Heterotrimetic G proteins consist of four subfamilies (G， G， G， and G) that mediate signaling via G-protein-coupled receptors (GPCRs)， principally by receptors binding Gα C termini. G-protein-coupling profiles govern GPCR-induced cellular responses， yet receptor sequence selectivity determinants remain elusive. Here， we systematically quantified ligand-induced interactions between 148 GPCRs and all 11 unique Gα subunit C termini. For each receptor， we probed chimeric Gα subunit activation via a transforming growth factor-α (TGF-α) shedding response in HEK293 cells lacking endogenous G and G proteins， and complemented G-protein-coupling profiles through a NanoBiT-G-protein dissociation assay... More
Heterotrimetic G proteins consist of four subfamilies (G， G， G， and G) that mediate signaling via G-protein-coupled receptors (GPCRs)， principally by receptors binding Gα C termini. G-protein-coupling profiles govern GPCR-induced cellular responses， yet receptor sequence selectivity determinants remain elusive. Here， we systematically quantified ligand-induced interactions between 148 GPCRs and all 11 unique Gα subunit C termini. For each receptor， we probed chimeric Gα subunit activation via a transforming growth factor-α (TGF-α) shedding response in HEK293 cells lacking endogenous G and G proteins， and complemented G-protein-coupling profiles through a NanoBiT-G-protein dissociation assay. Interrogation of the dataset identified sequence-based coupling specificity features， inside and outside the transmembrane domain， which we used to develop a coupling predictor that outperforms previous methods. We used the predictor to engineer designer GPCRs selectively coupled to G. This dataset of fine-tuned signaling mechanisms for diverse GPCRs is a valuable resource for research in GPCR signaling.
