Figure 4.

Regulation of OXPHOS by estrogen. Estrogen can regulate OXPHOS in several different manners. First, estrogen receptor (ER)-mediated classical genomic action regulates several nuclear DNA-encoded OXPHOS-related genes. Second, estrogen receptors found on mtDNA may regulate mtDNA-encoded OXPHOS-related genes, which can also be regarded as a kind of genomic action. Third, estrogen can affect OXPHOS through nongenomic action. This mode of action is mediated either by a small portion of ER (as a nuclear receptor) localizing at the plasma membrane or by a different membrane receptor called GPER (G-protein coupled estrogen receptor), also known as GPR30. Lastly, a receptor-independent mechanism is reported. In this mechanism, estrogen incorporated in the mitochondrial membrane alters its microviscosity, eventually affecting the activities of mitochondrial respiratory chain (MRC) complexes.