G protein-coupled receptor 31, member of the class A family of seven-transmembrane G protein-coupled receptors
GPR31, also known as 12-(S)-HETE receptor, is a high-affinity receptor for 12-(S)-hydroxy-5,8,10,14-eicosatetraenoic acid. Phylogenetic analysis showed that GPR31 and oxoeicosanoid receptor 1 (OXER1, GPR170) are the most closely related receptors to the hydroxycarboxylic acid receptor family (HCARs). GPR31, like OXER1, activates the ERK1/2 (MAPK3/MAPK1) pathway of intracellular signaling, but unlike the OXER1, does not cause increase in the cytosolic calcium level. GPR31 is also shown to activate NFkB. 12-(S)-HETE is a 12-lipoxygenase metabolite of arachidonic acid produced by mammalian platelets and tumor cells. It promotes tumor cells adhesion to endothelial cells and subendothelial matrix, which is a critical step for metastasis.