Estrogen receptor
（重定向自Estradiol receptor）
![](/Images/godic/202501/11/PBB_Protein_ESR1_image2011.png")
![](/Images/godic/202501/11/Estrogen_receptor_beta_1U3S2011.png")
![The domain structures of ERα and ERβ, including some of the known phosphorylation sites involved in ligand-independent regulation.](/Images/godic/202501/11/Er_domains.svg2011.png")
![Nolvadex (tamoxifen) 20 mg](/Images/godic/202501/11/Nolvadex2011.jpg")
Estrogen receptors (ERs) are a group of proteins found inside and on cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of ER exist: nuclear estrogen receptors (ERα and ERβ), which are members of the nuclear receptor family of intracellular receptors, and membrane estrogen receptors (mERs) (GPER (GPR30), ER-X, and Gq-mER), which are mostly G protein-coupled receptors. This article refers to the former (ER).