G-protein coupled receptor that binds to several ligands including the tryptophan metabolite kynurenic acid (KYNA), lysophosphatidic acid (LPA) or 5-hydroxyindoleacetic acid (5-HIAA) with high affinity, leading to rapid and transient activation of numerous intracellular signaling pathways.Plays a role in neutrophil recruitment to sites of inflammation and bacterial clearance through the major serotonin metabolite 5-HIAA that acts as a physiological ligand .Stimulates lipid metabolism, thermogenic, and anti-inflammatory gene expression in adipose tissue once activated by kynurenic acid.