Class C GPCR

G-protein coupled receptor

7 transmembrane receptor (metabotropic glutamate family)

Identifiers

Symbol

7tm_3

Pfam

PF00003

InterPro

IPR000337

PROSITE

PDOC00754

TCDB

9.A.14

OPM superfamily

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

^ ^a ^b 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.

Cell surface receptor: G protein-coupled receptors

Class A: Rhodopsin-like

Neurotransmitter

Adrenergic	α1 (A B D) α2 (A B C) β1 β2 β3
Purinergic	Adenosine (A1 A2A A2B A3) P2Y (1 2 4 5 6 8 9 10 11 12 13 14)
Serotonin	(all but 5-HT3) 5-HT1 (A B D E F) 5-HT2 (A B C) 5-HT (4 5A 6 7)
Other	Acetylcholine (M1 M2 M3 M4 M5) Dopamine D1 D2 D3 D4 D5 GHB receptor Histamine H1 H2 H3 H4 Melatonin (1A 1B 1C) TAAR (1 2 5 6 8 9)

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) Hydroxycarboxylic acids 1 2 3 Lysophosphatidic acid (1 2 3 4 5 6) Lysophospholipid (1 2 3 4 5 6 7 8) 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 (1
2))
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)
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

Taste, bitter	TAS2R 1 3 4 5 7 8 9 10 13 14 16 19 20 30 31 38 39 40 41 42 43 45 46 50 60 Vomeronasal receptor type 1
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 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

Adhesion	ADGRB Brain-specific angiogenesis inhibitor 1 2 3 ADGRC Cadherin 1 2 3 ADGRE EMR 1 2 3 CD97 ADGRG 1 2 3 4 5 6 7 ADGRL Latrophilin 1 2 3 ELTD1
Orphan	GPR (56 64 97 98 110 111 112 113 114 115 116 123 124 125 126 128 133 143 144 155 157)
Other	Calcitonin CALCRL Corticotropin-releasing hormone (1 2) Glucagon (GR GIPR GLP1R GLP2R) Growth-hormone-releasing hormone PACAPR1 GPR Methuselah-like proteins Parathyroid hormone (1 2) Secretin Vasoactive intestinal peptide (1 2)

Class C: Metabotropic glutamate / pheromone

Taste, sweet	TAS1R 1 2 3 Vomeronasal receptor, type 2
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)