ATAD3A has a scaffolding role regulating mitochondria inner membrane structure and protein assembly

The ATPase Family AAA Domain Containing 3A (ATAD3A) is a mitochondrial inner membrane protein conserved in metazoans. ATAD3A has been associated with several mitochondrial functions, including nucleoid organization, cholesterol metabolism, and mitochondrial translation. To address its primary role, we generated a neuronal-specific conditional knockout (Atad3 nKO) mouse model, which developed a severe encephalopathy by 5 months of age. Pre-symptomatic mice showed aberrant mitochondrial cristae morphogenesis in the cortex as early as 2 months. Using a multi-omics approach in the CNS of 2-3-month-old mice, we found early alterations in the organelle membrane structure. We also showed that human ATAD3A associates with different components of the inner membrane, including: OXPHOS complex I, Letm1 and prohibitin complexes. Stochastic Optical Reconstruction Microscopy (STORM) showed that ATAD3A is regularly distributed along the inner mitochondrial membrane, suggesting a critical structural role in inner mitochondrial membrane and its organization, most likely in an ATPase-dependent manner. Total RNA from cortex tissues of 2.5-month-old Atad3 nKO male mice and control littermates (5 biological replicates per group).