Activation and signaling mechanism revealed by GPR119-Gs complex structures

Agonists selectively targeting cannabinoid receptor-like G-protein-coupled receptor (GPCR) GPR119 hold promise for treating metabolic disorders while avoiding unwanted side effects. Here we present the cryo-electron microscopy (cryo-EM) structures of the human GPR119-G(s) signaling complexes bound to AR231453 and MBX-2982, two representative agonists reported for GPR119. The structures reveal a one-amino acid shift of the conserved proline residue of TM5 that forms an outward bulge, opening up a hydrophobic cavity between TM4 and TM5 at the middle of the membrane for its endogenous ligands-monounsaturated lipid metabolites. In addition, we observed a salt bridge between ICL1 of GPR119 and G beta(s). Disruption of the salt bridge eliminates the cAMP production of GPR119, indicating an important role of G beta(s) in GPR119-mediated signaling. Our structures, together with mutagenesis studies, illustrate the conserved binding mode of the chemically different agonists, and provide insights into the conformational changes in receptor activation and G protein coupling. Agonists selectively targeting GPR119 hold promise for treating metabolic disorders. Here, authors reveal that GPR119 adopts a non-canonical consensus structural scaffold with an extended ligand-binding pocket for chemically different agonists.

Automated summary

This study reveals that GPR119 adopts a non-canonical consensus structural scaffold and possesses an extended ligand-binding pocket for chemically different agonists.