MAS Related GPR Member X4 (MRGPRX4)

Dong et al. (2001) identified, in the mouse and human genomes, a family of G protein-coupled receptors (GPCRs) related to the MAS1 oncogene, including MRGX4. Several pseudogenes were also identified. The predicted MRG proteins contain transmembrane, extracellular, and cytoplasmic domains. A subset of MRGs was expressed in specific subpopulations of sensory neurons that detect painful stimuli. The expression patterns of these genes thus revealed an unexpected degree of molecular diversity among nociceptive neurons. Some MRGs could be specifically activated in heterologous cells by RFamide neuropeptides such as NPFF and NPAF, which are analgesic in vivo. The authors concluded that MRGs may regulate nociceptor function and/or development, including the sensation or modulation of pain.