p300 mediates functional synergism between AF-1 and AF-2 of estrogen receptor alpha and beta by interacting directly with the N-terminal A/B domains.
Fiche publication
Date publication
mai 2000
Journal
The Journal of biological chemistry
Auteurs
Membres identifiés du Cancéropôle Est :
Dr METZGER Daniel
Tous les auteurs :
Kobayashi Y, Kitamoto T, Masuhiro Y, Watanabe M, Kase T, Metzger D, Yanagisawa J, Kato S
Lien Pubmed
Résumé
Estrogen receptor (ER) alpha and beta mediate estrogen actions in target cells through transcriptional control of target gene expression. For 17beta-estradiol-induced transactivation, the N-terminal A/B domain (AF-1) and the C-terminal E/F domain (AF-2) of ERs are required. Ligand binding is considered to induce functional synergism between AF-1 and AF-2, but the molecular mechanism remains unknown. To clarify this synergism, we studied the role of reported AF-2 coactivators, p300/CREB binding protein, steroid receptor coactivator-1/transcriptional intermediary factor-2 (SRC-1/TIF2) family proteins and thyroid hormone receptor-associated protein-220/(vitamin D3 receptor-interacting protein- 205-(TRAP220/DRIP205) on the AF-1 activity in terms of synergism with the AF-2 function. We found that neither any of the SRC-1/TIF2 family coactivators nor TRAP220/DRIP205 is potent, whereas p300 potentiates the AF-1 function of both human ERalpha and human ERbeta. Direct interactions of p300 with the A/B domains of ERalpha and ERbeta were observed in an in vitro glutathione S-transferase pull-down assay in accordance with the interactions in yeast and mammalian two-hybrid assays. Furthermore, mutations in the p300 binding sites (56-72 amino acids in ERalpha and 62-72 amino acids in ERbeta) in the A/B domains caused a reduction in ligand-induced transactivation functions of both ERalpha and ERbeta. Thus, these findings indicate that ligand-induced functional synergism between AF-1 and AF-2 is mediated through p300 by its direct binding to the A/B regions of ERalpha and ERbeta.
Mots clés
Animals, Binding Sites, COS Cells, Carrier Proteins, metabolism, Estrogen Receptor alpha, Estrogen Receptor beta, Genes, Reporter, Histone Acetyltransferases, Humans, Mediator Complex Subunit 1, Mutation, Nuclear Proteins, genetics, Nuclear Receptor Coactivator 1, Nuclear Receptor Coactivator 2, Protein Binding, Receptors, Estrogen, metabolism, Trans-Activators, genetics, Transcription Factors, metabolism, Transcriptional Activation, genetics, Transfection
Référence
J. Biol. Chem.. 2000 May;275(21):15645-51