Download MendeleyMolecular basis of proton sensing by G protein-coupled receptors.
Howard, M.K., Hoppe, N., Huang, X.P., Mitrovic, D., Billesbolle, C.B., Macdonald, C.B., Mehrotra, E., Rockefeller Grimes, P., Trinidad, D.D., Delemotte, L., English, J.G., Coyote-Maestas, W., Manglik, A.(2025) Cell 188: 671
- PubMed: 39753132
- DOI: https://doi.org/10.1016/j.cell.2024.11.036
- Primary Citation of Related Structures:
9BHL, 9BHM, 9BI6, 9BIP - PubMed Abstract:
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.
Organizational Affiliation:
Tetrad graduate program, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Bioengineering and Therapeutic Science, University of California, San Francisco, San Francisco, CA 94143, USA.
