Class C GPCR

7 transmembrane receptor (metabotropic glutamate family)
Identifiers
Symbol	7tm_3
Pfam	PF00003
InterPro	IPR000337
PROSITE	PDOC00754
TCDB	9.A.14
OPM superfamily	6
OPM protein	4or2
CDD	cd13953
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The class C G-protein-coupled receptors (InterPro: IPR000337) are a class of G-protein coupled receptors that include the metabotropic glutamate receptors (InterPro: IPR000162) and several additional receptors.^[1]

Structurally they are composed of four elements; an N-terminal signal sequence; a large hydrophilic extracellular agonist-binding region containing several conserved cysteine residues which could be involved in disulphide bonds; a shorter region containing seven transmembrane domains; and a C-terminal cytoplasmic domain of variable length.^[1] This protein family includes metabotropic glutamate receptors, the extracellular calcium-sensing receptors, the gamma-amino-butyric acid (GABA) type B receptors, and the vomeronasal type-2 receptors.

Subfamilies

Calcium-sensing receptor-related

• extracellular calcium-sensing receptor-related InterPro: IPR000068
  • Calcium-sensing receptor (CASR)
  • GPRC6A (GPRC6A)

GABA_B receptors

• GABA_B receptor (gamma-aminobutyric acid) InterPro: IPR002455
  • GABA_B receptor 1 (GABBR1)
  • GABA_B receptor 2 (GABBR2)

Metabotropic glutamate receptors

• Metabotropic glutamate receptors (mGluR) InterPro: IPR000162
  • mGluR₁ (GRM1)
  • mGluR₂ (GRM2)
  • mGluR₃ (GRM3)
  • mGluR₄ (GRM4)
  • mGluR₅ (GRM5)
  • mGluR₆ (GRM6)
  • mGluR₇ (GRM7)
  • mGluR₈ (GRM8)

RAIG

• Retinoic acid-inducible orphan G protein-coupled receptors (RAIG)
  • RAIG₁ (GPRC5A)
  • RAIG₂ (GPRC5B)
  • RAIG₃ (GPRC5C)
  • RAIG₄ (GPRC5D)

Taste receptors

• Taste receptor
  • Taste receptor, type 1, member 1 (TAS1R1)
  • Taste receptor, type 1, member 2 (TAS1R2)
  • Taste receptor, type 1, member 3 (TAS1R3)

Orphan

• Class C Orphan receptors
  • GPR158 (GPR158)
  • GPR179 (GPR179)
  • GPR156 (GPR156)

Other

• Bride of sevenless protein InterPro: IPR002956
• Vomeronasal receptor, type 2 InterPro: IPR004073

References

1. Bräuner-Osborne H, Wellendorph P, Jensen AA (2007). "Structure, pharmacology and therapeutic prospects of family C G-protein coupled receptors". Curr Drug Targets. 8 (1): 169–84. doi:10.2174/138945007779315614. PMID 17266540.