COX14 is a core component of the MITRAC complex that regulates cytochrome c oxidase (complex IV) assembly by coordinating early assembly steps with mitochondrial COX1 synthesis 1. COX14 functions as a translational regulator of COX1, the central mitochondrial-encoded subunit of complex IV 1. Mechanistically, COX14 forms an early assembly intermediate with newly synthesized COX1 and cooperates with assembly factors COA3 and CMC1 to stabilize COX1 prior to incorporation of nuclear-encoded subunits 23. This stabilization occurs independently of metallation factors, suggesting COX14's primary role is COX1 turnover regulation rather than cofactor insertion 2. Mutations in COX14 cause mitochondrial complex IV deficiency (nuclear type 10), a severe mitochondrial disorder 3. In COX14-deficient mice, impaired COX1 translation leads to complex IV dysfunction, triggering increased reactive oxygen species production and secondary mitochondrial RNA release into the cytosol, causing RIG-I-mediated liver inflammation and tissue-specific pathologies 4. The interdependence between COX14 and COA3 demonstrates their coordinated roles in early complex IV biogenesis 3. Notably, disease severity varies by tissue, with some patients showing milder phenotypes including neuropathy, exercise intolerance, obesity, and short stature 3.