G protein-coupled receptor 119, also called glucose-dependent insulinotropic receptor, member of the class A family of seven-transmembrane G protein-coupled receptors
GPR119 is activated by oleoylethanolamide (OEA), a naturally occurring bioactive lipid with hypophagic and anti-obesity effects. Immunohistochemistry and double-immunofluorescence studies revealed the predominant GPR119 localization in pancreatic polypeptide (PP)-cells of islets. In addition, GPR119 expression is elevated in islets of obese hyperglycemic mice as compared to control islets, suggesting a possible involvement of this receptor in the development of obesity and diabetes. GPR119 has a significant sequence similarity with the members of the endothelial differentiation gene family. All GPCRs have a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes.