[ESR2_HUMAN] Nuclear hormone receptor. Binds estrogens with an affinity similar to that of ESR1, and activates expression of reporter genes containing estrogen response elements (ERE) in an estrogen-dependent manner. Isoform beta-cx lacks ligand binding ability and has no or only very low ere binding activity resulting in the loss of ligand-dependent transactivation ability. DNA-binding by ESR1 and ESR2 is rapidly lost at 37 degrees Celsius in the absence of ligand while in the presence of 17 beta-estradiol and 4-hydroxy-tamoxifen loss in DNA-binding at elevated temperature is more gradual.
The R,R enantiomer of 5,11-cis-diethyl-5,6,11,12-tetrahydrochrysene-2,8-diol (THC) exerts opposite effects on the transcriptional activity of the two estrogen receptor (ER) subtypes, ER alpha and ER beta. THC acts as an ER alpha agonist and as an ER beta antagonist. We have determined the crystal structures of the ER alpha ligand binding domain (LBD) bound to both THC and a fragment of the transcriptional coactivator GRIP1, and the ER beta LBD bound to THC. THC stabilizes a conformation of the ER alpha LBD that permits coactivator association and a conformation of the ER beta LBD that prevents coactivator association. A comparison of the two structures, taken together with functional data, reveals that THC does not act on ER beta through the same mechanisms used by other known ER antagonists. Instead, THC antagonizes ER beta through a novel mechanism we term 'passive antagonism'.
Structural characterization of a subtype-selective ligand reveals a novel mode of estrogen receptor antagonism.,Shiau AK, Barstad D, Radek JT, Meyers MJ, Nettles KW, Katzenellenbogen BS, Katzenellenbogen JA, Agard DA, Greene GL Nat Struct Biol. 2002 May;9(5):359-64. PMID:11953755
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