ジャーナル: Nat Struct Mol Biol / 年: 2022 タイトル: Structural insight into apelin receptor-G protein stoichiometry. 著者: Yang Yue / Lier Liu / Li-Jie Wu / Yiran Wu / Ling Wang / Fei Li / Junlin Liu / Gye-Won Han / Bo Chen / Xi Lin / Rebecca L Brouillette / Émile Breault / Jean-Michel Longpré / Songting Shi / ...著者: Yang Yue / Lier Liu / Li-Jie Wu / Yiran Wu / Ling Wang / Fei Li / Junlin Liu / Gye-Won Han / Bo Chen / Xi Lin / Rebecca L Brouillette / Émile Breault / Jean-Michel Longpré / Songting Shi / Hui Lei / Philippe Sarret / Raymond C Stevens / Michael A Hanson / Fei Xu / 要旨: The technique of cryogenic-electron microscopy (cryo-EM) has revolutionized the field of membrane protein structure and function with a focus on the dominantly observed molecular species. This report ...The technique of cryogenic-electron microscopy (cryo-EM) has revolutionized the field of membrane protein structure and function with a focus on the dominantly observed molecular species. This report describes the structural characterization of a fully active human apelin receptor (APJR) complexed with heterotrimeric G protein observed in both 2:1 and 1:1 stoichiometric ratios. We use cryo-EM single-particle analysis to determine the structural details of both species from the same sample preparation. Protein preparations, in the presence of the endogenous peptide ligand ELA or a synthetic small molecule, both demonstrate these mixed stoichiometric states. Structural differences in G protein engagement between dimeric and monomeric APJR suggest a role for the stoichiometry of G protein-coupled receptor- (GPCR-)G protein coupling on downstream signaling and receptor pharmacology. Furthermore, a small, hydrophobic dimer interface provides a starting framework for additional class A GPCR dimerization studies. Together, these findings uncover a mechanism of versatile regulation through oligomerization by which GPCRs can modulate their signaling.