prostaglandin D2 receptor, member of the class A family of seven-transmembrane G protein-coupled receptors
Prostaglandin D2 receptor, also known as CRTH2, is a chemoattractant G-protein coupled receptor expressed on T helper type 2 cells that binds prostaglandin D2 (PGD2). PGD2 functions as a mast cell-derived mediator to trigger asthmatic responses and also causes vasodilation. PGD2 exerts its inflammatory effects by binding to two G-protein coupled receptors, the D-type prostanoid receptor (DP) and PD2R2 (CRTH2). PD2R2 couples to the G protein G(i/o) type which leads to a reduction in intracellular cAMP levels and an increase in intracellular calcium. PD2R2 is involved in mediating chemotaxis of Th2 cells, eosinophils, and basophils generated during allergic inflammatory processes. CRTH2 (PD2R2), but not DP receptor, undergoes agonist-induced internalization which is one of key processes that regulates the signaling of the GPCR.