Structure of zebrafish NLRP3 reveals a novel mode of inflammasome activation

Structure of zebrafish NLRP3 reveals a novel mode of inflammasome activation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Structure of zebrafish NLRP3 reveals a novel mode of inflammasome activation Lisa Dopslaff, María Mateo-Tórtola, Varvara Varlamova, Corinna Gehring-Khav, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9449872/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract NLRP3 is an innate immune sensor of a broad range of stimuli, which upon activation forms a multiprotein inflammasome complex triggering caspase-1 activation, IL-1β and IL-18 maturation, and inflammatory cell death. The canonical NLRP3 activation pathway has been well characterized from a structural perspective. It involves the association of NLRP3 with membranes in the form of inactive oligomeric “cage” complexes, which, upon activation, convert to an active oligomeric NLRP3 disc. NLRP3 structural rearrangements during non-classical NLRP3 activation pathways, however, remain unknown. Here, we report a novel mode of NLRP3 activation utilized by the NLRP3 homolog from zebrafish. The cryo-EM structure of zebrafish NLRP3 shows that, unlike human NLRP3, it forms disc-shaped heptamers that undergo further trimerization, resulting in a 21-mer oligomeric arrangement. Surprisingly, a single zebrafish NLRP3 heptamer cannot arrange its PYD domains into a PYD helix and therefore requires a trimer of heptamers to form a PYD filament that enables ASC oligomerization. Furthermore, zebrafish NLRP3 does not associate with the Golgi network, nor does it form inactive “cage” oligomers or interact with NEK7. Thus, our data demonstrate an ancestral non-canonical structural mechanism of NLRP3 activation, which may shed light on alternative NLRP3 activation pathways present in humans. Biological sciences/Structural biology/Electron microscopy/Cryoelectron microscopy Biological sciences/Immunology/Innate immunity/Pattern recognition receptors/NOD-like receptors Biological sciences/Immunology/Inflammation/Inflammasome NLRP3 inflammasome zebrafish inflammation innate immunity cryo-EM Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9449872","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":627933157,"identity":"1fc7a030-52bd-4a9a-84a3-cb38a7596979","order_by":0,"name":"Lisa Dopslaff","email":"","orcid":"","institution":"University Hospital Tübingen","correspondingAuthor":false,"prefix":"","firstName":"Lisa","middleName":"","lastName":"Dopslaff","suffix":""},{"id":627933158,"identity":"b3afb017-8204-4553-84e4-1326e5421da2","order_by":1,"name":"María Mateo-Tórtola","email":"","orcid":"https://orcid.org/0000-0002-3412-2028","institution":"University of 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