E-type prostanoid receptor 4 (EP4) is responsible for mediating the effects of prostaglandin E2 (PGE2), an endogenous molecule involved in several biological processes such as pain, fever, regulation of vascular tone, renal function, mucosal integrity, inflammation, angiogenesis and tumor growth. In turn, EP4 receptor is involved in anti-inflammatory, anti-thrombotic, vasoprotective effects, adverse tumor-promoting and pro-angiogenic roles^1,2.

EP4 mRNA expression is detected in the gastrointestinal tract, uterus, hematopoietic tissues and skin. High expression is also found in most immune cell types. The EP receptors activate various signaling pathways. EP4 is a G_s coupled receptor, which activates adenylate cyclase and activates intracellular cyclic adenylyl monophosphate (cAMP) production^1,2.

The EP receptors contain an aspartate in the second transmembrane domain, which is involved in receptor-ligand interaction and conserved cysteine residues in the second and third extracellular domains, which form a disulfide bonds critical for stabilizing the receptor and for ligand binding³.