Class C GPCR

7 transmembrane receptor (metabotropic glutamate family)
Identifiers
Symbol	7tm_3
Pfam	PF00003
InterPro	IPR000337
PROSITE	PDOC00754
Available protein structures: Pfam structures PDB RCSB PDB; PDBe PDBsum structure summary

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

Family C GPCRs have a large extracellular N-terminus which binds the orthosteric (endogenous) ligand. The shape of this domain is often likened to a clam. Several allosteric ligands to these receptors have been identified and these bind within the seven transmembrane region.

Subfamilies

Calcium-sensing receptor-related

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

GABA_B receptors

• GABA_B receptor (gamma-aminobutyric acid) IPR002455
  • GABA_B receptor 1 (GABBR1)
  • GABA_B receptor 2 (GABBR2)
  • GPR156 (GPR156)

Metabotropic glutamate receptors

• Metabotropic glutamate receptors (mGluR) 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)

Other

• Bride of sevenless protein IPR002956
• Vomeronasal receptor, type 2 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. 

Metabolites and
signaling molecules

Eicosanoid	CysLT (1, 2) · LTB4 (1, 2) · FPRL1 · OXE · Prostaglandin (DP (1, 2), EP (1, 2, 3, 4), FP) · Prostacyclin · Thromboxane
Other	Bile acid · Cannabinoid (CB1, CB2, GPR (18, 55, 119)) · EBI2 · Estrogen · Free fatty acid (1, 2, 3, 4) · Lactate  · Lysophosphatidic acid (1, 2, 3, 4, 5, 6)  · Lysophospholipid (1, 2, 3, 4, 5, 6, 7, 8) · Niacin (1, 2) · Oxoglutarate · PAF · Sphingosine-1-phosphate (1, 2, 3, 4, 5) · Succinate

Peptide

Neuropeptide	B/W (1, 2) · FF (1, 2) · S · Y (1, 2, 4, 5) · Neuromedin (B, U (1, 2)) · Neurotensin (1, 2)
Other	Anaphylatoxin (C3a, C5a) · Angiotensin (1, 2) · Apelin · Bombesin (BRS3, GRPR, NMBR) · Bradykinin (B1, B2) · Chemokine · Cholecystokinin (A, B) · Endothelin (A, B) · Formyl peptide (1, 2, 3) · FSH · Galanin (1, 2, 3) · GHB receptor · Gonadotropin-releasing hormone (1, 2) · Ghrelin · Kisspeptin · Luteinizing hormone/choriogonadotropin · MAS (1, 1L, D, E, F, G, X1, X2, X3, X4) · Melanocortin (1, 2, 3, 4, 5) · MCHR (1, 2) · Motilin · Opioid (Delta, Kappa, Mu, Nociceptin & Zeta, but not Sigma) · Orexin (1, 2) · Oxytocin · Prokineticin (1, 2) · Prolactin-releasing peptide · Relaxin (1, 2, 3, 4) · Somatostatin (1, 2, 3, 4, 5) · Tachykinin (1, 2, 3) · Thyrotropin · Thyrotropin-releasing hormone · Urotensin-II · Vasopressin (1A, 1B, 2)

Miscellaneous

Orphan	GPR (1, 3, 4, 6, 12, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 31, 32, 33, 34, 35, 37, 39, 42, 44, 45, 50, 52, 55, 61, 62, 63, 65, 68, 75, 77, 78, 81, 82, 83, 84, 85, 87, 88, 92, 101, 103, 109A, 109B, 119, 120, 132, 135, 137B, 139, 141, 142, 146, 148, 149, 150, 151, 152, 153, 160, 161, 162, 171, 173, 174, 176, 177, 182, 183)
Other	Adrenomedullin · Olfactory · Opsin (3, 4, 5, 1LW, 1MW, 1SW, RGR, RRH) · Protease-activated (1, 2, 3, 4) · SREB (1, 2, 3)

Class B: Secretin like

Orphan	GPR (56, 64, 97, 98, 110, 111, 112, 113, 114, 115, 116, 123, 124, 125, 126, 128, 133, 143, 144, 155, 157)
Other	Brain-specific angiogenesis inhibitor (1, 2, 3) · Cadherin (1, 2, 3) · Calcitonin · CALCRL · CD97 · Corticotropin-releasing hormone (1, 2) · EMR (1, 2, 3) · Glucagon (GR, GIPR, GLP1R, GLP2R) · Growth hormone releasing hormone · PACAPR1 · GPR · Latrophilin (1, 2, 3, ELTD1) · Methuselah-like proteins · Parathyroid hormone (1, 2) · Secretin · Vasoactive intestinal peptide (1, 2)

Class C: Metabotropic
glutamate / pheromone

Taste	TAS1R (1, 2, 3) · TAS2R (1, 3, 4, 5, 8, 9, 10, 12, 13, 14, 16, 19, 20, 30, 31, 38, 39, 40, 41, 42, 43, 45, 46, 50)
Other	Calcium-sensing receptor · GABA B (1, 2) · Glutamate receptor (Metabotropic glutamate (1, 2, 3, 4, 5, 6, 7, 8)) · GPRC6A · GPR (156, 158, 179) · RAIG (1, 2, 3, 4)

Class F:
Frizzled / Smoothened

Frizzled	Frizzled (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
Smoothened	Smoothened

B trdu: iter (nrpl/grfl/cytl/horl), csrc (lgic, enzr, gprc, igsr, intg, nrpr/grfr/cytr), itra (adap, gbpr, mapk), calc, lipd; path (hedp, wntp, tgfp+mapp, notp, jakp, fsap, hipp, tlrp)