Rhodopsin-like receptors are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s that comprise the largest group of

G protein-coupled receptor 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 evolutionarily related ...

Scope

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine, and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. GPCRs are usually described as "superfamily" because they embrace a group of

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence. The currently known superfamily members include the rhodopsin-like GPCRs (this family), the secretin-like GPCRs, the cAMP receptors, the

fungal mating pheromone receptors Fungal pheromone mating factor receptors form a distinct family of G-protein-coupled receptors G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpenti ...

, and the

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

family. There is a specialised database for GPCRs.

Function

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neuropeptide, neurotransmitter, and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices.

Classes

Rhodopsin-like GPCRs have been classified into the following 19 subgroups (A1-A19) based on a phylogenetic analysis.

Subfamily A1

Chemokine receptor Chemokine receptors are cytokine receptors found on the surface of certain cells that interact with a type of cytokine called a chemokine. There have been 20 distinct chemokine receptors discovered in humans. Each has a rhodopsin-like 7-tran ...

** Chemokine (C-C motif) receptor 1 (, CKR1) ** Chemokine (C-C motif) receptor 2 (, CKR2) ** Chemokine (C-C motif) receptor 3 (, CKR3) ** Chemokine (C-C motif) receptor 4 (, CKR4) ** Chemokine (C-C motif) receptor 5 (, CKR5) ** Chemokine (C-C motif) receptor 8 (, CKR8) ** Chemokine (C-C motif) receptor-like 2 (, CKRX) * chemokine (C motif) receptor 1 (, CXC1) * chemokine (C-X3-C motif) receptor 1 (, C3X1) * GPR137B (, TM7SF1)

Subfamily A2

** Chemokine (C-C motif) receptor-like 1 (, CCR11) ** Chemokine (C-C motif) receptor 6 (, CKR6) ** Chemokine (C-C motif) receptor 7 (, CKR7) ** Chemokine (C-C motif) receptor 9 (, CKR9) ** Chemokine (C-C motif) receptor 10 (, CKRA) *

CXC chemokine receptors CXC chemokine receptors are integral membrane proteins that specifically bind and respond to cytokines of the CXC chemokine family. They represent one subfamily of chemokine receptors, a large family of G protein-linked receptors that are ...

** Chemokine (C-X-C motif) receptor 3 () ** Chemokine (C-X-C motif) receptor 4 (, Fusin) ** Chemokine (C-X-C motif) receptor 5 () ** Chemokine (C-X-C motif) receptor 6 (, BONZO) ** Chemokine (C-X-C motif) receptor 7 (, RDC1) *

Interleukin-8 Interleukin 8 (IL-8 or chemokine (C-X-C motif) ligand 8, CXCL8) is a chemokine produced by macrophages and other cell types such as epithelial cells, airway smooth muscle cells and endothelial cells. Endothelial cells store IL-8 in their storage ...

(IL8R) ** IL8R-α (, CXCR1) ** IL8R-β (, CXCR2) * Adrenomedullin receptor () * Duffy blood group, chemokine receptor (, DUFF) * G Protein-coupled Receptor 30 (, CML2, GPCR estrogen receptor)

Subfamily A3

Angiotensin II receptor The angiotensin II receptors, (ATR1) and (ATR2), are a class of G protein-coupled receptors with angiotensin II as their ligands. They are important in the renin–angiotensin system: they are responsible for the signal transduction of the vaso ...

** Angiotensin II receptor, type 1 (, AG2S) ** Angiotensin II receptor, type 2 (, AG22) **

Apelin receptor The Apelin Receptor (APLNR, also known as APJ) is a G protein-coupled receptor. APLNR possesses two endogenous ligands which are APELIN and ELABELA ELABELA (ELA, Apela, Toddler) is a hormonal peptide that in humans is encoded by the ''APELA'' ...

(, APJ) *

Bradykinin receptor The bradykinin receptor family is a group of G-protein coupled receptors whose principal ligand is the protein bradykinin. There are two Bradykinin receptors: the B1 receptor and the B2 receptor. B1 receptor Bradykinin receptor B1 (B1) is ...

Bradykinin receptor B1 Bradykinin receptor B1 (B1) is a G-protein coupled receptor encoded by the BDKRB1 gene in humans. Its principal ligand is bradykinin, a 9 amino acid peptide generated in pathophysiologic conditions such as inflammation, trauma, burns, shock, and a ...

(, BRB1) **

Bradykinin receptor B2 Bradykinin receptor B2 is a G-protein coupled receptor for bradykinin, encoded by the BDKRB2 gene in humans. Mechanism The B2 receptor (B2R) is a G protein-coupled receptor, probably coupled to Gq and Gi. A 2022 ''Nature'' cryo-EM study of h ...

(, BRB2) * GPR15 (, GPRF) * GPR25 ()

Subfamily A4

Opioid receptor Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostati ...

delta Opioid receptor Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

(, OPRD) **

kappa Opioid receptor Kappa (; uppercase Κ, lowercase κ or cursive ; , ''káppa'') is the tenth letter of the Greek alphabet, representing the voiceless velar plosive sound in Ancient and Modern Greek. In the system of Greek numerals, has a value of 20. It was d ...

(, OPRK) ** mu Opioid receptor (, OPRM) **

Nociceptin receptor The nociceptin opioid peptide receptor (NOP), also known as the nociceptin/orphanin FQ (N/OFQ) receptor or kappa-type 3 opioid receptor, is a protein that in humans is encoded by the ''OPRL1'' (opioid receptor-like 1) gene. The nociceptin recepto ...

(, OPRX) *

Somatostatin receptor Somatostatin receptors are receptors for the ligand somatostatin, a small neuropeptide associated with neural signaling, particularly in the post-synaptic response to NMDA receptor co-stimulation/activation. Somatostatin is encoded by a CRE ...

** Somatostatin receptor 1 (, SSR1) ** Somatostatin receptor 2 (, SSR2) ** Somatostatin receptor 3 (, SSR3) ** Somatostatin receptor 4 (, SSR4) **

Somatostatin receptor 5 Somatostatin receptor type 5 is a protein that in humans is encoded by the ''SSTR5'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA tha ...

(, SSR5) * GPCR neuropeptide receptor ** Neuropeptides B/W receptor 1 (, GPR7) ** Neuropeptides B/W receptor 2 (, GPR8) * GPR1 orphan receptor ()

Subfamily A5

Galanin receptor The galanin receptor is a G protein-coupled receptor, or metabotropic receptor which binds galanin. Galanin receptors can be found throughout the peripheral and central nervous systems and the endocrine system. So far three subtypes are known ...

** Galanin receptor 1 (, GALR) ** Galanin receptor 2 (, GALS) ** Galanin receptor 3 (, GALT) * Cysteinyl leukotriene receptor **

Cysteinyl leukotriene receptor 1 Cysteinyl leukotriene receptor 1, also termed CYSLTR1, is a receptor for cysteinyl leukotrienes (LT) (see cysteinyl leukotrienes). CYSLTR1, by binding these cysteinyl LTs (CysLTs; viz, LTC4, LTD4, and to a much lesser extent, LTE4) contributes ...

() **

Cysteinyl leukotriene receptor 2 Cysteinyl leukotriene receptor 2, also termed CYSLTR2, is a receptor for cysteinyl leukotrienes (LT) (see leukotrienes#Cysteinyl leukotrienes). CYSLTR2, by binding these cysteinyl LTs (CysLTs; viz, LTC4, LTD4, and to a much lesser extent, LTE4 ...

() *

Leukotriene B4 receptor The leukotriene B4 receptors (BLTRs) include the following two receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (bio ...

(, P2Y7) **

Leukotriene B4 receptor 2 Leukotriene B4 receptor 2, also known as BLT2, BLT2 receptor, and BLTR2, is an Integral membrane protein that is encoded by the LTB4R2 gene in humans and the Ltbr2 gene in mice. Discovered several years after the leukotriene B4 receptor 1 (BLT ...

() *

Relaxin receptor The relaxin receptors are a subclass of four closely related G protein-coupled receptors (GPCR) that bind relaxin peptide hormones. Below is list of human relaxin receptors, their endogenous peptide hormones, and what downstream enzymes are a ...

** Relaxin/insulin-like family peptide receptor 1 (, LGR7) ** Relaxin/insulin-like family peptide receptor 2 (, GPR106) ** Relaxin/insulin-like family peptide receptor 3 (, SALPR) ** Relaxin/insulin-like family peptide receptor 4 (, GPR100/GPR142) *

KiSS1-derived peptide receptor The KiSS1-derived peptide receptor (also known as GPR54 or the Kisspeptin receptor) is a G protein-coupled receptor which binds the peptide hormone kisspeptin (metastin). Kisspeptin is encoded by the metastasis suppressor gene KISS1, which is e ...

(GPR54) () *

Melanin-concentrating hormone receptor 1 Melanin-concentrating hormone receptor 1, also known as MCH1, is one of the melanin-concentrating hormone receptors found in all mammals. The protein encoded by this gene, a member of the G protein-coupled receptor family 1, is an integral plasma ...

(, GPRO) * Urotensin-II receptor (, UR2R)

Subfamily A6

Cholecystokinin receptor Cholecystokinin receptors or CCK receptors are a group of G-protein coupled receptors which bind the peptide hormones cholecystokinin (CCK) and gastrin. There are two different subtypes CCKA and CCKB which are ~50% homologous: Various chole ...

Cholecystokinin A receptor The Cholecystokinin A receptor is a human protein, also known as CCKAR or CCK1, with CCK1 now being the IUPHAR-recommended name. Function This gene encodes a G-protein coupled receptor that binds sulfated members of the cholecystokinin (CCK) ...

(, CCKR) **

Cholecystokinin B receptor The cholecystokinin B receptor also known as CCKBR or CCK2 is a protein that in humans is encoded by the ''CCKBR'' gene. This gene encodes a G protein-coupled receptor for gastrin and cholecystokinin (CCK), regulatory peptides of the brain and g ...

(, GASR) * Neuropeptide FF receptor ** Neuropeptide FF receptor 1 (, FF1R) ** Neuropeptide FF receptor 2 (, FF2R) *

Orexin receptor The orexin receptor (also referred to as the hypocretin receptor) is a G-protein-coupled receptor that binds the neuropeptide orexin. There are two variants, OX1 and OX2, each encoded by a different gene (, ). Both orexin receptors exhibit ...

Hypocretin (orexin) receptor 1 Orexin receptor type 1 (Ox1R or OX1), also known as hypocretin receptor type 1 (HcrtR1), is a protein that in humans is encoded by the HCRTR1 gene. Function The orexin 1 receptor (OX1), is a G-protein coupled receptor that is heavily expresse ...

(, OX1R) **

Hypocretin (orexin) receptor 2 Orexin receptor type 2 (Ox2R or OX2), also known as hypocretin receptor type 2 (HcrtR2), is a protein that in humans is encoded by the HCRTR2 gene. It should not be confused for the protein CD200R1 which shares the alias OX2R but is a distinct ...

(, OX2R) *

Vasopressin receptor The actions of vasopressin are mediated by stimulation of tissue-specific G protein-coupled receptors (GPCRs) called vasopressin receptors that are classified into the V1 (V1A), V2, and V3 (V1B) receptor subtypes. These three subtypes differ ...

Arginine vasopressin receptor 1A Vasopressin receptor 1A (V1AR), or arginine vasopressin receptor 1A (officially called AVPR1A) is one of the three major Receptor (biochemistry), receptor types for vasopressin (Arginine vasopressin receptor 1B, AVPR1B and Arginine vasopressin rec ...

(, V1AR) **

Arginine vasopressin receptor 1B Vasopressin V1b receptor (V1BR) also known as vasopressin 3 receptor (VPR3) or antidiuretic hormone receptor 1B is a protein that in humans is encoded by the ''AVPR1B'' (arginine vasopressin receptor 1B) gene. V1BR acts as a receptor for vasopres ...

(, V1BR) **

Arginine vasopressin receptor 2 Vasopressin receptor 2 (V2R), or arginine vasopressin receptor 2 (officially called AVPR2), is a protein that acts as receptor for vasopressin. AVPR2 belongs to the subfamily of G-protein-coupled receptors. Its activity is mediated by the Gs t ...

(, V2R) **

Oxytocin receptor The oxytocin receptor, also known as OXTR, is a protein which functions as receptor for the hormone and neurotransmitter oxytocin. In humans, the oxytocin receptor is encoded by the ''OXTR'' gene which has been localized to human chromosome 3p25 ...

() * Gonadotropin releasing hormone receptor (, GRHR) * Pyroglutamylated RFamide peptide receptor (, GPR103) * GPR22 (, GPRM) * GPR176 (, GPR)

Subfamily A7

* Bombesin receptor ** Bombesin-like receptor 3 () **

Neuromedin B receptor The neuromedin B receptor (NMBR), now known as BB1 is a G protein-coupled receptor whose endogenous ligand is neuromedin B. In humans, this protein is encoded by the ''NMBR'' gene. Neuromedin B receptor binds neuromedin B, a potent mitogen an ...

() ** Gastrin-releasing peptide receptor () *

Endothelin receptor There are at least four known endothelin receptors, ETA, ETB1, ETB2 and ETC, all of which are G protein-coupled receptors whose activation result in elevation of intracellular-free calcium, which constricts the smooth muscles of the blood vessels ...

Endothelin receptor type A Endothelin receptor type A, also known as ETA, is a human G protein-coupled receptor. Interactions Endothelin receptor type A has been shown to interact with HDAC7A and HTATIP. See also * Endothelin receptor There are at least four kno ...

(, ET1R) **

Endothelin receptor type B Endothelin receptor type B, (ET-B) is a protein that in humans is encoded by the ''EDNRB'' gene. Function Endothelin receptor type B is a G protein-coupled receptor which activates a phosphatidylinositol-calcium second messenger system. Its l ...

(, ETBR) **

GPR37 Probable G-protein coupled receptor 37 is a protein that in humans is encoded by the ''GPR37'' gene. GPR37 is primarily found in the central nervous system (CNS), with significant expression observed in various CNS regions including the amygdala, ...

(, ETBR-LP2) * Neuromedin U receptor ** Neuromedin U receptor 1 () ** Neuromedin U receptor 2 () *

Neurotensin receptor Neurotensin receptors are transmembrane receptors that bind the neurotransmitter neurotensin. Two of the receptors encoded by the and genes contain seven transmembrane helices and are G protein coupled. Numerous crystal structures have been ...

Neurotensin receptor 1 Neurotensin receptor type 1 is a protein that in humans is encoded by the ''NTSR1'' gene. The neurotensin receptor is primarily responsible for mediating the effects of the neuropeptide neurotensin. Structure Neurotensin receptor type 1 (NTS ...

(, NTR1) ** Neurotensin receptor 2 (, NTR2) * Thyrotropin-releasing hormone receptor (, TRFR) *

Growth hormone secretagogue receptor Growth hormone secretagogue receptor(GHS-R), also known as ghrelin receptor, is a G protein-coupled receptor that binds growth hormone secretagogues (GHSs), such as ghrelin, the "hunger hormone". The role of GHS-R is thought to be in regulating en ...

() *

GPR39 G-protein coupled receptor 39 is a protein that in humans is encoded by the ''GPR39'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA th ...

() *

Motilin receptor Motilin receptor is a G protein-coupled receptor (previously GPCR38) that binds motilin. It was first cloned in 1999 by Merck Laboratories. and scientists have since been searching for compounds to modify its behavior. The Protein primary struct ...

(, GPR38)

Subfamily A8

Anaphylatoxin receptors The anaphylatoxin receptors are a group of G-protein coupled receptors which bind anaphylatoxin Anaphylatoxins, or complement peptides, are fragments ( C3a, C4a and C5a) that are produced as part of the activation of the complement system. Comp ...

C3a receptor The C3a receptor also known as complement component 3a receptor 1 (C3AR1) is a G protein-coupled receptor protein involved in the complement system. The receptor binds to complement component C3a, although there is limited evidence that this r ...

(, C3AR) **

C5a receptor The C5a receptor also known as complement component 5a receptor 1 (C5AR1) or CD88 (Cluster of Differentiation 88) is a G protein-coupled receptor for C5a. It functions as a complement receptor. C5a receptor 1 modulates inflammatory responses, ...

(, C5AR) ** Chemokine-like receptor 1 (, CML1) * Formyl peptide receptor **

Formyl peptide receptor 1 Formyl peptide receptor 1 (FPR1, FPR1 receptor, fMet-Leu-Phe receptor 1, FMLP receptor 1, or N-formylmethionyl-leucyl-phenylalanine receptor 1) is a cell surface receptor protein that in humans is encoded by the ''formyl peptide receptor 1'' ('' ...

(, FMLR) ** Formyl peptide receptor-like 1 (, FML2) ** Formyl peptide receptor-like 2 (, FML1) *

MAS1 oncogene The MAS1 oncogene (MAS receptor) is a G protein-coupled receptor which binds the angiotensin II metabolite angiotensin (1-7). The MAS1 receptor, when activated by binding angiotensin-(1-7), opposes many of the effects of the angiotensin II rece ...

** MAS1 (, MAS) ** MAS1L (, MRG) * GPR1 () *

GPR32 G protein-coupled receptor 32, also known as GPR32 or the RvD1 receptor, is a human receptor (biochemistry) belonging to the rhodopsin-like subfamily of G protein-coupled receptors. Gene The ''GPR32'' was initially identified and defined by mo ...

(, GPRW) * GPR44 () * GPR77 (, C5L2)

Subfamily A9

Melatonin receptor Melatonin receptors are G protein-coupled receptors (GPCR) which bind melatonin. Three types of melatonin receptors have been cloned. The MT1 (or Mel1A or MTNR1A) and MT2 (or Mel1B or MTNR1B) receptor subtypes are present in humans and other ...

Melatonin receptor 1A Melatonin receptor type 1A is a protein that in humans is encoded by the ''MTNR1A'' gene. Function This gene encodes the MT1 protein, one of two high-affinity forms of a receptor for melatonin, the primary hormone secreted by the pineal gland. ...

(, ML1A) **

Melatonin receptor 1B Melatonin receptor 1B, also known as MTNR1B, is a protein that in humans is encoded by the ''MTNR1B'' gene. Function This gene encodes the MT2 protein, one of two high-affinity forms of a receptor for melatonin, the primary hormone secreted by ...

(, ML1B) * Neurokinin receptor **

Tachykinin receptor 1 The tachykinin receptor 1 (TACR1) also known as neurokinin 1 receptor (NK1R) or substance P receptor (SPR) is a G protein coupled receptor found in the central nervous system and peripheral nervous system. The endogenous ligand for this receptor ...

(, NK1R) **

Tachykinin receptor 2 Substance-K receptor is a protein that in humans is encoded by the ''TACR2'' gene. Function This gene belongs to a family of genes that function as receptors for tachykinins. Receptor affinities are specified by variations in the 5'-end of th ...

(, NK2R) ** Tachykinin receptor 3 (, NK3R) * Neuropeptide Y receptor ** Neuropeptide Y receptor Y1 (, NY1R) ** Neuropeptide Y receptor Y2 (, NY2R) **

Pancreatic polypeptide receptor 1 Pancreatic polypeptide receptor 1, also known as Neuropeptide Y receptor type 4, is a protein that in humans is encoded by the ''PPYR1'' gene. Selective Ligands Agonists * Pancreatic polypeptide * Neuropeptide Y (endogenous agonist, non subtype ...

(, NY4R) ** Neuropeptide Y receptor Y5 (, NY5R) * Prolactin-releasing peptide receptor ( PRLHR, GPRA) * Prokineticin receptor 1 (, GPR73) * Prokineticin receptor 2 (, PKR2) * GPR19 (, GPRJ) * GPR50 (, ML1X) *

GPR75 Probable G-protein coupled receptor 75 is a protein that in humans is encoded by the ''GPR75'' gene. Function GPR75 is a member of the G protein-coupled receptor family. GPRs are cell surface receptors that activate guanine-nucleotide binding ...

() * GPR83 (, GPR72)

Subfamily A10

* Glycoprotein hormone receptor ** FSH-receptor () **

Luteinizing hormone/choriogonadotropin receptor The luteinizing hormone/choriogonadotropin receptor (LHCGR), also lutropin/choriogonadotropin receptor (LCGR) or luteinizing hormone receptor (LHR), is a transmembrane receptor found predominantly in the ovary and testis, but also many extragona ...

(, LSHR) ** Thyrotropin receptor () * Leucine-rich repeat-containing G protein-coupled receptor 4 (, GPR48) * Leucine-rich repeat-containing G protein-coupled receptor 5 (, GPR49) * Leucine-rich repeat-containing G protein-coupled receptor 6 ()

Subfamily A11

* GPR40-related receptor **

Free fatty acid receptor 1 Free fatty acid receptor 1 (FFAR1), also known as G-protein coupled receptor 40 (GPR40), is a rhodopsin-like G-protein coupled receptor that is coded (i.e., its synthesis is directed) by the ''FFAR1'' gene. This gene is located on the short (i.e. ...

(, GPR40) **

Free fatty acid receptor 2 Free fatty acid receptor 2 (FFAR2), also known as G-protein coupled receptor 43 (GPR43), is a rhodopsin-like G-protein coupled receptor (GPCR) encoded by the ''FFAR2'' gene. In humans, the ''FFAR2'' gene is located on the long arm of chromosome ...

(, GPR43) **

Free fatty acid receptor 3 Free fatty acid receptor 3 (FFAR3, also termed GPR41) protein is a G protein coupled receptor (i.e., GPR or GPCR) that in humans is encoded by the ''FFAR3'' gene (i.e., ''GPR41'' gene). GPRs reside on cell surfaces, bind specific signaling molecu ...

(, GPR41) ** GPR42 (, FFAR1L) * P2 purinoceptor ** Purinergic receptor P2Y₁ () ** Purinergic receptor P2Y₂ () ** Purinergic receptor P2Y₄ () ** Purinergic receptor P2Y₆ () ** Purinergic receptor P2Y₈ () ** Purinergic receptor P2Y₁₁ () *

Hydroxycarboxylic acid receptor 1 Hydroxycarboxylic acid receptor 1 (HCA1), formerly known as G protein-coupled receptor 81 (GPR81), is a protein that in humans is encoded by the ''HCAR1'' gene. HCA1, like the other hydroxycarboxylic acid receptors HCA2 and HCA3, is a G protei ...

(, GPR81) * Hydroxycarboxylic acid receptor 2, Niacin receptor 1 (, GPR109A) * Hydroxycarboxylic acid receptor 3, Niacin receptor 2 (, GPR109B, HM74) * GPR31 (, GPRV) * GPR82 () * Oxoglutarate (alpha-ketoglutarate) receptor 1 (, GPR80) * Succinate receptor 1 (, GPR91)

Subfamily A12

* P2 purinoceptor ** Purinergic receptor P2Y₁₂ () ** Purinergic receptor P2Y₁₃ (, GPR86) ** Purinergic receptor P2Y₁₄ (, UDP-glucose receptor, KI01) * GPR34 () * GPR87 () * GPR171 (, H963) * Platelet-activating factor receptor (, PAFR)

Subfamily A13

Cannabinoid receptor Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system of vertebrates a class of cell membrane receptors in the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cann ...

** Cannabinoid receptor 1 (brain) (, CB1R) **

Cannabinoid receptor 2 (macrophage) The cannabinoid receptor 2 (CB2), is a G protein-coupled receptor from the cannabinoid receptor family that in humans is encoded by the ''CNR2'' gene. It is closely related to the cannabinoid receptor 1 (CB1), which is largely responsible for t ...

(, CB2R) * Lysophosphatidic acid receptor ** Lysophosphatidic acid receptor 1 () ** Lysophosphatidic acid receptor 2 () ** Lysophosphatidic acid receptor 3 () * Sphingosine 1-phosphate receptor ** Sphingosine 1-phosphate receptor 1 () ** Sphingosine 1-phosphate receptor 2 () ** Sphingosine 1-phosphate receptor 3 () ** Sphingosine 1-phosphate receptor 4 () ** Sphingosine 1-phosphate receptor 5 () * Melanocortin/ACTH receptor **

Melanocortin 1 receptor The melanocortin 1 receptor (MC1R), also known as melanocyte-stimulating hormone receptor (MSHR), melanin-activating peptide receptor, or melanotropin receptor, is a G protein–coupled receptor that binds to a class of pituitary peptide hormon ...

(, MSHR) **

Melanocortin 3 receptor Melanocortin 3 receptor (MC3R) is a protein that in humans is encoded by the gene. Function This gene encodes MC3R, a G-protein coupled receptor (GPCR) for melanocyte-stimulating hormone (MSH) and adrenocorticotropic hormone (ACTH) that is exp ...

() **

Melanocortin 4 receptor The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor involved in regulating energy homeostasis, appetite, and sexual function. It plays a key role in metabolic processes and is predisposes to certain forms of obesity in humans. MC4R ...

() **

Melanocortin 5 receptor Melanocortin 5 receptor (MC5R) is a protein that in humans is encoded by the gene. It is located on the chromosome 18 in the human genome. When the MC5R was disrupted in transgenic mice, it induced disruption of their exocrine glands and resulte ...

() **

ACTH receptor Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a Adrenocorticotropic hormone (medication), medication and ...

(), ACTR) *

GPR3 G-protein coupled receptor 3 is a protein that in humans is encoded by the ''GPR3'' gene. The protein encoded by this gene is a member of the G protein-coupled receptor family of transmembrane receptors and is involved in signal transduction. GPR ...

() *

GPR6 G protein-coupled receptor 6, also known as GPR6, is a protein which in humans is encoded by the ''GPR6'' gene. Function GPR6 is a member of the G protein-coupled receptor family of transmembrane receptors. It has been reported that GPR6 is b ...

() *

GPR12 Probable G-protein coupled receptor 12 is a protein that in humans is encoded by the ''GPR12'' gene. The gene product of GPR12 is an orphan receptor, meaning that its endogenous ligand is currently unknown. Gene disruption of GPR12 in mice resul ...

(, GPRC)

Subfamily A14

Eicosanoid receptor Most of the eicosanoid receptors are integral membrane protein G protein-coupled receptors (GPCRs) that receptor (biochemistry), bind and respond to eicosanoid signaling molecules. Eicosanoids are rapidly metabolized to inactive products and theref ...

** Prostaglandin D₂ receptor (, PD2R) ** Prostaglandin E₁ receptor (, PE21) ** Prostaglandin E₂ receptor (, PE22) ** Prostaglandin E₃ receptor (, PE23) ** Prostaglandin E₄ receptor (, PE24) **

Prostaglandin F receptor Prostaglandin F receptor (FP) is a receptor belonging to the prostaglandin (PG) group of receptors. FP binds to and mediates the biological actions of prostaglandin F2α (PGF2α). It is encoded in humans by the ''PTGFR'' gene. Gene The ''PT ...

(, PF2R) ** Prostaglandin I₂ (prostacyclin) receptor (, PI2R) ** Thromboxane A₂ receptor (, TA2R)

Subfamily A15

* Lysophosphatidic acid receptor ** Lysophosphatidic acid receptor 4 () ** Lysophosphatidic acid receptor 5 () ** Lysophosphatidic acid receptor 6 () * P2 purinoceptor ** Purinergic receptor P2Y₁₀ (, P2Y10) *

Protease-activated receptor Protease-activated receptors (PAR) are a subfamily of related G protein-coupled receptors that are activated by cleavage of part of their extracellular domain. They are highly expressed in platelets, and also on endothelial cells, fibroblasts ...

** Coagulation factor II (thrombin) receptor-like 1 (, PAR2) ** Coagulation factor II (thrombin) receptor-like 2 (, PAR3) ** Coagulation factor II (thrombin) receptor-like 3 (, PAR4) * Epstein-Barr virus induced gene 2 (lymphocyte-specific G protein-coupled receptor) () *

Proton-sensing G protein-coupled receptors Proton-sensing G protein-coupled receptors are transmembrane receptors which sense acidic pH and include GPR132 (G2A), GPR4, GPR68 (OGR1) and GPR65 (TDAG8). These G protein-coupled receptors are activated when extracellular pH falls into the ...

GPR4 G-protein coupled receptor 4 is a protein that in humans is encoded by the ''GPR4'' gene. See also *Proton-sensing G protein-coupled receptors Proton-sensing G protein-coupled receptors are transmembrane receptors which sense acidic pH and in ...

() ** GPR65 () ** GPR68 () ** GPR132 (, G2A) *

GPR17 Uracil nucleotide/cysteinyl leukotriene receptor is a G protein-coupled receptor that in humans is encoded by the ''GPR17'' gene located on chromosome 2 at position q21. The actual activating ligands for and some functions of this receptor are dis ...

(, GPRH) *

GPR18 ''N''-Arachidonyl glycine receptor (NAGly receptor), also known as G protein-coupled receptor 18 (GPR18), is a protein that in humans is encoded by the ''GPR18'' gene. Along with the other previously orphan receptors GPR55 and GPR119, GPR18 has b ...

(, GPRI) * GPR20 (, GPRK) *

GPR35 G protein-coupled receptor 35 also known as GPR35 is a G protein-coupled receptor which in humans is encoded by the ''GPR35'' gene. Heightened expression of GPR35 is found in immune and gastrointestinal tissues, including the crypts of Lieberküh ...

() *

GPR55 G protein-coupled receptor 55 also known as GPR55 is a G protein-coupled receptor that in humans is encoded by the ''GPR55'' gene. GPR55, along with GPR119 and GPR18, have been implicated as novel cannabinoid receptors. History GPR55 was ide ...

() *

Coagulation factor II receptor Proteinase-activated receptor 1 (PAR1) also known as protease-activated receptor 1, coagulation factor II receptor and thrombin receptor is a protein that in humans is encoded by the ''F2R'' gene. PAR1 is a G protein-coupled receptor and one of ...

(, THRR)

Subfamily A16

Opsin Animal opsins are G-protein-coupled receptors and a group of proteins made light-sensitive via a chromophore, typically retinal. When bound to retinal, opsins become retinylidene proteins, but are usually still called opsins regardless. Most pro ...

s **

Rhodopsin Rhodopsin, also known as visual purple, is a protein encoded by the ''RHO'' gene and a G-protein-coupled receptor (GPCR). It is a light-sensitive receptor protein that triggers visual phototransduction in rod cells. Rhodopsin mediates dim ...

(, OPSD) ** Opsin 1 (cone pigments), short-wave-sensitive (color blindness, tritan) (, OPSB) (blue-sensitive opsin) ** Opsin 1 (cone pigments), medium-wave-sensitive (color blindness, deutan) (, OPSG) (green-sensitive opsin) ** Opsin 1 (cone pigments), long-wave-sensitive (color blindness, protan) (, OPSR) (red-sensitive opsin) ** Opsin 3, Panopsin () ** Opsin 4, Melanopsin () ** Opsin 5 (, GPR136) ** Retinal G protein coupled receptor () ** Retinal pigment epithelium-derived rhodopsin homolog (, OPSX) (visual pigment-like receptor opsin)

Subfamily A17

* 5-Hydroxytryptamine (5-HT) receptor ** 5-HT_2A (, 5H2A) ** 5-HT_2B (, 5H2B) ** 5-HT_2C (, 5H2C) ** 5-HT₆ (, 5H6) *

Adrenergic receptor The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like b ...

** Alpha_1A (, A1AA) ** Alpha_1B (, A1AB) ** Alpha_1D (, A1AD) ** Alpha_2A (, A2AA) ** Alpha_2B (, A2AB) ** Alpha_2C (, A2AC) ** Beta₁ (, B1AR) ** Beta₂ (, B2AR) ** Beta₃ (, B3AR) *

Dopamine receptor Dopamine receptors are a class of G protein-coupled receptors that are prominent in the vertebrate central nervous system (CNS). Dopamine receptors activate different effectors through not only G-protein coupling, but also signaling through diff ...

** D₁ (, DADR) ** D₂ (, D2DR) ** D₃ (, D3DR) ** D₄ (, D4DR) ** D₅ (, DBDR) * Trace amine receptor **

TAAR1 Trace amine-associated receptor 1 (TAAR1) is a trace amine-associated receptor (TAAR) protein that in humans is encoded by the ''TAAR1'' gene. TAAR1 is a primarily intracellular amine-activated and G protein-coupled receptor (GPCR) that is p ...

(, TAR1) **

TAAR2 Trace amine-associated receptor 2 (TAAR2), formerly known as G protein-coupled receptor 58 (GPR58), is a protein that in humans is encoded by the ''TAAR2'' gene. TAAR2 is co-expressed with Gα proteins; however, its signal transduction mechani ...

(, GPR58) **

TAAR3 Putative trace amine-associated receptor 3 (TAAR3) is a human pseudogene with the gene symbol ''TAAR3P''. Retrieved 28 November 2019 In other species such as mice, TAAR3 is a functional protein-coding gene that encodes a trace amine-associated re ...

(, GPR57) **

TAAR5 Trace amine-associated receptor 5 is a protein that in humans is encoded by the ''TAAR5'' gene. In vertebrates, TAAR5 is expressed in the olfactory epithelium. Human TAAR5 (hTAAR5) is a functional trace amine-associated receptor which acts as a ...

(, PNR) **

TAAR6 Trace amine associated receptor 6, also known as TAAR6, is a protein which in humans is encoded by the ''TAAR6'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequen ...

(, TAR4) **

TAAR8 Trace amine-associated receptor 8 is a protein that in humans is encoded by the ''TAAR8'' gene. In humans, TAAR8 is the only trace amine-associated receptor that is known to be Gi/o-coupled. In humans, molecular modelling and docking experiments ...

(, GPR102) **

TAAR9 Trace amine-associated receptor 9 is a protein that in humans is encoded by the ''TAAR9'' gene. TAAR9 is a member of a large family of rhodopsin G protein–coupled receptors (GPCRs, or GPRs). GPCRs contain 7 transmembrane domains and transduce ...

(, TAR3) * Histamine H₂ receptor (, HH2R)

Subfamily A18

* Histamine H₁ receptor (, HH1R) * Histamine H₃ receptor () * Histamine H₄ receptor () *

Adenosine receptor The adenosine receptors (or P1 receptors) are a class of Purinergic receptor, purinergic G protein-coupled receptors with adenosine as the endogenous ligand (biochemistry), ligand. There are four known types of adenosine receptors in humans: Aden ...

** A₁ (, AA1R) ** A_2a (, AA2A) ** A_2b (, AA2B) ** A₃ (, AA3R) *

Muscarinic acetylcholine receptor Muscarinic acetylcholine receptors (mAChRs) are acetylcholine receptors that form G protein-coupled receptor, G protein-coupled receptor complexes in the cell membranes of certain neurons and other Cell (biology), cells. They play several role ...

** M₁ (, ACM1) ** M₂ (, ACM2) ** M₃ (, ACM3) ** M₄ (, ACM4) ** M₅ (, ACM5) * GPR21 (, GPRL) * GPR27 () * GPR45 (, PSP24) * GPR52 () * GPR61 () * GPR62 () * GPR63 () *

GPR78 Probable G-protein coupled receptor 78 is a protein that in humans is encoded by the ''GPR78'' gene. G protein-coupled receptors (GPCRs, or GPRs) contain 7 transmembrane domains and transduce extracellular signals through heterotrimeric G prote ...

() *

GPR84 Probable G-protein coupled receptor 84 is a protein that in humans is encoded by the ''GPR84'' gene. Discovery GPR84 (EX33) was described practically in the same time by two groups. One was the group of Timo Wittenberger in the Zentrum fur Mol ...

() * GPR85 () *

GPR88 Probable G-protein coupled receptor 88 is a protein that in humans is encoded by the ''GPR88'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides ...

() * GPR101 () * GPR161 (, RE2) * GPR173 (, SREB3)

Subfamily A19

* 5-Hydroxytryptamine (5-HT) receptor ** 5-HT_1A (, 5H1A) ** 5-HT_1B (, 5H1B) ** 5-HT_1D (, 5H1D) ** 5-HT_1E (, 5H1E) ** 5-HT_1F (, 5H1F) ** 5-HT₄ () ** 5-HT_5A (, 5H5A) ** 5-HT₇ (, 5H7)

Unclassified

Olfactory receptor Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give ...

* Nematode chemoreceptor (multiple, including ) *

Taste receptor A taste receptor or tastant is a type of cellular receptor that 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 ...

type 2 *

Vomeronasal receptor Vomeronasal receptors are a class of olfactory receptors that putatively function as receptor (biology), receptors for pheromones. Pheromones have evolved in all animal phyla, to signal sex and dominance status, and are responsible for stereotypi ...

type 1 **

VN1R1 Vomeronasal type-1 receptor 1 is a protein that in humans is encoded by the ''VN1R1'' gene. Function Pheromones are chemical signals that elicit specific behavioral responses and physiologic alterations in recipients of the same species. The p ...

VN1R2 Vomeronasal type-1 receptor 2 is a protein that in humans is encoded by the ''VN1R2'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA th ...

VN1R3 Vomeronasal type-1 receptor 3 is a protein that is encoded by the ''VN1R3'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is tran ...

** VN1R4 **

VN1R5 Vomeronasal type-1 receptor 5 is a protein that in humans is encoded by the ''VN1R5'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA th ...

References

External links

* * This database includes multiple sequence alignments of all GPCR families and sub-families. {{G protein-coupled receptors G protein-coupled receptors Protein domains Protein families