Involved in the regulation of oxidative phosphorylation and energy metabolism (PubMed:23857330, PubMed:23812712). Necessary for the assembly of mitochondrial respiratory supercomplex (PubMed:23857330, PubMed:23812712). Interacts with the mitochondrial respiratory supercomplex. By estrogen and silica. Knockout homozygous mice manifest decreased mitochondrial respiratory activities and impaired formation of mitochondrial supercomplexes in muscles. KO animals have muscle weakness and exhibit heat production failure in the cold. Belongs to the cytochrome c oxidase VIIa family.