Cytochrome C Oxidase Assembly Protein 15 (COX15)

COX15 is predicted to contain 5 transmembrane domains localized in the mitochondrial inner membrane. Alternative splicing of this gene generates two transcript variants diverging in the 3' region.

The amino acid sequences of both isoforms are 42% identical to that of yeast cox15. Sequence analysis indicated that COX15 contains a mitochondrial leader peptide and 5 transmembrane domains. Using in vitro mitochondrial import and trypsin-protection assays, the authors demonstrated that the COX15 protein is targeted to mitochondria. Northern blot analysis revealed that COX15 is expressed as 1.5-, 1.8-, and 3-kb mRNAs predominantly in tissues characterized by high rates of oxidative phosphorylation (OXPHOS), including muscle, heart, and brain.