New Binding Sites, New Opportunities for GPCR Drug Discovery

G protein-coupled receptors (GPCRs) mediate numerous physiological activities in the body. Recently resolved crystal structures reveal an increasing number of allosteric ligands. In this review, we systematically cluster the locations of these binding sites from the extracellular, the transmembrane, to the intracellular regions. We also analyze the protein–ligand interactions between these allosteric ligands and their corresponding GPCRs