Depletion of Toxoplasma adenine nucleotide translocator leads to defects in mitochondrial morphology

Background: The adenine nucleotide translocase (ANT) is a protein that catalyzes the exchange of ADP/ATP across the inner mitochondrial membrane. Beyond this, ANT is closely associated with cell death pathways and mitochondrial dysfunction. It is a potential therapeutic target for many diseases. The function of the ANT in T. gondii is poorly understood. Methods: The CRISPR/CAS9 system was used to identify and study the function of the ANT protein in T. gondii . The location of TgANT was determined by proteinase K (PK) protection and mitochondrial permeabilization assays. Mitochondrial morphology was observed by immunofluorescence and transmission electron microscopy (TEM). Results: Our results showed that T. gondii encoded an ANT protein, which was designated TgANT. TgANT localized to the inner mitochondrial membrane (IMM). The proliferation of the Δant strain was significantly reduced. More important, depletion of TgANT resulted in significant morphological and ultrastructure changes in the mitochondria and abnormal cytoskeletal daughter budding. Furthermore, the pathogenicity of Δant strain to mice was significantly reduced. Conclusions: Altogether, we identified and characterized the ANT protein of T. gondii . Depletion of TgANT inhibited parasites growth and resulted in mitochondrial morphological defects and abnormal cytoskeletal daughter budding, suggesting TgANT is important for parasite growth.