TABLE 2

Reported pairings of orphan receptors with cognate ligands reported by a single paper

Gene symbols are those approved by the HUGO Gene Nomenclature Committee (http://www.genenames.org/) (Seal et al., 2011). Where the phenotype of the knockout mouse has been published, this is indicated: Further information can be obtained from the IUPHAR Database (http://www.iuphar-db.org/) (Sharman et al., 2011) and the Mouse Genome Database at Mouse Genome Informatics (Eppig et al., 2012).

Putative Endogenous LigandApproved Human Gene SymbolKnockout MousePhenotype Reported
Class A
ChemerinGPR1YesNo
S1PGPR3YesYes
ProtonsGPR4YesYes
S1PGPR6YesYes
S1PGPR12YesYes
Nucleotides and CysLTs (leukotriene C4, leukotriene D4, UDP, UDP-galactose)GPR17YesYes
NAGlyGPR18No
12-(S)-HETEGPR31aNo
RvD1GPR32aNo
LPSGPR34YesYes
Kynurenic acid, 2-acyl LPAGPR35No
Neuropeptide head activatorbGPR37YesYes
Zn2+GPR39YesYes
l-α-LPIGPR55YesYes
ProtonsGPR65YesYes
ProtonsGPR68YesYes
CCL5 (RANTES)GPR75No
Medium-chain fatty acidsGPR84YesYes
LPAGPR87YesYes
OleoylethanolamideGPR119YesYes
ProtonsGPR132YesYes
OxysterolsGPR183YesYes
R-spondinsLGR4YesYes
R-spondinsLGR5YesYes
R-spondinsLGR6No
Ang-(1-7)MAS1YesYes
β-AlanineMRGPRDYesYes
BAM22MRGPRX1cNo
Cortistatin, PAMPMRGPRX2cNo
LPA, S1PP2RY10No
Class B
PhosphatidylserineBAI1No
C1q-like proteinsBAI3No
Decay accelerating factorCD97YesNo
Collagen type IIIGPR56YesYes
Neurexins, teneurin-2LPHN1YesYes
FLRT3LPHN3YesNo
Class C
Calcium, amino acids, and osteocalcinGPRC6AYesYes
  • a Pseudogene in mice.

  • b See discussion in text as to whether neuropeptide head activator is an endogenous ligand.

  • c Gene absent in mice.