Identification of TMEM126A as OXA1L-interacting protein reveals cotranslational quality control in mitochondria.

Cellular proteostasis requires transport of polypeptides across membranes. Although defective transport processes trigger cytosolic rescue and quality control mechanisms that clear translocases and membranes from unproductive cargo, proteins that are synthesized within mitochondria are not accessible to these mechanisms. Mitochondrial-encoded proteins are inserted cotranslationally into the inner membrane by the conserved insertase OXA1L.