COA1 (cytochrome c oxidase assembly factor 1) is a mitochondrial protein that plays a crucial role in respiratory chain complex assembly and regulation. As a component of the MITRAC (mitochondrial translation regulation assembly intermediate of cytochrome c oxidase complex) complex, COA1 regulates cytochrome c oxidase assembly by coordinating both the translation of mitochondrial-encoded components and the assembly of nuclear-encoded components imported into mitochondria 1. The protein is required for assembly of mitochondrial respiratory chain complex I and complex IV, functioning as part of the MCIA complex for efficient complex I assembly 1. COA1 is located on the inner mitochondrial membrane where it facilitates protein assembly processes essential for oxidative phosphorylation. In disease contexts, COA1 has shown oncogenic properties, being overexpressed across various cancer types and correlating with poor prognosis 1. The gene serves as a target for tumor suppressor microRNAs miR-127-3p and miR-376a-3p in giant cell tumor of bone, where COA1 silencing reduces tumor growth 2. Evolutionary studies reveal that COA1 can be conditionally dispensable in species with glycolytic-dependent muscle fibers, showing recurrent gene loss events in certain mammalian lineages 3. These findings highlight COA1's dual role in normal mitochondrial function and pathological processes.