GPRC5B contains a signal peptide and seven transmembrane alpha-helices, which is a hallmark of G protein-coupled receptors (GPCRs). GPRC5B mRNA is widely expressed in peripheral and central tissues with highest abundance in kidney, pancreas, and testis. Both GPRC5A and GPRC5B have short extracellular amino-terminal domains (ATDs) that contrast the very long ATDs characterizing the other receptors currently assigned to the family C group of GPCRs.