Mitochondrial estrogen receptors--new insights into specific functions.

Estrogen receptor (ER) alpha and ERbeta are present in mitochondria but little is known about their contribution to the overall constellation of cellular responses to 17beta-estradiol, which inhibits the early stages of apoptosis through membrane and mitochondrial, but not nuclear, ER signaling pathways. Whereas membrane ER signaling leading to inhibition of apoptosis involves the activation of protein kinase pathways, mitochondrial ER-mediated inhibition involves the direct and/or indirect activation of manganese superoxide dismutase by the mitochondrial ER.