Asymmetric allostery in estrogen receptor-α homodimers drives responses to the ensemble of estrogens in the hormonal milieu

• 成果类型: Article
• 署名作者: Min, Charles K.; Nwachukwu, Jerome C.; Hou, Yingwei; Russo, Robin J.; Papa, Alexandra; Min, Jian; Peng, Rouming; Kim, Sung Hoon; Ziegler, Yvonne; Rangarajan, Erumbi S.; Izard, Tina; Katzenellenbogen, Benita S.; Katzenellenbogen, John A.; Nettles, Kendall W.
• 署名单位: Scripps Research Institute; University of Illinois System; University of Illinois Urbana-Champaign; University of Illinois System; University of Illinois Urbana-Champaign; State University System of Florida; Florida Atlantic University; Hubei University; University of Illinois System; University of Illinois Urbana-Champaign
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13468
• DOI: 10.1073/pnas.2321344121
• 发表日期: 2024-06-11
• 关键词: dna-binding; structural basis; antagonism; DYNAMICS; subunit; 27-hydroxycholesterol; mechanisms; software; affinity; MODEL

摘要

The estrogen receptor -alpha (ER) is thought to function only as a homodimer but responds to a variety of environmental, metazoan, and therapeutic estrogens at subsaturating doses, supporting binding mixtures of ligands as well as dimers that are only partially occupied. Here, we present a series of flexible ER ligands that bind to receptor dimers with individual ligand poses favoring distinct receptor conformations-receptor conformational heterodimers-mimicking the binding of two different ligands. Molecular dynamics simulations showed that the pairs of different ligand poses changed the correlated motion across the dimer interface to generate asymmetric communication between the dimer interface, the ligands, and the surface binding sites for epigenetic regulatory proteins. By examining the binding of the same ligand in crystal structures of ER in the agonist vs. antagonist conformers, we also showed that these allosteric signals are bidirectional. The receptor conformer can drive different ligand binding modes to support agonist vs. antagonist activity profiles, a revision of ligand binding theory that has focused on unidirectional signaling from the ligand to the coregulator binding site. We also observed differences in the allosteric signals between ligand and coregulator binding sites in the monomeric vs. dimeric receptor, and when bound by two different ligands, states that are physiologically relevant. Thus, ER conformational heterodimers integrate two different ligand - regulated activity profiles, representing different modes for ligand - dependent regulation of ER activity.