4-Hydroxytamoxifen binds to and deactivates the estrogen-related receptor gamma.
The estrogen-related receptors (ERR alpha, ERR beta, and ERR gamma) form a family of orphan nuclear receptors that share significant amino acid identity with the estrogen receptors, but for which physiologic roles remain largely unknown. By using a peptide sensor assay, we have identified the stilbenes diethylstilbestrol (DES), tamoxifen (TAM), and 4-hydroxytamoxifen (4-OHT) as high-affinity ligands for ERR gamma. In direct binding assays, 4-OHT had a K(d) value of 35 nM, and both DES and TAM displaced radiolabeled 4-OHT with K(i) values of 870 nM. In cell-based assays, 4-OHT binding caused a dissociation of the complex between ERR gamma and the steroid receptor coactivator-1, and led to an inhibition of the constitutive transcriptional activity of ERR gamma. ERR alpha did not bind 4-OHT, but replacing a single amino acid predicted to be in the ERR alpha ligand-binding pocket with the corresponding ERR gamma residue allowed high-affinity 4-OHT binding. These results demonstrate the existence of high-affinity ligands for the ERR family of orphan receptors, and identify 4-OHT as a molecule that can regulate the transcriptional activity of ERR gamma.
Coward
P
P
Tularik, Inc., 2 Corporate Drive, South San Francisco, CA 94080, USA. pcoward@tularik.com
Lee
D
D
Hull
M V
MV
Lehmann
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D004054:Diethylstilbestrol / Q000378:metabolism; D004965:Estrogen Antagonists / Q000378:metabolism*; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D006801:Humans; D008969:Molecular Sequence Data; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C425824:estrogen receptor gamma; D013629:Tamoxifen; C016601:afimoxifene; D004054:Diethylstilbestrol