Prostaglandin is a small molecule produced from arachidonic acid by the enzymes COX1, COX2 and PG synthase. PGE2 regulates various factors of inflammatory response, promoting local vasodilatation and attracting immune system cells to the site of the inflammation.nProstanoid EP3 Receptor, a member of the G-protein coupled receptor superfamily is one of four PGE2 receptors (EP1-EP4) and binds PGE2 with a higher affinity than other receptors of its class. Unlike EP2 and EP4, EP3 is not coupled to Gs and lacks cAMP activating functions. In contrast, most of its splice variants couple with Gi and inhibit adenylate cyclase activity1. EP3 binds prostaglandin in a GTP dependent manner. One of the receptor’s extracellular domains, ECII, can alter GTP effect on agonist binding and thus the receptor’s downstream intracellular signaling. ECII causes receptor conformational changes
