Proton perception and activation of a proton-sensing GPCR

GPR4 is a prototypical proton-sensing GPCR that belongs to Class A GPCRs. We reported the cryo-electron microscopy structures of human GPR4 in its apo inactive, antagonist-bound inactive, Gs-coupled, and Gi-coupled active states. Here, we present SDS-PAGE analysis results for the purified apo inactive GPR4, antagonist-bound inactive GPR4, Gs-coupled active GPR4, and Gi-coupled active GPR4.