Mitochondrial protein that plays a regulatory role in cellular metabolism, particularly under hypoxic conditions (PubMed:22100406). Downregulates mitochondrial respiratory chain complex I activity under hypoxia, reduces oxygen consumption and ROS and helps cells adapt by switching to glycolysis (PubMed:22100406). . This is the function of ENSG00000185633 (COXFA4L2, cytochrome c oxidase hypoxia associated subunit FA4L2).