Structure—Function Relationships in G Protein-Coupled Receptors: Ligand Binding and Receptor Activation

Abstract

G protein-coupled receptors (GPCRs) are integral membrane proteins that form the fourth largest superfamily in the human genome, with more than 800 genes identified to date (1,2). Many of these receptors play key physiological roles, and several pathologies have been associated with receptor functional abnormalities (3,4). Therefore, GPCRs represent important targets for drug design within pharmaceutical companies (5). Indeed, GPCRs mediate the effect of numerous ligands, including neurotransmitters, chemo-attractants, hormones, cytokines, and sensory stimuli such as photons and odorants.