The class C G-protein-coupled receptors () are a class of

G-protein coupled receptors G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of protein family, evolution ...

that include the

metabotropic glutamate receptor The metabotropic glutamate receptors, or mGluRs, are a type of glutamate receptor that are active through an indirect metabotropic process. They are members of the group C family of G-protein-coupled receptors, or GPCRs. Like all glutamate rece ...

s () and several additional receptors. Structurally they are composed of four elements; an

N-terminal The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

signal sequence; a large hydrophilic extracellular agonist-binding region containing several conserved

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometime ...

residues which could be involved in

disulphide bonds In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

; a shorter region containing seven transmembrane domains; and a

C-terminal The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...

cytoplasmic domain of variable length. This

protein family A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be c ...

includes

s, the extracellular

calcium-sensing receptor The calcium-sensing receptor (CaSR) is a Class C G-protein coupled receptor which senses extracellular levels of calcium ions. It is primarily expressed in the parathyroid gland, the renal tubules of the kidney and the brain. In the parathyroid ...

s, 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 **

Calcium-sensing receptor The calcium-sensing receptor (CaSR) is a Class C G-protein coupled receptor which senses extracellular levels of calcium ions. It is primarily expressed in the parathyroid gland, the renal tubules of the kidney and the brain. In the parathyroid ...

() **

GPRC6A G protein-coupled receptor family C group 6 member A (GPRC6A) is a protein that in humans is encoded by the ''GPRC6A'' gene. This protein functions as a receptor of L-α-amino acids, cations (e.g., calcium), osteocalcin, and steroids. It is a mem ...

()

GABA_B receptors

* GABA_B receptor (gamma-aminobutyric acid) ** GABA_B receptor 1 () ** GABA_B receptor 2 ()

Metabotropic glutamate receptors

Metabotropic glutamate receptor The metabotropic glutamate receptors, or mGluRs, are a type of glutamate receptor that are active through an indirect metabotropic process. They are members of the group C family of G-protein-coupled receptors, or GPCRs. Like all glutamate rece ...

s (mGluR) ** mGluR₁ () ** mGluR₂ () ** mGluR₃ () ** mGluR₄ () ** mGluR₅ () ** mGluR₆ () ** mGluR₇ () ** mGluR₈ ()

RAIG

Retinoic acid-inducible orphan G protein-coupled receptor The Retinoic Acid-Inducible orphan G-protein-coupled receptors (RAIG) are a group of four closely related G protein-coupled receptors whose expression is induced by retinoic acid. The exact function of these proteins has not been determined bu ...

s (RAIG) ** RAIG₁ () ** RAIG₂ () ** RAIG₃ () ** RAIG₄ ()

Taste receptors

Taste receptor A taste receptor or tastant is a type of cellular receptor which facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locat ...

** Taste receptor, type 1, member 1 () ** Taste receptor, type 1, member 2 () ** Taste receptor, type 1, member 3 ()

Orphan

* Class C

Orphan receptor In biochemistry, an orphan receptor is a protein that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified. If a ligand for an orphan receptor is later discovered, the receptor is referred t ...

s **

GPR158 Probable G-protein coupled receptor 158 is a protein that in humans is encoded by the ''GPR158'' gene. Function This protein is an orphan class C GPCR. It is highly expressed in the brain, where it binds to RGS7, an inhibitor of Gi/o-coupled ...

() **

GPR179 Probable G-protein coupled receptor 179 is a protein that in humans is encoded by the ''GPR179'' gene. Clinical relevance Mutations in this gene have been associated to cases of congenital stationary Night Blindness. References Further read ...

() ** GPR156 ()

Other

* Bride of sevenless protein * Vomeronasal receptor, type 2

References

G protein-coupled receptors {{transmembranereceptor-stub