Mammalian mitochondrial electron transport chain subunit composition of oxidative phosphorylation (OXPHOS) complexes encoded by mtDNA and nuclear DNA. MtDNA, mitochondrial DNA; NAD, nicotinamide adenine dinucleotide; FAD, flavin adenine dinucleotide; CoQ10, coenzyme Q10; Cyt C, cytochrome C; ADP, adenosine diphosphate; ATP, adenosine triphosphate; NRF, nuclear respiratory factor; PGC1α, peroxisome proliferator-activated receptor γ coactivator 1α; AMPK, adenosine monophosphate-activated protein kinase; SIRT3, sirtuin 3.