9JCO

Cryo-EM structure of the proton-sensing GPCR (GPR4)-Gs protein complex at pH 6.5

これはPDB形式変換不可エントリーです。

9JCO の概要

• エントリーDOI: 10.2210/pdb9jco/pdb
• EMDBエントリー: 61370
• 分子名称: Guanine nucleotide-binding protein G(s) subunit alpha, Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1, Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2, ... (8 entities in total)
• 機能のキーワード: cryo-em, gpcr, proton-sensing, gpr4, ph 6.5, gs, complex, signaling protein
• 由来する生物種: Homo sapiens; 詳細
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 162410.65

構造登録者

You, C.,Xu, H.E.,Jiang, Y. (登録日: 2024-08-30, 公開日: 2025-07-09)

主引用文献

You, C.,Guo, S.,Zhang, T.,He, X.,Gao, T.,Xin, W.,Zhu, Z.,Lu, Y.,Xu, Y.,Li, Z.,Zhang, Y.,Cheng, X.,Jiang, Y.,Xie, X.,Xu, H.E.
Molecular mechanism of pH sensing and activation in GPR4 reveals proton-mediated GPCR signaling.
Cell Discov, 11:59-59, 2025

PubMed Abstract: Maintaining pH homeostasis is critical for cellular function across all living organisms. Proton-sensing G protein-coupled receptors (GPCRs), particularly GPR4, play a pivotal role in cellular responses to pH changes. Yet, the molecular mechanisms underlying their proton sensing and activation remain incompletely understood. Here we present high-resolution cryo-electron microscopy structures of GPR4 in complex with G proteins under physiological and acidic pH conditions. Our structures reveal an intricate proton-sensing mechanism driven by a sophisticated histidine network in the receptor's extracellular domain. Upon protonation of key histidines under acidic conditions, a remarkable conformational cascade is initiated, propagating from the extracellular region to the intracellular G protein-coupling interface. This dynamic process involves precise transmembrane helix rearrangements and conformational shifts of conserved motifs, mediated by strategically positioned water molecules. Notably, we discovered a bound bioactive lipid, lysophosphatidylcholine, which has positive allosteric effects on GPR4 activation. These findings provide a comprehensive framework for understanding proton sensing in GPCRs and the interplay between pH sensing and lipid regulation, offering insights into cellular pH homeostasis and potential therapies for pH-related disorders.

PubMed: 40555728
DOI: 10.1038/s41421-025-00807-y

実験手法

ELECTRON MICROSCOPY (2.36 Å)