G Protein Coupled Receptor 109B (GPR109B)

Chemokine receptors are members of the 7-transmembrane, G protein-coupled receptor (GPCR) family that recognize small proteins responsible for the directed migration of specific cell types.Sequence analysis predicted that the 387-amino acid, GPCR-type protein has significant homology to the B2 bradykinin receptor (BDKRB2) and to the thrombin receptor (F2R). Northern blot analysis revealed expression of a 2.3-kb HM74 transcript in peripheral blood mononuclear cells and neutrophils.The HM74 protein is a potential 7 transmembrane-spanning receptor that shares 96% identity with HM74A (GPR109A). HM74 expression in spleen, followed by lymphocytes and adipose tissue. Heart, placenta, prostate, and bone marrow showed lower expression, and little to no expression was detected in all other tissues examined.