National Institutes of Health/National Cancer Institute (NIH/NCI)
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
5T32GM139786
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
F31HL164045
米国
引用
ジャーナル: Cell / 年: 2025 タイトル: Molecular basis of proton sensing by G protein-coupled receptors. 著者: Matthew K Howard / Nicholas Hoppe / Xi-Ping Huang / Darko Mitrovic / Christian B Billesbølle / Christian B Macdonald / Eshan Mehrotra / Patrick Rockefeller Grimes / Donovan D Trinidad / ...著者: Matthew K Howard / Nicholas Hoppe / Xi-Ping Huang / Darko Mitrovic / Christian B Billesbølle / Christian B Macdonald / Eshan Mehrotra / Patrick Rockefeller Grimes / Donovan D Trinidad / Lucie Delemotte / Justin G English / Willow Coyote-Maestas / Aashish Manglik / 要旨: Three proton-sensing G protein-coupled receptors (GPCRs)-GPR4, GPR65, and GPR68-respond to extracellular pH to regulate diverse physiology. How protons activate these receptors is poorly understood. ...Three proton-sensing G protein-coupled receptors (GPCRs)-GPR4, GPR65, and GPR68-respond to extracellular pH to regulate diverse physiology. How protons activate these receptors is poorly understood. We determined cryogenic-electron microscopy (cryo-EM) structures of each receptor to understand the spatial arrangement of proton-sensing residues. Using deep mutational scanning (DMS), we determined the functional importance of every residue in GPR68 activation by generating ∼9,500 mutants and measuring their effects on signaling and surface expression. Constant-pH molecular dynamics simulations provided insights into the conformational landscape and protonation patterns of key residues. This unbiased approach revealed that, unlike other proton-sensitive channels and receptors, no single site is critical for proton recognition. Instead, a network of titratable residues extends from the extracellular surface to the transmembrane region, converging on canonical motifs to activate proton-sensing GPCRs. Our approach integrating structure, simulations, and unbiased functional interrogation provides a framework for understanding GPCR signaling complexity.