pyroglutamylated RFamide peptide receptor, member of the class A family of seven-transmembrane G protein-coupled receptors
26RFa, also known as QRFP (Pyroglutamylated RFamide peptide), is a 26-amino acid residue peptide that belongs to a family of neuropeptides containing an Arg-Phe-NH2 (RFamide) motif at its C-terminus. 26Rfa/QRFP exerts similar orexigenic activity including the regulation of feeding behavior in mammals. It is the ligand for G-protein coupled receptor 103 (GPR103), which is predominantly expressed in paraventricular (PVN) and ventromedial (VMH) nuclei of the hypothalamus. GPR103 shares significant protein sequence homology with orexin receptors (OX1R and OX2R), which have recently shown to produce a neuroprotective effect in Alzheimer's disease by forming a functional heterodimer with GPR103.
Comment:based on the structures of some class A family members with bound ligands (peptides or chemicals), agonists, or antagonists
Comment:Small-molecule chemical ligands tend to bind deeper within the receptor core, compared to a peptide ligand neurotensin, which binds towards the extracellular surface of its receptor.
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