Niacin receptor 2, also known as NIACR2 or GPR109B, is a protein which in humans is encoded by the NIACR2 gene.
GPR109B is a low affinity receptor for nicotinic acid (niacin) and is a member of the nicotinic acid receptor family of G protein-coupled receptors (the other identified member being GPR109A).
GPR109B is a Gi /Go protein-coupled receptor with low affinity for nicotinic acid.