacerbate or are linked to the phenotype. In summary, hSOD1 and TDP-43 ALS models found important aspects of these proteins related to the mitochondrial function that indicates cellular conditions that promote neurodegeneration in ALS and that can be studied further to find targets for small-molecule screens. Alternatively, although absent in metazoans, the disassembler protein Hsp104 effectively removes α-synuclein, TDP-43, and FUS aggregates in yeast. Engineered versions with increased aggregate specificity were developed to create therapeutics for neurodegenerative diseases. (Mack et al, 2023)

Altogether, the studies reported here demonstrate great advances achieved using yeast as a model organism to address fundamental problems directly related to neurodegenerative disease development. The study of import amyloidogenic disease-causing proteins in yeast leads to important discoveries about the metabolism and toxicity of such proteins in a simpler cell model, allowing the identification of partners and new factors involved in each pathway; more definitely the identification of chemicals and druggable pathways that can be the target of natural compounds or small molecules, that can be a potential treatment for each disease. Since yeast cells can be humanized way beyond the expression of only single aggregation-prone proteins, complex cellular dynamics may be studied when more human factors are added, to understand the biological problem in conditions that recapitulate the pathological events in neurons. Acknowledgments This work was supported by grants and fellowships from: Fundacao de Amparo a Pesquisa de Sao Paulo (FAPESP 2024/01152-3; 2023/14056-0) Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq 305054/2022-8). Coordenacao de Aperfeicoamento de Pessoal de Nıvel Superior – Brasil (CAPES). Author contributions – JRFJ, VLC and MHB conceived and drafted the manuscript as well as prepared the digital images. REFERENCES Akintade, D. D., & Chaudhuri, B. (2020). Apoptosis, Induced by Human α-Synuclein in Yeast, Can Occur Independent of Functional Mitochondria. Cells, 9 (10). https://doi.org/10.3390/cells9102203Ali, T. T., Merghani, M., Al-Azzani, M., Gatzemeier, L. M., Hoppert, M., Kaloyanova, D., Outeiro, T. F., Neumann, P., Popova, B., & Braus, G. H. (2025). Rationally designed peptides inhibit the formation of α-synuclein fibrils and oligomers. European Journal of Medicinal Chemistry, 289, 117452. https://doi.org/10.1016/j.ejmech.2025.117452Amaral, L., Mendes, F., Côrte-Real, M., Rego, A., Outeiro, T. F., & Chaves, S. R. (2024). A versatile yeast model identifies the pesticides cymoxanil and metalaxyl as risk factors for synucleinopathies. Chemosphere, 364, 143039. https://doi.org/10.1016/j.chemosphere.2024.143039Amlie-Wolf, A., Ryvkin, P., Tong, R., Dragomir, I., Suh, E., Xu, Y., Van Deerlin, V. M., Gregory, B. D., Kwong, L. K., Trojanowski, J. Q., Lee, V. M.-Y., Wang, L.-S., & Lee, E. B. (2015). Transcriptomic Changes Due to Cytoplasmic TDP-43 Expression Reveal Dysregulation of Histone Transcripts and Nuclear Chromatin. PloS One, 10 (10), e0141836. https://doi.org/10.1371/journal.pone.0141836Armakola, M., Higgins, M. J., Figley, M. D., Barmada, S. J., Scarborough, E. A., Diaz, Z., Fang, X., Shorter, J., Krogan, N. J., Finkbeiner, S., Farese, R. V. J., & Gitler, A. D. (2012). Inhibition of RNA lariat debranching enzyme suppresses TDP-43 toxicity in ALS disease models. Nature Genetics, 44 (12), 1302–1309. https://doi.org/10.1038/ng.2434Arnesano, F., Banci, L., Bertini, I., Martinelli, M., Furukawa, Y., & O’Halloran, T. V. (2004). The unusually stable quaternary structure of human Cu,Zn-superoxide dismutase 1 is controlled by both metal occupancy and disulfide status. The Journal of Biological Chemistry, 279 (46), 47998–48003. https://doi.org/10.1074/jbc.M406021200Aslam, K., & Hazbun, T. R. (2016). Hsp31, a member of the DJ-1 superfamily, is a multitasking stress responder with chaperone activity. Prion, 10 (2), 103–111. https://doi.org/10.1080/19336896.2016.1141858Aufschnaiter, A., Kohler, V., Walter, C., Tosal-Castano, S., Habernig, L., Wolinski, H., Keller, W., Vögtle, F.-N., & Büttner, S. (2018). The Enzymatic Core of the Parkinson’s Disease-Associated Protein LRRK2 Impairs Mitochondrial Biogenesis in Aging Yeast. Frontiers in Molecular Neuroscience, 11, 205. https://doi.org/10.3389/fnmol.2018.00205Bagriantsev, S., & Liebman, S. (2006). Modulation of Abeta42 low-n oligomerization using a novel yeast reporter system. BMC Biology, 4, 32. https://doi.org/10.1186/1741-7007-4-32Bankapalli, K., Saladi, S., Awadia, S. S., Goswami, A. V., Samaddar, M., & D’Silva, P. (2015). Robust glyoxalase activity of Hsp31, a ThiJ/DJ-1/PfpI family member protein, is critical for oxidative stress resistance in Saccharomyces cerevisiae. The Journal of Biological Chemistry, 290 (44), 26491–26507. https://doi.org/10.1074/jbc.M115.673624Bastow, E. L., Peswani, A. R., Tarrant, D. S. J., Pentland, D. R., Chen, X., Morgan, A., Staniforth, G. L., Tullet, J. M., Rowe, M. L., Howard, M. J., Tuite, M. F., & Gourlay, C. W. (2016). New links between SOD1 and metabolic dysfunction from a yeast model of amyotrophic lateral sclerosis. Journal of Cell Science, 129 (21), 4118–4129. https://doi.org/10.1242/jcs.190298Bates, G. P., Dorsey, R., Gusella, J. F., Hayden, M. R., Kay, C., Leavitt, B. R., Nance, M., Ross, C. A., Scahill, R. I., Wetzel, R., Wild, E. J., & Tabrizi, S. J. (2015). Huntington disease. Nature Reviews. Disease Primers, 1, 15005. https://doi.org/10.1038/nrdp.2015.5Benatar, M., Robertson, J., & Andersen, P. M. (2025). Amyotrophic lateral sclerosis caused by SOD1 variants: From genetic discovery to disease prevention. The Lancet. Neurology, 24 (1), 77–86. https://doi.org/10.1016/S1474-4422(24)00479-4Brasil, A. de A., de Carvalho, M. D. C., Gerhardt, E., Queiroz, D. D., Pereira, M. D., Outeiro, T. F., & Eleutherio, E. C. A. (2019). Characterization of the activity, aggregation, and toxicity of heterodimers of WT and ALS-associated mutant Sod1. Proceedings of the National Academy of Sciences of the United States of America, 116 (51), 25991–26000. https://doi.org/10.1073/pnas.1902483116Brown, R. H., & Al-Chalabi, A. (2017). Amyotrophic Lateral Sclerosis. The New England Journal of Medicine, 377 (2), 162–172. https://doi.org/10.1056/NEJMra1603471Caine, J., Sankovich, S., Antony, H., Waddington, L., Macreadie, P., Varghese, J., & Macreadie, I. (2007). Alzheimer’s Abeta fused to green fluorescent protein induces growth stress and a heat shock response. FEMS Yeast Research, 7 (8), 1230–1236. https://doi.org/10.1111/j.1567-1364.2007.00285.xCarroll, M. C., Outten, C. E., Proescher, J. B., Rosenfeld, L., Watson, W. H., Whitson, L. J., Hart, P. J., Jensen, L. T., & Cizewski Culotta, V. (2006). The effects of glutaredoxin and copper activation pathways on the disulfide and stability of Cu,Zn superoxide dismutase. The Journal of Biological Chemistry, 281 (39), 28648–28656. https://doi.org/10.1074/jbc.M600138200Cauchard, L., Angers, B., Boogert, N. J., & Doligez, B. (2016). Effect of an anti-malaria drug on behavioural performance on a problem-solving task: An experiment in wild great tits. Behavioural Processes, S0376-6357(16)30321-7. https://doi.org/10.1016/j.beproc.2016.10.012Chawla, S., Ahmadpour, D., Schneider, K. L., Kumar, N., Fischbach, A., Molin, M., & Nystrom, T. (Diretores). (2023, agosto 24). Calcineurin stimulation by Cnb1p overproduction mitigates protein aggregation and α-synuclein toxicity in a yeast model of synucleinopathy. (V. 21, Número 1) [Gravação de vídeo]. https://doi.org/10.1186/s12964-023-01242-wChen, X., Ji, B., Hao, X., Li, X., Eisele, F., Nyström, T., & Petranovic, D. (2020). FMN reduces Amyloid-β toxicity in yeast by regulating redox status and cellular metabolism. Nature Communications, 11 (1), 867. https://doi.org/10.1038/s41467-020-14525-4Ciaccioli, G., Martins, A., Rodrigues, C., Vieira, H., & Calado, P. (2013). A powerful yeast model to investigate the synergistic interaction of α-synuclein and tau in neurodegeneration. PloS One, 8 (2), e55848. https://doi.org/10.1371/journal.pone.0055848Cruz-Garcia, D., Brouwers, N., Duran, J. M., Mora, G., Curwin, A. J., & Malhotra, V. (2017). A diacidic motif determines unconventional secretion of wild-type and ALS-linked mutant SOD1. The Journal of Cell Biology, 216 (9), 2691–2700. https://doi.org/10.1083/jcb.201704056Dasari, A. K. R., Dillard, L., Yi, S., Viverette, E., Hojjatian, A., Sengupta, U., Kayed, R., Taylor, K. A., Borgnia, M. J., & Lim, K. H. (2022). Untwisted α-Synuclein Filaments Formed in the Presence of Lipid Vesicles. Biochemistry, 61 (17), 1766–1773. https://doi.org/10.1021/acs.biochem.2c00283Davidson, W. S., Jonas, A., Clayton, D. F., & George, J. M. (1998). Stabilization of alpha-synuclein secondary structure upon binding to synthetic membranes. The Journal of Biological Chemistry, 273 (16), 9443–9449. https://doi.org/10.1074/jbc.273.16.9443De Vos, A., Anandhakumar, J., Van den Brande, J., Verduyckt, M., Franssens, V., Winderickx, J., & Swinnen, E. (2011). Yeast as a model system to study tau biology. International Journal of Alzheimer’s Disease, 2011, 428970. https://doi.org/10.4061/2011/428970D’Egidio, F., Qosja, E., Ammannito, F., Topi, S., d’Angelo, M., Cimini, A., & Castelli, V. (2025). Antioxidant and Anti-Inflammatory Defenses in Huntington’s Disease: Roles of NRF2 and PGC-1α, and Therapeutic Strategies. Life (Basel, Switzerland), 15 (4). https://doi.org/10.3390/life15040577Dehay, B., & Bertolotti, A. (2006). Critical role of the proline-rich region in Huntingtin for aggregation and cytotoxicity in yeast. The Journal of Biological Chemistry, 281 (47), 35608–35615. https://doi.org/10.1074/jbc.M605558200Deng, Q., Holler, C. J., Taylor, G., Hudson, K. F., Watkins, W., Gearing, M., Ito, D., Murray, M. E., Dickson, D. W., Seyfried, N. T., & Kukar, T. (2014). FUS is phosphorylated by DNA-PK and accumulates in the cytoplasm after DNA damage. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience, 34 (23), 7802–7813. https://doi.org/10.1523/JNEUROSCI.0172-14.2014Dhakal, S., & Macreadie, I. (2020). Protein Homeostasis Networks and the Use of Yeast to Guide Interventions in Alzheimer’s Disease. International Journal of Molecular Sciences, 21 (21). https://doi.org/10.3390/ijms21218014Dhakal, S., Ramsland, P. A., Adhikari, B., & Macreadie, I. (2021). Trans-Chalcone Plus Baicalein Synergistically Reduce Intracellular Amyloid Beta (Aβ(42)) and Protect from Aβ(42) Induced Oxidative Damage in Yeast Models of Alzheimer’s Disease. International Journal of Molecular Sciences, 22 (17). https://doi.org/10.3390/ijms22179456Dhungel, N., Eleuteri, S., Li, L.-B., Kramer, N. J., Chartron, J. W., Spencer, B., Kosberg, K., Fields, J. A., Stafa, K., Adame, A., Lashuel, H., Frydman, J., Shen, K., Masliah, E., & Gitler, A. D. (2023). Parkinson’s Disease Genes VPS35 and EIF4G1 Interact Genetically and Converge on α-Synuclein. Neuron, 111 (1), 138. https://doi.org/10.1016/j.neuron.2022.12.020Di Battista, A. M., Heinsinger, N. M., & Rebeck, G. W. (2016). Alzheimer’s Disease Genetic Risk Factor APOE-ε4 Also Affects Normal Brain Function. Current Alzheimer Research, 13 (11), 1200–1207. https://doi.org/10.2174/1567205013666160401115127DiFiglia, M., Sapp, E., Chase, K. O., Davies, S. W., Bates, G. P., Vonsattel, J. P., & Aronin, N. (1997). Aggregation of huntingtin in neuronal intranuclear inclusions and dystrophic neurites in brain. Science (New York, N.Y.), 277 (5334), 1990–1993. https://doi.org/10.1126/science.277.5334.1990Dixon, C., Mathias, N., Zweig, R. M., Davis, D. A., & Gross, D. S. (2005). Alpha-synuclein targets the plasma membrane via the secretory pathway and induces toxicity in yeast. Genetics, 170 (1), 47–59. https://doi.org/10.1534/genetics.104.035493Du, Z., Valtierra, S., Cardona, L. R., Dunne, S. F., Luan, C.-H., & Li, L. (2019). Identifying Anti-prion Chemical Compounds Using a Newly Established Yeast High-Throughput Screening System. Cell Chemical Biology, 26 (12), 1664-1680.e4. https://doi.org/10.1016/j.chembiol.2019.10.004Ehrnhoefer, D. E., Duennwald, M., Markovic, P., Wacker, J. L., Engemann, S., Roark, M., Legleiter, J., Marsh, J. L., Thompson, L. M., Lindquist, S., Muchowski, P. J., & Wanker, E. E. (2006). Green tea (-)-epigallocatechin-gallate modulates early events in huntingtin misfolding and reduces toxicity in Huntington’s disease models. Human Molecular Genetics, 15 (18), 2743–2751. https://doi.org/10.1093/hmg/ddl210Escamilla-Ayala, A., Wouters, R., Sannerud, R., & Annaert, W. (2020). Contribution of the Presenilins in the cell biology, structure and function of γ-secretase. Seminars in Cell & Developmental Biology, 105, 12–26. https://doi.org/10.1016/j.semcdb.2020.02.005Fontanesi, F., Jin, C., Tzagoloff, A., & Barrientos, A. (2008). Transcriptional activators HAP/NF-Y rescue a cytochrome c oxidase defect in yeast and human cells. Human Molecular Genetics, 17 (6), 775–788. https://doi.org/10.1093/hmg/ddm349Forman, M. S., Trojanowski, J. Q., & Lee, V. M.-Y. (2007). TDP-43: A novel neurodegenerative proteinopathy. Current Opinion in Neurobiology, 17 (5), 548–555. https://doi.org/10.1016/j.conb.2007.08.005Furukawa, Y., Fu, R., Deng, H.-X., Siddique, T., & O’Halloran, T. V. (2006). Disulfide cross-linked protein represents a significant fraction of ALS-associated Cu, Zn-superoxide dismutase aggregates in spinal cords of model mice. Proceedings of the National Academy of Sciences of the United States of America, 103 (18), 7148–7153. https://doi.org/10.1073/pnas.0602048103Fushimi, K., Long, C., Jayaram, N., Chen, X., Li, L., & Wu, J. Y. (2011). Expression of human FUS/TLS in yeast leads to protein aggregation and cytotoxicity, recapitulating key features of FUS proteinopathy. Protein & Cell, 2 (2), 141–149. https://doi.org/10.1007/s13238-011-1014-5Gafni, J., Hermel, E., Young, J. E., Wellington, C. L., Hayden, M. R., & Ellerby, L. M. (2004). Inhibition of calpain cleavage of huntingtin reduces toxicity: Accumulation of calpain/caspase fragments in the nucleus. The Journal of Biological Chemistry, 279 (19), 20211–20220. https://doi.org/10.1074/jbc.M401267200Galka, D., Ali, T. T., Bast, A., Niederleithinger, M., Gerhardt, E., Motosugi, R., Sakata, E., Knop, M., Outeiro, T. F., Popova, B., & Braus, G. H. (2024). Inhibition of 26S proteasome activity by α-synuclein is mediated by the proteasomal chaperone Rpn14/PAAF1. Aging Cell, 23 (5), e14128. https://doi.org/10.1111/acel.14128Gallego Villarejo, L., Bachmann, L., Marks, D., Brachthäuser, M., Geidies, A., & Müller, T. (2022). Role of Intracellular Amyloid β as Pathway Modulator, Biomarker, and Therapy Target. International Journal of Molecular Sciences, 23 (9). https://doi.org/10.3390/ijms23094656Giasson, B. I., Murray, I. V., Trojanowski, J. Q., & Lee, V. M. (2001). A hydrophobic stretch of 12 amino acid residues in the middle of alpha-synuclein is essential for filament assembly. The Journal of Biological Chemistry, 276 (4), 2380–2386. https://doi.org/10.1074/jbc.M008919200Gitler, A. D., Chesi, A., Geddie, M. L., Strathearn, K. E., Hamamichi, S., Hill, K. J., Caldwell, K. A., Caldwell, G. A., Cooper, A. A., Rochet, J.-C., & Lindquist, S. (2009). Alpha-synuclein is part of a diverse and highly conserved interaction network that includes PARK9 and manganese toxicity. Nature Genetics, 41 (3), 308–315. https://doi.org/10.1038/ng.300GOLDBERG, I. H., & RABINOWITZ, M. (1962). Actionmycin D inhibition of deoxyribonucleic acid-dependent synthesis of ribonucleic acid. Science (New York, N.Y.), 136 (3513), 315–316. https://doi.org/10.1126/science.136.3513.315Grad, L. I., Yerbury, J. J., Turner, B. J., Guest, W. C., Pokrishevsky, E., O’Neill, M. A., Yanai, A., Silverman, J. M., Zeineddine, R., Corcoran, L., Kumita, J. R., Luheshi, L. M., Yousefi, M., Coleman, B. M., Hill, A. F., Plotkin, S. S., Mackenzie, I. R., & Cashman, N. R. (2014). Intercellular propagated misfolding of wild-type Cu/Zn superoxide dismutase occurs via exosome-dependent and -independent mechanisms. Proceedings of the National Academy of Sciences of the United States of America, 111 (9), 3620–3625. https://doi.org/10.1073/pnas.1312245111Graham, R. K., Deng, Y., Slow, E. J., Haigh, B., Bissada, N., Lu, G., Pearson, J., Shehadeh, J., Bertram, L., Murphy, Z., Warby, S. C., Doty, C. N., Roy, S., Wellington, C. L., Leavitt, B. R., Raymond, L. A., Nicholson, D. W., & Hayden, M. R. (2006). Cleavage at the caspase-6 site is required for neuronal dysfunction and degeneration due to mutant huntingtin. Cell, 125 (6), 1179–1191. https://doi.org/10.1016/j.cell.2006.04.026Gruber, A., Hornburg, D., Antonin, M., Krahmer, N., Collado, J., Schaffer, M., Zubaite, G., Lüchtenborg, C., Sachsenheimer, T., Brügger, B., Mann, M., Baumeister, W., Hartl, F. U., Hipp, M. S., & Fernández-Busnadiego, R. (2018). Molecular and structural architecture of polyQ aggregates in yeast. Proceedings of the National Academy of Sciences of the United States of America, 115 (15), E3446–E3453. https://doi.org/10.1073/pnas.1717978115Gunther, M. R., Vangilder, R., Fang, J., & Beattie, D. S. (2004). Expression of a familial amyotrophic lateral sclerosis-associated mutant human superoxide dismutase in yeast leads to decreased mitochondrial electron transport. Archives of Biochemistry and Biophysics, 431 (2), 207–214. https://doi.org/10.1016/j.abb.2004.08.009Hatstat, A. K., Ahrendt, H. D., Foster, M. W., Mayne, L., Moseley, M. A., Englander, S. W., & McCafferty, D. G. (2021). Characterization of Small-Molecule-Induced Changes in Parkinson’s-Related Trafficking via the Nedd4 Ubiquitin Signaling Cascade. Cell Chemical Biology, 28 (1), 14-25.e9. https://doi.org/10.1016/j.chembiol.2020.10.008Hines, V., Zhang, W., Ramakrishna, N., Styles, J., Mehta, P., Kim, K. S., Innis, M., & Miller, D. L. (1994). The expression and processing of human beta-amyloid peptide precursors in Saccharomyces cerevisiae: Evidence for a novel endopeptidase in the yeast secretory system. Cellular & Molecular Biology Research, 40 (4), 273–284.Hong, K., Li, Y., Duan, W., Guo, Y., Jiang, H., Li, W., & Li, C. (2012). Full-length TDP-43 and its C-terminal fragments activate mitophagy in NSC34 cell line. Neuroscience Letters, 530 (2), 144–149. https://doi.org/10.1016/j.neulet.2012.10.003Hughes, A. L., & Gottschling, D. E. (2012). An early age increase in vacuolar pH limits mitochondrial function and lifespan in yeast. Nature, 492 (7428), 261–265. https://doi.org/10.1038/nature11654Iko, Y., Kodama, T. S., Kasai, N., Oyama, T., Morita, E. H., Muto, T., Okumura, M., Fujii, R., Takumi, T., Tate, S., & Morikawa, K. (2004). Domain architectures and characterization of an RNA-binding protein, TLS. The Journal of Biological Chemistry, 279 (43), 44834–44840. https://doi.org/10.1074/jbc.M408552200Imai, S., Cai, T., Yoshida, C., Tomita, T., & Futai, E. (2019). Specific mutations in presenilin 1 cause conformational changes in γ-secretase to modulate amyloid β trimming. Journal of Biochemistry, 165 (1), 37–46. https://doi.org/10.1093/jb/mvy081Ishikawa, T. (2021). Saccharomyces cerevisiae in neuroscience: How unicellular organism helps to better understand prion protein? Neural Regeneration Research, 16 (3), 489–495. https://doi.org/10.4103/1673-5374.293137Jain, G., Trombetta-Lima, M., Matlahov, I., Ribas, H. T., Chen, T., Parlato, R., Portale, G., Dolga, A. M., & van der Wel, P. C. A. (2025). Inhibitor-based modulation of huntingtin aggregation mechanisms mitigates fibril-induced cellular stress. Nature Communications, 16 (1), 3588. https://doi.org/10.1038/s41467-025-58691-9Jakes, R., Spillantini, M. G., & Goedert, M. (1994). Identification of two distinct synucleins from human brain. FEBS Letters, 345 (1), 27–32. https://doi.org/10.1016/0014-5793(94)00395-5Jana, M., Dasarathy, S., Ghosh, S., & Pahan, K. (2023). Upregulation of DJ-1 in Dopaminergic Neurons by a Physically-Modified Saline: Implications for Parkinson’s Disease. International Journal of Molecular Sciences, 24 (5). https://doi.org/10.3390/ijms24054652Jarrett, J. T., Berger, E. P., & Lansbury, P. T. J. (1993). The carboxy terminus of the beta amyloid protein is critical for the seeding of amyloid formation: Implications for the pathogenesis of Alzheimer’s disease. Biochemistry, 32 (18), 4693–4697. https://doi.org/10.1021/bi00069a001Jayaraman, M., Kodali, R., Sahoo, B., Thakur, A. K., Mayasundari, A., Mishra, R., Peterson, C. B., & Wetzel, R. (2012). Slow amyloid nucleation via α-helix-rich oligomeric intermediates in short polyglutamine-containing huntingtin fragments. Journal of Molecular Biology, 415 (5), 881–899. https://doi.org/10.1016/j.jmb.2011.12.010Jensen, A. M. G., Kitago, Y., Fazeli, E., Vægter, C. B., Small, S. A., Petsko, G. A., & Andersen, O. M. (2023). Dimerization of the Alzheimer’s disease pathogenic receptor SORLA regulates its association with retromer. Proceedings of the National Academy of Sciences of the United States of America, 120 (4), e2212180120. https://doi.org/10.1073/pnas.2212180120Jensen, P. H., Nielsen, M. S., Jakes, R., Dotti, C. G., & Goedert, M. (1998). Binding of alpha-synuclein to brain vesicles is abolished by familial Parkinson’s disease mutation. The Journal of Biological Chemistry, 273 (41), 26292–26294. https://doi.org/10.1074/jbc.273.41.26292Jiang, Y., & MacNeil, L. T. (2023). Simple model systems reveal conserved mechanisms of Alzheimer’s disease and related tauopathies. Molecular Neurodegeneration, 18 (1), 82. https://doi.org/10.1186/s13024-023-00664-xJimenez-Harrison, D., Huseby, C. J., Hoffman, C. N., Sher, S., Snyder, D., Seal, B., Yuan, C., Fu, H., Wysocki, V., Giorgini, F., & Kuret, J. (2023). DJ-1 Molecular Chaperone Activity Depresses Tau Aggregation Propensity through Interaction with Monomers. Biochemistry, 62 (5), 976–988. https://doi.org/10.1021/acs.biochem.2c00581Johnson, B. S., McCaffery, J. M., Lindquist, S., & Gitler, A. D. (2008). A yeast TDP-43 proteinopathy model: Exploring the molecular determinants of TDP-43 aggregation and cellular toxicity. Proceedings of the National Academy of Sciences of the United States of America, 105 (17), 6439–6444. https://doi.org/10.1073/pnas.0802082105Kabashi, E., Valdmanis, P. N., Dion, P., Spiegelman, D., McConkey, B. J., Vande Velde, C., Bouchard, J.-P., Lacomblez, L., Pochigaeva, K., Salachas, F., Pradat, P.-F., Camu, W., Meininger, V., Dupre, N., & Rouleau, G. A. (2008). TARDBP mutations in individuals with sporadic and familial amyotrophic lateral sclerosis. Nature Genetics, 40 (5), 572–574. https://doi.org/10.1038/ng.132Kawamata, H., Magrané, J., Kunst, C., King, M. P., & Manfredi, G. (2008). Lysyl-tRNA synthetase is a target for mutant SOD1 toxicity in mitochondria. The Journal of Biological Chemistry, 283 (42), 28321–28328. https://doi.org/10.1074/jbc.M805599200Khurana, V., Chung, C. Y., & Tardiff, D. F. (2017). From Yeast to Patients: The Audacity and Vision of Susan Lindquist. Cell Systems, 4 (2), 147–148. https://doi.org/10.1016/j.cels.2017.02.007Khurana, V., Peng, J., Chung, C. Y., Auluck, P. K., Fanning, S., Tardiff, D. F., Bartels, T., Koeva, M., Eichhorn, S. W., Benyamini, H., Lou, Y., Nutter-Upham, A., Baru, V., Freyzon, Y., Tuncbag, N., Costanzo, M., San Luis, B.-J., Schöndorf, D. C., Barrasa, M. I., … Lindquist, S. (2017). Genome-Scale Networks Link Neurodegenerative Disease Genes to α-Synuclein through Specific Molecular Pathways. Cell Systems, 4 (2), 157-170.e14. https://doi.org/10.1016/j.cels.2016.12.011Kim, B., Lee, Y., Choi, H., & Huh, W.-K. (2021). The trehalose-6-phosphate phosphatase Tps2 regulates ATG8 transcription and autophagy in Saccharomyces cerevisiae. Autophagy, 17 (4), 1013–1027. https://doi.org/10.1080/15548627.2020.1746592Klöppel, C., Michels, C., Zimmer, J., Herrmann, J. M., & Riemer, J. (2010). In yeast redistribution of Sod1 to the mitochondrial intermembrane space provides protection against respiration derived oxidative stress. Biochemical and Biophysical Research Communications, 403 (1), 114–119. https://doi.org/10.1016/j.bbrc.2010.10.129Krobitsch, S., & Lindquist, S. (2000). Aggregation of huntingtin in yeast varies with the length of the polyglutamine expansion and the expression of chaperone proteins. Proceedings of the National Academy of Sciences of the United States of America, 97 (4), 1589–1594. https://doi.org/10.1073/pnas.97.4.1589Kryndushkin, D., Wickner, R. B., & Shewmaker, F. (2011). FUS/TLS forms cytoplasmic aggregates, inhibits cell growth and interacts with TDP-43 in a yeast model of amyotrophic lateral sclerosis. Protein & Cell, 2 (3), 223–236. https://doi.org/10.1007/s13238-011-1525-0Lagier-Tourenne, C., Polymenidou, M., & Cleveland, D. W. (2010). TDP-43 and FUS/TLS: emerging roles in RNA processing and neurodegeneration. Human Molecular Genetics, 19 (R1), R46-64. https://doi.org/10.1093/hmg/ddq137Langbehn, D. R., Brinkman, R. R., Falush, D., Paulsen, J. S., & Hayden, M. R. (2004). A new model for prediction of the age of onset and penetrance for Huntington’s disease based on CAG length. Clinical Genetics, 65 (4), 267–277. https://doi.org/10.1111/j.1399-0004.2004.00241.xLangholz, B., Skolnik, J. M., Barrett, J. S., Renbarger, J., Seibel, N. L., Zajicek, A., & Arndt, C. A. S. (2011). Dactinomycin and vincristine toxicity in the treatment of childhood cancer: A retrospective study from the Children’s Oncology Group. Pediatric Blood & Cancer, 57 (2), 252–257. https://doi.org/10.1002/pbc.22882Lee, J.-M., Huang, Y., Orth, M., Gillis, T., Siciliano, J., Hong, E., Mysore, J. S., Lucente, D., Wheeler, V. C., Seong, I. S., McLean, Z. L., Mills, J. A., McAllister, B., Lobanov, S. V., Massey, T. H., Ciosi, M., Landwehrmeyer, G. B., Paulsen, J. S., Dorsey, E. R., … Gusella, J. F. (2022). Genetic modifiers of Huntington disease differentially influence motor and cognitive domains. American Journal of Human Genetics, 109 (5), 885–899. https://doi.org/10.1016/j.ajhg.2022.03.004Lindquist, S. (1997). Mad cows meet psi-chotic yeast: The expansion of the prion hypothesis. Cell, 89 (4), 495–498. https://doi.org/10.1016/s0092-8674(00)80231-7Lindquist, S., DebBurman, S. K., Glover, J. R., Kowal, A. S., Liu, J. J., Schirmer, E. C., & Serio, T. R. (1998). Amyloid fibres of Sup35 support a prion-like mechanism of inheritance in yeast. Biochemical Society Transactions, 26 (3), 486–490. https://doi.org/10.1042/bst0260486Mack, K. L., Kim, H., Barbieri, E. M., Lin, J., Braganza, S., Jackrel, M. E., DeNizio, J. E., Yan, X., Chuang, E., Tariq, A., Cupo, R. R., Castellano, L. M., Caldwell, K. A., Caldwell, G. A., & Shorter, J. (2023). Tuning Hsp104 specificity to selectively detoxify α-synuclein. Molecular Cell, 83 (18), 3314-3332.e9. https://doi.org/10.1016/j.molcel.2023.07.029Marte, L., Boronat, S., Barrios, R., Barcons-Simon, A., Bolognesi, B., Cabrera, M., Ayté, J., & Hidalgo, E. (2022). Expression of Huntingtin and TDP-43 Derivatives in Fission Yeast Can Cause Both Beneficial and Toxic Effects. International Journal of Molecular Sciences, 23 (7). https://doi.org/10.3390/ijms23073950Matlack, K. E. S., Tardiff, D. F., Narayan, P., Hamamichi, S., Caldwell, K. A., Caldwell, G. A., & Lindquist, S. (2014). Clioquinol promotes the degradation of metal-dependent amyloid-β (Aβ) oligomers to restore endocytosis and ameliorate Aβ toxicity. Proceedings of the National Academy of Sciences of the United States of America, 111 (11), 4013–4018. https://doi.org/10.1073/pnas.1402228111Menezes, R., Tenreiro, S., Macedo, D., Santos, C. N., & Outeiro, T. F. (2015). From the baker to the bedside: Yeast models of Parkinson’s disease. Microbial Cell (Graz, Austria), 2 (8), 262–279. https://doi.org/10.15698/mic2015.08.219Meriin, A. B., Zhang, X., He, X., Newnam, G. P., Chernoff, Y. O., & Sherman, M. Y. (2002). Huntington toxicity in yeast model depends on polyglutamine aggregation mediated by a prion-like protein Rnq1. The Journal of Cell Biology, 157 (6), 997–1004. https://doi.org/10.1083/jcb.200112104Miller-Fleming, L., Antas, P., Pais, T. F., Smalley, J. L., Giorgini, F., & Outeiro, T. F. (2014). Yeast DJ-1 superfamily members are required for diauxic-shift reprogramming and cell survival in stationary phase. Proceedings of the National Academy of Sciences of the United States of America, 111 (19), 7012–7017. https://doi.org/10.1073/pnas.1319221111Mitchell, J. C., Constable, R., So, E., Vance, C., Scotter, E., Glover, L., Hortobagyi, T., Arnold, E. S., Ling, S.-C., McAlonis, M., Da Cruz, S., Polymenidou, M., Tessarolo, L., Cleveland, D. W., & Shaw, C. E. (2015). Wild type human TDP-43 potentiates ALS-linked mutant TDP-43 driven progressive motor and cortical neuron degeneration with pathological features of ALS. Acta Neuropathologica Communications, 3, 36. https://doi.org/10.1186/s40478-015-0212-4Monahan, Z., Ryan, V. H., Janke, A. M., Burke, K. A., Rhoads, S. N., Zerze, G. H., O’Meally, R., Dignon, G. L., Conicella, A. E., Zheng, W., Best, R. B., Cole, R. N., Mittal, J., Shewmaker, F., & Fawzi, N. L. (2017). Phosphorylation of the FUS low-complexity domain disrupts phase separation, aggregation, and toxicity. The EMBO Journal, 36 (20), 2951–2967. https://doi.org/10.15252/embj.201696394Morando, M. A., D’Alessandro, V., Spinello, A., Sollazzo, M., Monaca, E., Sabbatella, R., Volpe, M. C., Gervaso, F., Polini, A., Mizielinska, S., & Alfano, C. (2025). Epigallocatechin-3-gallate binds tandem RNA recognition motifs of TDP-43 and inhibits its aggregation. Scientific Reports, 15 (1), 17879. https://doi.org/10.1038/s41598-025-02035-6Moskovitz, B., & Levin, D. R. (1988). Pretreatment regimen for high-risk patients receiving urographic contrast media. European Urology, 15 (1–2), 94–95. https://doi.org/10.1159/000473404Narhi, L., Wood, S. J., Steavenson, S., Jiang, Y., Wu, G. M., Anafi, D., Kaufman, S. A., Martin, F., Sitney, K., Denis, P., Louis, J. C., Wypych, J., Biere, A. L., & Citron, M. (1999). Both familial Parkinson’s disease mutations accelerate alpha-synuclein aggregation. The Journal of Biological Chemistry, 274 (14), 9843–9846. https://doi.org/10.1074/jbc.274.14.9843Neumann, M., Sampathu, D. M., Kwong, L. K., Truax, A. C., Micsenyi, M. C., Chou, T. T., Bruce, J., Schuck, T., Grossman, M., Clark, C. M., McCluskey, L. F., Miller, B. L., Masliah, E., Mackenzie, I. R., Feldman, H., Feiden, W., Kretzschmar, H. A., Trojanowski, J. Q., & Lee, V. M.-Y. (2006). Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science (New York, N.Y.), 314 (5796), 130–133. https://doi.org/10.1126/science.1134108Nonaka, T., Suzuki, G., Tanaka, Y., Kametani, F., Hirai, S., Okado, H., Miyashita, T., Saitoe, M., Akiyama, H., Masai, H., & Hasegawa, M. (2016). Phosphorylation of TAR DNA-binding Protein of 43 kDa (TDP-43) by Truncated Casein Kinase 1δ Triggers Mislocalization and Accumulation of TDP-43. The Journal of Biological Chemistry, 291 (11), 5473–5483. https://doi.org/10.1074/jbc.M115.695379Ocampo, A., Zambrano, A., & Barrientos, A. (2010). Suppression of polyglutamine-induced cytotoxicity in Saccharomyces cerevisiae by enhancement of mitochondrial biogenesis. FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology, 24 (5), 1431–1441. https://doi.org/10.1096/fj.09-148601Outeiro, T. F., & Lindquist, S. (2003). Yeast cells provide insight into alpha-synuclein biology and pathobiology. Science (New York, N.Y.), 302 (5651), 1772–1775. https://doi.org/10.1126/science.1090439Papoutsi, M., Labuschagne, I., Tabrizi, S. J., & Stout, J. C. (2014). The cognitive burden in Huntington’s disease: Pathology, phenotype, and mechanisms of compensation. Movement Disorders : Official Journal of the Movement Disorder Society, 29 (5), 673–683. https://doi.org/10.1002/mds.25864Park, S.-K., Park, S., & Liebman, S. W. (2019). Respiration Enhances TDP-43 Toxicity, but TDP-43 Retains Some Toxicity in the Absence of Respiration. Journal of Molecular Biology, 431 (10), 2050–2059. https://doi.org/10.1016/j.jmb.2019.03.014Park, S.-K., Ratia, K., Ba, M., Valencik, M., & Liebman, S. W. (2016). Inhibition of Aβ(42) oligomerization in yeast by a PICALM ortholog and certain FDA approved drugs. Microbial Cell (Graz, Austria), 3 (2), 53–64. https://doi.org/10.15698/mic2016.02.476Pereira, C., Costa, V., Martins, L. M., & Saraiva, L. (2015). A yeast model of the Parkinson’s disease-associated protein Parkin. Experimental Cell Research, 333 (1), 73–79. https://doi.org/10.1016/j.yexcr.2015.02.018Phukan, J., Elamin, M., Bede, P., Jordan, N., Gallagher, L., Byrne, S., Lynch, C., Pender, N., & Hardiman, O. (2012). The syndrome of cognitive impairment in amyotrophic lateral sclerosis: A population-based study. Journal of Neurology, Neurosurgery, and Psychiatry, 83 (1), 102–108. https://doi.org/10.1136/jnnp-2011-300188Popova, B., Galka, D., Häffner, N., Wang, D., Schmitt, K., Valerius, O., Knop, M., & Braus, G. H. (2021). α-Synuclein Decreases the Abundance of Proteasome Subunits and Alters Ubiquitin Conjugates in Yeast. Cells, 10 (9). https://doi.org/10.3390/cells10092229Popova, B., Wang, D., Pätz, C., Akkermann, D., Lázaro, D. F., Galka, D., Kolog Gulko, M., Bohnsack, M. T., Möbius, W., Bohnsack, K. E., Outeiro, T. F., & Braus, G. H. (2021). DEAD-box RNA helicase Dbp4/DDX10 is an enhancer of α-synuclein toxicity and oligomerization. PLoS Genetics, 17 (3), e1009407. https://doi.org/10.1371/journal.pgen.1009407Popova, B., Wang, D., Rajavel, A., Dhamotharan, K., Lázaro, D. F., Gerke, J., Uhrig, J. F., Hoppert, M., Outeiro, T. F., & Braus, G. H. (2021). Identification of Two Novel Peptides That Inhibit α-Synuclein Toxicity and Aggregation. Frontiers in Molecular Neuroscience, 14, 659926. https://doi.org/10.3389/fnmol.2021.659926Pradhan, S. S., Thota, S. M., Rajaratnam, S., Bhagavatham, S. K. S., Pulukool, S. K., Rathnakumar, S., Phalguna, K. S., Dandamudi, R. B., Pargaonkar, A., Joseph, P., Joshy, E. V., & Sivaramakrishnan, V. (2022). Integrated multi-omics analysis of Huntington disease identifies pathways that modulate protein aggregation. Disease Models & Mechanisms, 15 (10). https://doi.org/10.1242/dmm.049492Priller, C., Bauer, T., Mitteregger, G., Krebs, B., Kretzschmar, H. A., & Herms, J. (2006). Synapse formation and function is modulated by the amyloid precursor protein. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience, 26 (27), 7212–7221. https://doi.org/10.1523/JNEUROSCI.1450-06.2006Randez-Gil, F., Bojunga, L., Estruch, F., Winderickx, J., Del Poeta, M., & Prieto, J. A. (2020). Sphingolipids and Inositol Phosphates Regulate the Tau Protein Phosphorylation Status in Humanized Yeast. Frontiers in Cell and Developmental Biology, 8, 592159. https://doi.org/10.3389/fcell.2020.592159Reilmann, R., Leavitt, B. R., & Ross, C. A. (2014). Diagnostic criteria for Huntington’s disease based on natural history. Movement Disorders : Official Journal of the Movement Disorder Society, 29 (11), 1335–1341. https://doi.org/10.1002/mds.26011Ruetenik, A., & Barrientos, A. (2018). Exploiting Post-mitotic Yeast Cultures to Model Neurodegeneration. Frontiers in Molecular Neuroscience, 11, 400. https://doi.org/10.3389/fnmol.2018.00400Ruetenik, A. L., Ocampo, A., Ruan, K., Zhu, Y., Li, C., Zhai, R. G., & Barrientos, A. (2016). Attenuation of polyglutamine-induced toxicity by enhancement of mitochondrial OXPHOS in yeast and fly models of aging. Microbial Cell (Graz, Austria), 3 (8), 338–351. https://doi.org/10.15698/mic2016.08.518Sajjad, M. U., Green, E. W., Miller-Fleming, L., Hands, S., Herrera, F., Campesan, S., Khoshnan, A., Outeiro, T. F., Giorgini, F., & Wyttenbach, A. (2014). DJ-1 modulates aggregation and pathogenesis in models of Huntington’s disease. Human Molecular Genetics, 23 (3), 755–766. https://doi.org/10.1093/hmg/ddt466Sangkaew, A., Kojornna, T., Tanahashi, R., Takagi, H., & Yompakdee, C. (2022). A novel yeast-based screening system for potential compounds that can alleviate human α-synuclein toxicity. Journal of Applied Microbiology, 132 (2), 1409–1421. https://doi.org/10.1111/jam.15256Seirafi, M., Kozlov, G., & Gehring, K. (2015). Parkin structure and function. The FEBS Journal, 282 (11), 2076–2088. https://doi.org/10.1111/febs.13249Shadrina, M., & Slominsky, P. (2021). Modeling Parkinson’s Disease: Not Only Rodents? Frontiers in Aging Neuroscience, 13, 695718. https://doi.org/10.3389/fnagi.2021.695718Shorter, J., & Lindquist, S. (2004). Hsp104 catalyzes formation and elimination of self-replicating Sup35 prion conformers. Science (New York, N.Y.), 304 (5678), 1793–1797. https://doi.org/10.1126/science.1098007Siddique, T., Figlewicz, D. A., Pericak-Vance, M. A., Haines, J. L., Rouleau, G., Jeffers, A. J., Sapp, P., Hung, W. Y., Bebout, J., & McKenna-Yasek, D. (1991). Linkage of a gene causing familial amyotrophic lateral sclerosis to chromosome 21 and evidence of genetic-locus heterogeneity. The New England Journal of Medicine, 324 (20), 1381–1384. https://doi.org/10.1056/NEJM199105163242001Simonetti, B., & Cullen, P. J. (2018). Endosomal Sorting: Architecture of the Retromer Coat. Current Biology : CB, 28 (23), R1350–R1352. https://doi.org/10.1016/j.cub.2018.10.040Söderback, I., Bengtsson, I., Ginsburg, E., & Ekholm, J. (1992). Video feedback in occupational therapy: Its effects in patients with neglect syndrome. Archives of Physical Medicine and Rehabilitation, 73 (12), 1140–1146.Solans, A., Zambrano, A., Rodríguez, M., & Barrientos, A. (2006). Cytotoxicity of a mutant huntingtin fragment in yeast involves early alterations in mitochondrial OXPHOS complexes II and III. Human Molecular Genetics, 15 (20), 3063–3081. https://doi.org/10.1093/hmg/ddl248Soper, J. H., Roy, S., Stieber, A., Lee, E., Wilson, R. B., Trojanowski, J. Q., Burd, C. G., & Lee, V. M.-Y. (2008). Alpha-synuclein-induced aggregation of cytoplasmic vesicles in Saccharomyces cerevisiae. Molecular Biology of the Cell, 19 (3), 1093–1103. https://doi.org/10.1091/mbc.e07-08-0827Stella, R., Bertoli, A., Lopreiato, R., & Peggion, C. (2025). A Twist in Yeast: New Perspectives for Studying TDP-43 Proteinopathies in S. cerevisiae. Journal of Fungi (Basel, Switzerland), 11 (3). https://doi.org/10.3390/jof11030188Sun, Z., Diaz, Z., Fang, X., Hart, M. P., Chesi, A., Shorter, J., & Gitler, A. D. (2011). Molecular determinants and genetic modifiers of aggregation and toxicity for the ALS disease protein FUS/TLS. PLoS Biology, 9 (4), e1000614. https://doi.org/10.1371/journal.pbio.1000614Suresh, S. N., & Manjithaya, R. (2019). A small molecule autophagy inducer exerts cytoprotection against α-synuclein toxicity. European Journal of Pharmacology, 862, 172635. https://doi.org/10.1016/j.ejphar.2019.172635Surguchov, A. (2021). Invertebrate Models Untangle the Mechanism of Neurodegeneration in Parkinson’s Disease. Cells, 10 (2). https://doi.org/10.3390/cells10020407Takaine, M., Imamura, H., & Yoshida, S. (2022). High and stable ATP levels prevent aberrant intracellular protein aggregation in yeast. eLife, 11 . https://doi.org/10.7554/eLife.67659Tardiff, D. F., Jui, N. T., Khurana, V., Tambe, M. A., Thompson, M. L., Chung, C. Y., Kamadurai, H. B., Kim, H. T., Lancaster, A. K., Caldwell, K. A., Caldwell, G. A., Rochet, J.-C., Buchwald, S. L., & Lindquist, S. (2013). Yeast reveal a “druggable” Rsp5/Nedd4 network that ameliorates α-synuclein toxicity in neurons. Science (New York, N.Y.), 342 (6161), 979–983. https://doi.org/10.1126/science.1245321Tardiff, D. F., Tucci, M. L., Caldwell, K. A., Caldwell, G. A., & Lindquist, S. (2012). Different 8-hydroxyquinolines protect models of TDP-43 protein, α-synuclein, and polyglutamine proteotoxicity through distinct mechanisms. The Journal of Biological Chemistry, 287 (6), 4107–4120. https://doi.org/10.1074/jbc.M111.308668Treusch, S., Hamamichi, S., Goodman, J. L., Matlack, K. E. S., Chung, C. Y., Baru, V., Shulman, J. M., Parrado, A., Bevis, B. J., Valastyan, J. S., Han, H., Lindhagen-Persson, M., Reiman, E. M., Evans, D. A., Bennett, D. A., Olofsson, A., DeJager, P. L., Tanzi, R. E., Caldwell, K. A., … Lindquist, S. (2011). Functional links between Aβ toxicity, endocytic trafficking, and Alzheimer’s disease risk factors in yeast. Science (New York, N.Y.), 334 (6060), 1241–1245. https://doi.org/10.1126/science.1213210Trinczek, B., Biernat, J., Baumann, K., Mandelkow, E. M., & Mandelkow, E. (1995). Domains of tau protein, differential phosphorylation, and dynamic instability of microtubules. Molecular Biology of the Cell, 6 (12), 1887–1902. https://doi.org/10.1091/mbc.6.12.1887Vandebroek, T., Vanhelmont, T., Terwel, D., Borghgraef, P., Lemaire, K., Snauwaert, J., Wera, S., Van Leuven, F., & Winderickx, J. (2005). Identification and isolation of a hyperphosphorylated, conformationally changed intermediate of human protein tau expressed in yeast. Biochemistry, 44 (34), 11466–11475. https://doi.org/10.1021/bi0506775Vanhelmont, T., Vandebroek, T., De Vos, A., Terwel, D., Lemaire, K., Anandhakumar, J., Franssens, V., Swinnen, E., Van Leuven, F., & Winderickx, J. (2010). Serine-409 phosphorylation and oxidative damage define aggregation of human protein tau in yeast. FEMS Yeast Research, 10 (8), 992–1005. https://doi.org/10.1111/j.1567-1364.2010.00662.xVarga, J., Dér, N. P., Zsindely, N., & Bodai, L. (2020). Green tea infusion alleviates neurodegeneration induced by mutant Huntingtin in Drosophila. Nutritional Neuroscience, 23 (3), 183–189. https://doi.org/10.1080/1028415X.2018.1484021Verma, M., Sharma, A., Naidu, S., Bhadra, A. K., Kukreti, R., & Taneja, V. (2012). Curcumin prevents formation of polyglutamine aggregates by inhibiting Vps36, a component of the ESCRT-II complex. PloS One, 7 (8), e42923. https://doi.org/10.1371/journal.pone.0042923Walter, G. M., Raveh, A., Mok, S.-A., McQuade, T. J., Arevang, C. J., Schultz, P. J., Smith, M. C., Asare, S., Cruz, P. G., Wisen, S., Matainaho, T., Sherman, D. H., & Gestwicki, J. E. (2014). High-throughput screen of natural product extracts in a yeast model of polyglutamine proteotoxicity. Chemical Biology & Drug Design, 83 (4), 440–449. https://doi.org/10.1111/cbdd.12259Wan, Q., Mouton, S. N., Veenhoff, L. M., & Boersma, A. J. (2022). A FRET-based method for monitoring structural transitions in protein self-organization. Cell Reports Methods, 2 (3), 100184. https://doi.org/10.1016/j.crmeth.2022.100184Wang, W., Li, L., Lin, W.-L., Dickson, D. W., Petrucelli, L., Zhang, T., & Wang, X. (2013). The ALS disease-associated mutant TDP-43 impairs mitochondrial dynamics and function in motor neurons. Human Molecular Genetics, 22 (23), 4706–4719. https://doi.org/10.1093/hmg/ddt319Wang, W., Wang, L., Lu, J., Siedlak, S. L., Fujioka, H., Liang, J., Jiang, S., Ma, X., Jiang, Z., da Rocha, E. L., Sheng, M., Choi, H., Lerou, P. H., Li, H., & Wang, X. (Diretores). (2016, agosto). The inhibition of TDP-43 mitochondrial localization blocks its neuronal toxicity. (V. 22, Número 8) [Gravação de vídeo]. https://doi.org/10.1038/nm.4130Wang, Y.-H., Yu, H.-T., Pu, X.-P., & Du, G.-H. (2013). Baicalein prevents 6-hydroxydopamine-induced mitochondrial dysfunction in SH-SY5Y cells via inhibition of mitochondrial oxidation and up-regulation of DJ-1 protein expression. Molecules (Basel, Switzerland), 18 (12), 14726–14738. https://doi.org/10.3390/molecules181214726Willingham, S., Outeiro, T. F., DeVit, M. J., Lindquist, S. L., & Muchowski, P. J. (2003). Yeast genes that enhance the toxicity of a mutant huntingtin fragment or alpha-synuclein. Science (New York, N.Y.), 302 (5651), 1769–1772. https://doi.org/10.1126/science.1090389Winderickx, J., Delay, C., De Vos, A., Klinger, H., Pellens, K., Vanhelmont, T., Van Leuven, F., & Zabrocki, P. (2008). Protein folding diseases and neurodegeneration: Lessons learned from yeast. Biochimica et Biophysica Acta, 1783 (7), 1381–1395. https://doi.org/10.1016/j.bbamcr.2008.01.020Xiong, Y., Coombes, C. E., Kilaru, A., Li, X., Gitler, A. D., Bowers, W. J., Dawson, V. L., Dawson, T. M., & Moore, D. J. (2010). GTPase activity plays a key role in the pathobiology of LRRK2. PLoS Genetics, 6 (4), e1000902. https://doi.org/10.1371/journal.pgen.1000902Yeger-Lotem, E., Riva, L., Su, L. J., Gitler, A. D., Cashikar, A. G., King, O. D., Auluck, P. K., Geddie, M. L., Valastyan, J. S., Karger, D. R., Lindquist, S., & Fraenkel, E. (2009). Bridging high-throughput genetic and transcriptional data reveals cellular responses to alpha-synuclein toxicity. Nature Genetics, 41 (3), 316–323. https://doi.org/10.1038/ng.337Yılmazer, M., Şengelen, A., Aksüt, Y., Palabıyık, B., Önay-Uçar, E., & Karaer Uzuner, S. (2025). Glucose starvation induces tau phosphorylation leading to cellular stress response in fission yeast. Archives of Microbiology, 207 (7), 148. https://doi.org/10.1007/s00203-025-04350-yYonemura, Y., Futai, E., Yagishita, S., Suo, S., Tomita, T., Iwatsubo, T., & Ishiura, S. (2011). Comparison of presenilin 1 and presenilin 2 γ-secretase activities using a yeast reconstitution system. The Journal of Biological Chemistry, 286 (52), 44569–44575. https://doi.org/10.1074/jbc.M111.270108Zampol, M. A., & Barros, M. H. (2018). Melatonin improves survival and respiratory activity of yeast cells challenged by alpha-synuclein and menadione. Yeast (Chichester, England), 35 (3), 281–290. https://doi.org/10.1002/yea.3296Zhang, H., Komano, H., Fuller, R. S., Gandy, S. E., & Frail, D. E. (1994). Proteolytic processing and secretion of human beta-amyloid precursor protein in yeast. Evidence for a yeast secretase activity. The Journal of Biological Chemistry, 269 (45), 27799–27802.Zhang, Q., Lei, Y.-H., Zhou, J.-P., Hou, Y.-Y., Wan, Z., Wang, H.-L., & Meng, H. (2019). Role of PGC-1α in Mitochondrial Quality Control in Neurodegenerative Diseases. Neurochemical Research, 44 (9), 2031–2043. https://doi.org/10.1007/s11064-019-02858-6Zhang, X., Ruan, L., Wang, H., Zhu, J., Li, T., Sun, G., Dong, Y., Wang, Y., Berreby, G., Shay, A., Chen, R., Ramachandran, S., Dawson, V. L., Dawson, T. M., & Li, R. (2024). Enhancing mitochondrial proteolysis alleviates alpha-synuclein-mediated cellular toxicity. NPJ Parkinson’s Disease, 10 (1), 120. https://doi.org/10.1038/s41531-024-00733-yZhou, Y., Liu, S., Oztürk, A., & Hicks, G. G. (2014). FUS-regulated RNA metabolism and DNA damage repair: Implications for amyotrophic lateral sclerosis and frontotemporal dementia pathogenesis. Rare Diseases (Austin, Tex.), 2, e29515. https://doi.org/10.4161/rdis.29515Zhu, M., Rajamani, S., Kaylor, J., Han, S., Zhou, F., & Fink, A. L. (2004). The flavonoid baicalein inhibits fibrillation of alpha-synuclein and disaggregates existing fibrils. The Journal of Biological Chemistry, 279 (26), 26846–26857. https://doi.org/10.1074/jbc.M403129200Zondler, L., Miller-Fleming, L., Repici, M., Gonçalves, S., Tenreiro, S., Rosado-Ramos, R., Betzer, C., Straatman, K. R., Jensen, P. H., Giorgini, F., & Outeiro, T. F. (2014). DJ-1 interactions with α-synuclein attenuate aggregation and cellular toxicity in models of Parkinson’s disease. Cell Death & Disease, 5 (7), e1350. https://doi.org/10.1038/cddis.2014.307Zubčić, K., Franić, D., Pravica, M., Hof, P. R., Šimić, G., & Boban, M. (2024). Effects of heterologous human tau protein expression in yeast models of proteotoxic stress response. CNS Neuroscience & Therapeutics, 30 (6), e14304. https://doi.org/10.1111/cns.14304 Figure Legends Figure 1 - Yeast as a model of Parkinson’s disease and intracellular proteostasis. Yeast plasmids expressing, α-synuclein, and LRRK2 can be incorporated in the yeast genome. The fate of α-synuclein is depicted sequentially from translation in the endoplasmic reticulum (ER) towards the secretory pathway and the plasma membrane. Abnormal α-synuclein accumulation may occur in the cytosol and after ubiquitinylation it is initially degraded by the proteasome or it can misfold and form oligomeric species that fibrillate. The autophagosome is formed; it can fuse to lysosomes, promoting the recycling of the oligomeric and fibrillate species of α-synuclein in the vacuole. When the proteostasis is lost, large aggregates of α-synuclein are formed disrupting endocytosis, vesicular transport, vacuolar autophagy and mitochondrial activity as well as promoting lipid droplets formation. LRRK2 expression cause disruption of the secretory pathway and blocks mitochondrial function, while Parkin promotes mitophagy. Figure 2 – Yeast as a model of Alzheimer disease. The figure illustrates APP and tau. Protein aggregation is driven by the Aβ peptide (from APP) and tau’s microtubule-binding domain. Furthermore, Aβ oligomers enhance tau hyperphosphorylation by activating Mds1. The diagram also identifies endocytosis-promoting factors and therapeutic agents that alleviate oligomers cytotoxicity. Importantly, the cascading detrimental effects of Aβ and tau aggregates on protein quality control and mitochondrial function mirror the mechanisms previously shown for α-synuclein aggregates (Figure 1) Figure 3 – Yeast as model of Huntington disease: In yeast models of Huntington’s disease, expression of huntingtin fragments with pathogenic (Q103) versus non-pathogenic (Q25) polyglutamine lengths reveals distinct fates. While the Q25 fragment remains soluble, the Q103 fragment forms aggregates. These aggregates disrupt cellular proteostasis and impair mitochondrial function, specifically reducing the activity of respiratory complexes II and III. This mitochondrial dysfunction is further characterized by a decreased membrane potential and diminished mitochondrial protein synthesis. Notably, certain molecular factors, such as Hsp31 and drugs can mitigate the detrimental effects of these aggregates. Figure 4 – Yeast as model of ALS disease. The FUS and TDP-43 domains are depicted with the prion-like region that promotes aggregation indicated in brown. Factors involved in the promotion or inhibition of the oligomers formation are also indicated. Information & Authors Information Version history Peer review timeline Published Yeast Version of Record24 Nov 2025Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection

Authors Metrics & Citations Metrics Article Usage 439views 195downloads Citations Download citation Jose Ferreira-Junior, Vittoria de Lima Camandona, Mario Barros. From Yeast to Therapeutics: Modeling Neurodegenerative Diseases in S. cerevisiae. Authorea. 23 July 2025. DOI: https://doi.org/10.22541/au.175323435.52513536/v1 DOI: https://doi.org/10.22541/au.175323435.52513536/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.