Estrogen receptor and progesterone receptor (ER and PR)

Estrogen receptor and progesterone receptor are members of the nuclear receptor superfamily and function as ligand-activated transcription factors. The estrogen receptors (ERα and ERβ, encoded by the ESR1 and ESR2 genes, respectively) and the progesterone receptor (PR, encoded by the PGR gene, with isoforms PR-A and PR-B) bind their respective steroid hormones—estradiol (for ER) and progesterone (for PR). Upon hormone binding, these receptors dimerize and translocate to the cell nucleus, where they bind to specific DNA sequences (estrogen or progesterone response elements) and modulate the transcription of target genes involved in development, reproduction, cell proliferation, and differentiation. Both ER and PR are clinically important in oncology as therapeutic targets, especially in breast cancer, where their expression in tumor tissue informs prognosis and endocrine treatment selection. Drugs targeting these receptors include agonists, antagonists, and modulators widely used for contraception, hormone therapy, and cancer treatment[1][3][4][5][7].

Other names

ER and PREstrogen nuclear receptor and progesterone nuclear receptorESR1 (Estrogen receptor alpha), ESR2 (Estrogen receptor beta), PGR (Progesterone receptor)

Agonism: ligands bind and activate the receptor, promoting transcription of target genes Antagonism: ligands bind but block receptor activation (e.g., selective estrogen receptor modulators, antiestrogens, antiprogestins) Modulation: drugs can have tissue-selective agonist/antagonist effects (SERMs and SPRMs) Downregulation or degradation of the receptor