Detailed definition
Estrogen receptor alpha (ERα), encoded by the ESR1 gene, is one of two principal nuclear estrogen receptors (the other being ERβ, encoded by ESR2). ERα binds estradiol and other ligands, dimerizes, translocates to the nucleus, and modulates transcription of estrogen-responsive genes. It also mediates non-genomic membrane signaling. Tissue distribution: uterus (endometrium and myometrium), breast (epithelium), ovary, liver (lipid metabolism), hypothalamus (thermoregulation, feedback), pituitary (LH/FSH regulation), and bone. ERα activity in the breast is the basis for HR-positive breast cancer responsiveness to antiestrogens. ERα activation in the endometrium drives the proliferation that progesterone counterbalances. ERα in the hypothalamic preoptic area is central to thermoregulation, and its withdrawal underlies vasomotor symptoms.
Why it matters in menopause
Estrogen replacement essentially restores ERα signaling to a more youthful range. The tissue-specific effects of ERα explain why estrogen has so many simultaneous benefits in menopause — bone, vasomotor, mood, vaginal — and also why endometrial protection is needed in the uterus.
Related terms
Sources
External references: Wikipedia.