PET117 Modulates Mitochondrial-encoded COX1 Translation by stabilizing TACO1

Abstract

Abstract Mitochondria are the most important organelles in energy metabolism. Complexes of the mitochondrial oxidative phosphorylation system (OXPHOS) are formed by proteins of dual origin synthesized in the cytosol or mitochondria. The mechanisms underlying specific translation by mitoribosomes in mammals are largely unknown. Here, we report a chaperone protein of cytochrome c oxidase (COX) assembly, PET117 plays a critical role in the synthesis of mitochondrial-encoded COX1 protein in human cells. Lack of PET117 impaired mitochondrial function via suppression of mitochondrial oxygen consumption rate (OCR), probably due to reduced stability of TACO1, a COX1 translational activator. We uncovered the role of PET117 in mitochondrial regulation and a novel PET117-TACO1 axis modulating mitochondrial gene expression.