The human gene encoding the QRFP receptor (QRFPR, also known as the peptide P518 receptor), previously designated as an orphan GPCR receptor was identified in 2001 by Lee et al. from a hypothalamus cDNA library [7]. However, the reported cDNA (AF411117) is a chimera with bases 1-127 derived from chromosome 1 and bases 155-1368 derived from chromosome 4. When corrected, QRFPR (also referred to as SP9155 or AQ27) encodes a 431 amino acid protein that shares sequence similarities in the transmembrane spanning regions with other peptide receptors. These include neuropeptide FF2 (38%), neuropeptide Y₂ (37%) and galanin Gal₁ (35%) receptors.

The orphan receptor GPR83 (9NYM4) shows sequence similarities with the QRFP receptor, as well as with the NPFF1, NPFF2, and PrRP receptors.

* Key recommended reading is highlighted with an asterisk

* Fukusumi S, Fujii R, Hinuma S. (2006) Recent advances in mammalian RFamide peptides: the discovery and functional analyses of PrRP, RFRPs and QRFP. Peptides, 27 (5): 1073-86. [PMID:16500002]

1. Chartrel N, Dujardin C, Anouar Y, Leprince J, Decker A, Clerens S, Do-Régo JC, Vandesande F, Llorens-Cortes C, Costentin J et al.. (2003) Identification of 26RFa, a hypothalamic neuropeptide of the RFamide peptide family with orexigenic activity. Proc. Natl. Acad. Sci. U.S.A., 100 (25): 15247-52. [PMID:14657341]

2. Fukusumi S, Yoshida H, Fujii R, Maruyama M, Komatsu H, Habata Y, Shintani Y, Hinuma S, Fujino M. (2003) A new peptidic ligand and its receptor regulating adrenal function in rats. J. Biol. Chem., 278 (47): 46387-95. [PMID:12960173]

3. Georgsson J, Bergström F, Nordqvist A, Watson MJ, Blundell CD, Johansson MJ, Petersson AU, Yuan ZQ, Zhou Y, Kristensson L et al.. (2014) GPR103 antagonists demonstrating anorexigenic activity in vivo: design and development of pyrrolo[2,3-c]pyridines that mimic the C-terminal Arg-Phe motif of QRFP26. J. Med. Chem., 57 (14): 5935-48. [PMID:24937104]

4. Georgsson J, Bergström F, Nordqvist A, Watson MJ, Blundell CD, Johansson MJ, Petersson AU, Yuan ZQ, Zhou Y, Kristensson L et al.. (2015) Correction to GPR103 Antagonists Demonstrating Anorexigenic Activity in Vivo: Design and Development of Pyrrolo[2,3-c]pyridines That Mimic the C-Terminal Arg-Phe Motif of QRFP26. J. Med. Chem., 58 (9): 4086. [PMID:25875054]

5. Jiang Y, Luo L, Gustafson EL, Yadav D, Laverty M, Murgolo N, Vassileva G, Zeng M, Laz TM, Behan J et al.. (2003) Identification and characterization of a novel RF-amide peptide ligand for orphan G-protein-coupled receptor SP9155. J. Biol. Chem., 278 (30): 27652-7. [PMID:12714592]

6. Kuc RE, Mitchell JD, Davenport AD. (2006) The novel ligand [125I]-QRFP43 reveals a remarkably discrete distribution of the orphan receptor GPR103 in human adrenal. Proceedings of the British Pharmacological Society, 4 (2): abst186.

7. Lee DK, Nguyen T, Lynch KR, Cheng R, Vanti WB, Arkhitko O, Lewis T, Evans JF, George SR, O'Dowd BF. (2001) Discovery and mapping of ten novel G protein-coupled receptor genes. Gene, 275: 83-91. [PMID:11574155]

8. Neveu C, Lefranc B, Tasseau O, Do-Rego JC, Bourmaud A, Chan P, Bauchat P, Le Marec O, Chuquet J, Guilhaudis L et al.. (2012) Rational design of a low molecular weight, stable, potent, and long-lasting GPR103 aza-β3-pseudopeptide agonist. J. Med. Chem., 55 (17): 7516-24. [PMID:22800498]

9. Takayasu S, Sakurai T, Iwasaki S, Teranishi H, Yamanaka A, Williams SC, Iguchi H, Kawasawa YI, Ikeda Y, Sakakibara I et al.. (2006) A neuropeptide ligand of the G protein-coupled receptor GPR103 regulates feeding, behavioral arousal, and blood pressure in mice. Proc. Natl. Acad. Sci. U.S.A., 103 (19): 7438-43. [PMID:16648250]