Minute-scale persistence of a GPCR conformation state triggered by non-cognate G protein interactions primes signaling

Despite the crowded nature of the cellular milieu, ligand-GPCR-G protein interactions are traditionally viewed as spatially and temporally isolated events. In contrast, recent reports suggest the spatial and temporal coupling of receptor-effector interactions, with the potential to diversify downstream responses. In this study, we combine protein engineering of GPCR-G protein interactions with affinity sequestration and photo-manipulation of the crucial G alpha C terminus, to demonstrate the temporal coupling of cognate and non-cognate G-protein interactions through priming of the GPCR conformation. We find that interactions of the Gas and G alpha q C termini with the beta(2)-adrenergic receptor (beta(2)-AR), targeted at the G-protein-binding site, enhance Gs activation and cyclic AMP levels. beta(2)-AR-Ga C termini interactions alter receptor conformation, which persists for similar to 90 s following G alpha C terminus dissociation. Noncognate G-protein expression levels impact cognate signaling in cells. Our study demonstrates temporal allostery in GPCRs, with implications for the modulation of downstream responses through the canonical G-protein-binding interface.