Cytochrome C Oxidase Assembly Factor COX14 (also known as PCAG1, MC4DN10 and C12orf62) is located on human chromosome 12q13.12. The COX14 gene encodes a small single-pass transmembrane protein that localizes to mitochondria. This protein may play a role in coordinating the early steps of cytochrome c oxidase (COX; also known as complex IV) subunit assembly and, in particular, the synthesis and assembly of the COX I subunit of the holoenzyme. Mutations in COX14 gene have been associated with mitochondrial complex IV deficiency. Alternative splicing results in multiple transcript variants.