Cytochrome c oxidase subunit 6A2, mitochondrial (COX6A2)

Cytochrome c oxidase subunit 6A2, mitochondrial (COX6A2), is a nuclear-encoded structural subunit of cytochrome c oxidase (Complex IV), the final enzyme of the mitochondrial electron transport chain responsible for the transfer of electrons from cytochrome c to molecular oxygen and generation of the proton gradient that drives ATP synthesis[1][3][4]. COX6A2 is specifically the heart/muscle isoform of subunit VIa, expressed mainly in striated muscle, including cardiac and skeletal muscle cells; a different isoform (COX6A1) is present in other tissues[1][3]. While the catalytic core of the complex is mitochondrial-encoded, COX6A2 and other nuclear-encoded subunits are believed to contribute to complex assembly, stability, and possibly its regulation[1][3]. Functionally, COX6A2 is essential for normal mitochondrial structure, ATP generation, and calcium handling in myocytes[2], and its deficiency can trigger pathological myocardial remodeling, mitochondrial dysfunction, and increased oxidative stress[2]. In pancreatic islet β-cells, COX6A2 overexpression promotes mitochondria-dependent apoptosis via VDAC1/Bax-mediated cytochrome c release, relevant for β-cell loss in diabetes[5]. Clinically, both deficiency and overactivity of COX6A2 are linked to disease: its loss causes cardiac dysfunction and energy failure in muscle, while aberrant expression enhances apoptosis in diabetes[5]. COX6A2 is targeted indirectly by drugs (such as L-carnitine and trimetazidine) to restore metabolic function in disease models[2].

Other names

COX6A2COX VIa-MCOX6ACOX6AHCOXVIAHCytochrome c oxidase polypeptide VIa-heartCytochrome c oxidase subunit VIA-muscleCytochrome c oxidase subunit VIa polypeptide 2MC4DN18

Modulation of energy metabolism (via fatty acid β-oxidation or glycolysis enhancement)[2]; Promotion or blockade of mitochondria-dependent apoptosis (via VDAC1/Bax/cytochrome c route)[5]