Rhodopsin-like receptors are a family

Protein family

A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....

 of protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s that comprise the largest group of G protein-coupled receptor

G protein-coupled receptor

G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...

s.

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

Protein family

A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....

 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 mating pheromone receptors

Fungal pheromone mating factor receptors form a distinct family of G-protein-coupled receptors.Mating factor receptors STE2 and STE3 are integral membrane proteins that may be involved in the response to mating factors on the cell membrane...

, and the metabotropic glutamate receptor

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...

 family. There is a specialised database for GPCRs

G protein-coupled receptors database

GPCRDB is a database of G protein-coupled receptors....

.

Function

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormones, neurotransmitters, 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 receptor
  Chemokine receptors are cytokine receptors found on the surface of certain cells, which interact with a type of cytokine called a chemokine. There have been 19 distinct chemokine receptors described in mammals...
  
   
  • Chemokine (C-C motif) receptor 1
    CCR1
    C-C chemokine receptor type 1 is a protein that in humans is encoded by the CCR1 gene.CCR1 has also recently been designated CD191 .-External links:...
    
     
  • Chemokine (C-C motif) receptor 2
    CCR2
    CCR2, short for chemokine receptor 2, is a chemokine receptor.CCR2 has also recently been designated CD192 .-External links:* at...
    
     
  • Chemokine (C-C motif) receptor 3
    CCR3 (gene)
    C-C chemokine receptor type 3 is a protein that in humans is encoded by the CCR3 gene.CCR3 has also recently been designated CD193 .-Interactions:CCR3 has been shown to interact with CCL5....
    
     
  • Chemokine (C-C motif) receptor 4
    CCR4
    C-C chemokine receptor type 4 is a protein that in humans is encoded by the CCR4 gene. CCR4 has also recently been designated CD194 .The protein encoded by this gene belongs to the G protein-coupled receptor family...
    
     
  • Chemokine (C-C motif) receptor 5
    CCR5
    C-C chemokine receptor type 5, also known as CCR5, is a protein that in humans is encoded by the CCR5 gene. CCR5 is a member of the beta chemokine receptors family of integral membrane proteins...
    
     
  • Chemokine (C-C motif) receptor 8 
  • Chemokine (C-C motif) receptor-like 2
    CCRL2
    C-C chemokine receptor-like 2 is a protein that in humans is encoded by the CCRL2 gene. Recently it was found that CCRL2 also acts as a receptor for the chemokine chemerin.- Function:...
    
     
• chemokine (C motif) receptor 1
  XCR1
  The "C" sub-family of chemokine receptors contains only one member: XCR1, the receptor for XCL1 and XCL2 .XCR1 is also known as GPR5.-External links:...
  
   
• chemokine (C-X3-C motif) receptor 1
  CX3CR1
  CX3C chemokine receptor 1 also known as the fractalkine receptor or G-protein coupled receptor 13 is a protein that in humans is encoded by the CX3CR1 gene...
  
   
• GPR137B
  GPR137B
  G protein-coupled receptor 137B also known as GPR137B is a G protein-coupled receptor which in humans is encoded by the GPR137B gene. The expression of GPR137B is upregulated during kidney development....
  
   

Subfamily A2

• Chemokine receptor
  Chemokine receptor
  Chemokine receptors are cytokine receptors found on the surface of certain cells, which interact with a type of cytokine called a chemokine. There have been 19 distinct chemokine receptors described in mammals...
  
   
  • Chemokine (C-C motif) receptor-like 1
    CCRL1
    C-C chemokine receptor type 11 is a protein that in humans is encoded by the CCRL1 gene.-Further reading:...
    
     
  • Chemokine (C-C motif) receptor 6
    C-C chemokine receptor type 6
    Chemokine receptor 6 also known as CCR6 is a CC chemokine receptor. protein which in humans is encoded by the CCR6 gene. CCR6 has also recently been designated CD196 .- Function :...
    
     
  • Chemokine (C-C motif) receptor 7 
  • Chemokine (C-C motif) receptor 9
    CCR9
    C-C chemokine receptor type 9 is a protein that in humans is encoded by the CCR9 gene.CCR9 has also recently been designated CDw199 .-Further reading:...
    
     
  • Chemokine (C-C motif) receptor 10
    CCR10
    C-C chemokine receptor type 10 is a protein that in humans is encoded by the CCR10 gene.-Further reading:...
    
     
• CXC chemokine receptors
  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 known as seven transmembrane proteins since they span the...
  
   
  • Chemokine (C-X-C motif) receptor 6
    CXCR6
    C-X-C chemokine receptor type 6 is a protein that in humans is encoded by the CXCR6 gene.CXCR6 has also recently been designated CD186 .-Further reading:...
    
     
  • Chemokine (C-X-C motif) receptor 7
    CXCR7
    C-X-C chemokine receptor type 7 is a protein that in humans is encoded by the CXCR7 gene.This gene encodes a member of the G-protein coupled receptor family. This protein was earlier thought to be a receptor for vasoactive intestinal peptide and was considered to be an orphan receptor...
    
     
• Interleukin-8  (IL8R)
  • IL8R-α 
  • IL8R-β 
• Adrenomedullin receptor 
• Duffy blood group, chemokine receptor
  Duffy antigen system
  Duffy antigen/chemokine receptor also known as Fy glycoprotein or CD234 is a protein that in humans is encoded by the DARC gene....
  
   
• G Protein-coupled Receptor 30
  GPR30
  G-protein coupled estrogen receptor 1 also known as the membrane estrogen receptor or G-protein coupled receptor 30 is a G protein-coupled receptor that in humans is encoded by the GPER gene...
  
   

Subfamily A3

• Angiotensin II receptor 
  • Angiotensin II receptor, type 1 
  • Angiotensin II receptor, type 2 
  • Apelin receptor
    Apelin receptor
    The apelin receptor is a G protein-coupled receptor which binds apelin....
    
     
• Bradykinin receptor
  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
    Bradykinin receptor B1
    Bradykinin receptor 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 allergy...
    
     
  • Bradykinin receptor B2
    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 is a G protein-coupled receptor, probably coupled to Gq and Gi. Gq stimulates phospholipase C to increase intracellular free calcium and Gi inhibits adenylate cyclase...
    
     
• GPR15
  GPR15
  G-protein coupled receptor 15 is a protein that in humans is encoded by the GPR15 gene.-Further reading:...
  
   
• GPR25
  GPR25
  Probable G-protein coupled receptor 25 is a protein that in humans is encoded by the GPR25 gene.-Further reading:...
  
   

Subfamily A4

• Opioid receptor
  Opioid receptor
  Opioid receptors are a group of 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 somatostatin receptors...
  
   
  • delta Opioid receptor
    Delta Opioid receptor
    The δ-opioid receptors, also known as delta opioid receptor or simply delta receptor, abbreviated DOR, is an opioid receptor that has enkephalins as its endogenous ligands.-Function:...
    
     
  • kappa Opioid receptor
    Kappa Opioid receptor
    The κ-opioid receptor is a protein that in humans is encoded by the OPRK1 gene. The κ-opioid receptor is one of five related receptors that bind opium-like compounds in the brain and are responsible for mediating the effects of these compounds...
    
     
  • mu Opioid receptor
    Mu Opioid receptor
    The μ-opioid receptors are a class of opioid receptors with high affinity for enkephalins and beta-endorphin but low affinity for dynorphins. They are also referred to as μ opioid peptide receptors. The prototypical μ receptor agonist is the opium alkaloid morphine; μ refers to morphine...
    
     
  • Nociceptin receptor
    Nociceptin receptor
    The nociceptin receptor or NOP also known as the orphanin FQ receptor or kappa-type 3 opioid receptor is a protein that in humans is encoded by the OPRL1 gene. The nociceptin receptor is a G protein-coupled receptor whose natural ligand is known as nociceptin or orphanin FQ, a 17 amino acid...
    
     
• Somatostatin receptor
  Somatostatin receptor
  There are five known somatostatin receptors:* SST1 * SST2 * SST3 * SST4 * SST5 All are G protein-coupled seven transmembrane receptors.-External links:...
  
   
  • Somatostatin receptor 1
    Somatostatin receptor 1
    Somatostatin receptor type 1 is a protein that in humans is encoded by the SSTR1 gene....
    
     
  • Somatostatin receptor 2
    Somatostatin receptor 2
    Somatostatin receptor type 2 is a protein that in humans is encoded by the SSTR2 gene.-Interactions:Somatostatin receptor 2 has been shown to interact with SHANK2....
    
     
  • Somatostatin receptor 3
    Somatostatin receptor 3
    Somatostatin receptor type 3 is a protein that in humans is encoded by the SSTR3 gene....
    
     
  • Somatostatin receptor 4
    Somatostatin receptor 4
    Somatostatin receptor type 4 is a protein that in humans is encoded by the SSTR4 gene.Somatostatin receptor type 4 is a protein that in humans is encoded by the SSTR4 gene....
    
     
  • Somatostatin receptor 5
    Somatostatin receptor 5
    Somatostatin receptor type 5 is a protein that in humans is encoded by the SSTR5 gene....
    
     
• GPCR neuropeptide receptor
  GPCR neuropeptide receptor
  GPCR neuropeptide receptors are G-protein coupled receptors which bind various neuropeptides. Members include:* Neuropeptide B/W receptor** NPBWR1** NPBWR2* Neuropeptide FF receptor** NPFFR1** NPFFR2* Neuropeptide S receptor** NPSR1...
  
   
  • Neuropeptides B/W receptor 1
    Neuropeptides B/W receptor 1
    Neuropeptides B/W receptor 1, also known as NPBW1, is a human protein encoded by the NPBWR1 gene.-Further reading:...
    
     
  • Neuropeptides B/W receptor 2
    Neuropeptides B/W receptor 2
    Neuropeptides B/W receptor 2, also known as NPBW2, is a human protein encoded by the NPBWR2 gene.-Further reading:...
    
     
• GPR1 orphan receptor
  GPR1
  G protein-coupled receptor 1, also known as GPR1, is a protein that in humans is encoded by the GPR1 gene.GPR1 is a member of the G protein-coupled receptor family of transmembrane receptors. It functions as a receptor for chemerin. Other receptors for chemerin include CMKLR1 and CCRL2.-Further...
  
   

Subfamily A5

• Galanin receptor
  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 to exist: GAL-R1, GAL-R2, and GAL-R3...
  
   
  • Galanin receptor 1
    Galanin receptor 1
    Galanin receptor 1 is a G-protein coupled receptor encoded by the GALR1 gene.-Further reading:...
    
     
  • Galanin receptor 2
    Galanin receptor 2
    Galanin receptor 2, is a G-protein coupled receptor encoded by the GALR2 gene.-Further reading:...
    
     
  • Galanin receptor 3
    Galanin receptor 3
    Galanin receptor 3 is a G-protein coupled receptor encoded by the GALR3 gene.-Further reading:...
    
     
• Cysteinyl leukotriene receptor
  • Cysteinyl leukotriene receptor 1
    Cysteinyl leukotriene receptor 1
    Cysteinyl leukotriene receptor 1 is a protein that in humans is encoded by the CYSLTR1 gene.-Further reading:...
    
     
  • Cysteinyl leukotriene receptor 2
    Cysteinyl leukotriene receptor 2
    Cysteinyl leukotriene receptor 2 is a protein that in humans is encoded by the CYSLTR2 gene.-Further reading:...
    
     
• Leukotriene B4 receptor
  Leukotriene B4 receptor
  Leukotriene B4 receptor 1 is a protein that in humans is encoded by the LTB4R gene....
  
   
  • Leukotriene B4 receptor
    Leukotriene B4 receptor
    Leukotriene B4 receptor 1 is a protein that in humans is encoded by the LTB4R gene....
    
     
  • Leukotriene B4 receptor 2
    Leukotriene B4 receptor 2
    Leukotriene B4 receptor 2 is a protein that in humans is encoded by the LTB4R2 gene.This is a low-affinity receptor for leukotrienes, especially leukotriene B4. It mediates chemotaxis of granulocytes and macrophages.-External links:*...
    
     
• Relaxin receptor
  Relaxin receptor
  The relaxin receptors are a subclass of four closely related G protein-coupled receptors that bind relaxin peptide hormones.Below is list of human relaxin receptors, their endogenous peptide hormones, and what down stream enzymes are activated or inhibited by the receptor....
  
   
  • Relaxin/insulin-like family peptide receptor 1
    Relaxin/insulin-like family peptide receptor 1
    Relaxin/insulin-like family peptide receptor 1, also known as RXFP1, is a human G protein coupled receptor.-Further reading:...
    
     
  • Relaxin/insulin-like family peptide receptor 2
    Relaxin/insulin-like family peptide receptor 2
    Relaxin/insulin-like family peptide receptor 2, also known as RXFP2, is a human G-protein coupled receptor.-Further reading:...
    
     
  • Relaxin/insulin-like family peptide receptor 3
    Relaxin/insulin-like family peptide receptor 3
    Relaxin/insulin-like family peptide receptor 3, also known as RXFP3, is a human G-protein coupled receptor.-Further reading:...
    
     
  • Relaxin/insulin-like family peptide receptor 4
    Relaxin/insulin-like family peptide receptor 4
    Relaxin/insulin-like family peptide receptor 4, also known as RXFP4, is a human G-protein coupled receptor.-Further reading:...
    
     
• KiSS1-derived peptide receptor
  KiSS1-derived peptide receptor
  The KiSS1-derived peptide receptor is a G protein-coupled receptor which binds the peptide hormone kisspeptin . Kisspeptin is encoded by the metastasis suppressor gene KISS1, which is expressed in a variety of endocrine and gonadal tissues...
  
   (GPR54)
• Melanin-concentrating hormone receptor 1
  Melanin-concentrating hormone receptor 1
  Melanin-concentrating hormone receptor 1, also known as MCH1, is one of the human melanin-concentrating hormone receptors.-Function:...
  
   
• Urotensin-II receptor
  Urotensin-II receptor
  The urotensin-II receptor is a G-protein coupled receptor which binds the peptide hormone urotensin-II....
  
   

Subfamily A6

• Cholecystokinin receptor
  Cholecystokinin receptor
  Cholecystokinin receptors or CCK receptors are a group of G-protein coupled receptors which bind the peptide hormones cholecystokinin or gastrin...
  
   
  • Cholecystokinin A receptor
    Cholecystokinin A receptor
    The extracellular, N-terminal, domain of this protein adopts a tertiary structure consisting of a few helical turns and a disulfide-cross linked loop...
    
     
  • Cholecystokinin B receptor
    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 , regulatory peptides of the brain and gastrointestinal tract...
    
     
• Neuropeptide FF receptor
  Neuropeptide FF receptor
  The neuropeptide FF receptors are members of the G-protein coupled receptor superfamily of integral membrane proteins which bind the pain modulatory neuropeptides AF and FF...
  
   
  • Neuropeptide FF receptor 1
    Neuropeptide FF receptor 1
    Neuropeptide FF receptor 1, also known as NPFF1 is a human protein, encoded by the NPFFR1 gene.-Further reading:...
    
     
  • Neuropeptide FF receptor 2
    Neuropeptide FF receptor 2
    Neuropeptide FF receptor 2, also known as NPFF2 is a human protein encoded by the NPFFR2 gene.-Further reading:...
    
     
• Orexin receptor
  Orexin receptor
  The orexin receptor is a G-protein-coupled receptor that binds the neuropeptide hormone orexin. There are two variants, OX1 and OX2, each encoded by a different gene .-External links:...
  
   
  • Hypocretin (orexin) receptor 1
    Hypocretin (orexin) receptor 1
    Orexin receptor type 1 , also known as hypocretin receptor type 1, is a protein that in humans is encoded by the HCRTR1 gene.- Function :...
    
     
  • Hypocretin (orexin) receptor 2
    Hypocretin (orexin) receptor 2
    Orexin receptor type 2 , also known as hypocretin receptor type 2, is a protein that in humans is encoded by the HCRTR2 gene.- Function :...
    
     
• Vasopressin receptor
  Vasopressin receptor
  A vasopressin receptor is a cell surface receptor which binds vasopressin. The three types of vasopressin receptor are members of the A6 subfamily of G-protein coupled receptors.-Subtypes:Humans express three subtypes: 1A, 1B and 2-Function:...
  
   
  • Arginine vasopressin receptor 1A
    Arginine vasopressin receptor 1A
    Arginine vasopressin receptor 1A is one of the three major receptor types for arginine vasopressin , and is present throughout the brain, as well as in the periphery in the liver, kidney, and vasculature.Arginine vasopressin receptor 1A is also known as:* V1a vasopressin receptor* antidiuretic...
    
     
  • Arginine vasopressin receptor 1B
    Arginine vasopressin receptor 1B
    Arginine vasopressin receptor 1B is a protein that acts as receptor for arginine vasopressin. AVPR1B belongs to the subfamily of G-protein coupled receptors...
    
     
  • Arginine vasopressin receptor 2
    Arginine vasopressin receptor 2
    Arginine vasopressin receptor 2 is a protein that acts as receptor for arginine vasopressin. AVPR2 belongs to the subfamily of G-protein-coupled receptors...
    
     
• Gonadotrophin releasing hormone receptor
  GNRHR
  Gonadotropin-releasing hormone receptor is a protein that in humans is encoded by the GNRHR gene.-Further reading:...
  
   
• GPR22
  GPR22
  Probable G-protein coupled receptor 22 is a protein that in humans is encoded by the GPR22 gene.-Further reading:...
  
   
• GPR103
  GPR103
  Pyroglutamylated RFamide peptide receptor also known as orexigenic neuropeptide QRFP receptor or G-protein coupled receptor 103 is a protein that in humans is encoded by the QRFPR gene.-Function:...
  
   
• GPR176
  GPR176
  Probable G-protein coupled receptor 176 is a protein that in humans is encoded by the GPR176 gene.-Further reading:...
  
   

Subfamily A7

• Bombesin receptor
  Bombesin receptor
  The bombesin receptors are a group of G-protein coupled receptors which bind bombesin.Three bombesin receptors are currently known:BB1, previously known as Neuromedin B receptor BB2, previously known as Gastrin-releasing peptide receptor...
  
   
  • Bombesin-like receptor 3
    Bombesin-like receptor 3
    The bombesin receptor subtype 3 also known as BRS-3 or BB3 is a protein which in humans is encoded by the BRS3 gene.- Function :...
    
     
  • Neuromedin B receptor
    Neuromedin B receptor
    The neuromedin B receptor , now known as BB1 is a G protein-coupled receptor whose endogenous ligand is neuromedin B ....
    
     
  • Gastrin-releasing peptide receptor
    Gastrin-releasing peptide receptor
    The gastrin-releasing peptide receptor , now properly known as BB2 is a G protein-coupled receptor whose endogenous ligand is gastrin releasing peptide...
    
     
• Endothelin receptor
  Endothelin receptor
  There are at least three known endothelin receptors, ETA, ETB1 and ETB2, all of which are G protein-coupled receptors whose activation result in elevation of intracellular-free calcium.-Clinical significance:...
  
   
  • Endothelin receptor type A
    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.-Further reading:...
    
     
  • Endothelin receptor type B
    Endothelin receptor type B
    Endothelin receptor type B, also known as ETB 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 ligand, endothelin, consists of a family of three...
    
     
  • GPR37
    GPR37
    Probable G-protein coupled receptor 37 is a protein that in humans is encoded by the GPR37 gene.-Interactions:GPR37 has been shown to interact with HSPA1A and Parkin .-Further reading:...
    
     
• Neuromedin U receptor
  Neuromedin U receptor
  The neuromedin U receptors are two G-protein coupled receptors which bind the neuropeptide hormones neuromedin U and neuromedin S. There are two subtypes of the neuromedin U receptor, each encoded by a separate gene .-Selective Ligands:...
  
   
  • Neuromedin U receptor 1
    Neuromedin U receptor 1
    Neuromedin-U receptor 1 is a protein that in humans is encoded by the NMUR1 gene.-Further reading:...
    
     
  • Neuromedin U receptor 2
    Neuromedin U receptor 2
    Neuromedin-U receptor 2 is a protein that in humans is encoded by the NMUR2 gene.-Further reading:...
    
     
• Neurotensin receptor
  Neurotensin receptor
  The 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...
  
   
  • Neurotensin receptor 1
    Neurotensin receptor 1
    Neurotensin receptor type 1 is a protein that in humans is encoded by the NTSR1 gene.-Further reading:...
    
     
  • Neurotensin receptor 2
    Neurotensin receptor 2
    Neurotensin receptor type 2 is a protein that in humans is encoded by the NTSR2 gene.-Further reading:...
    
     
• Thyrotropin-releasing hormone receptor
  Thyrotropin-releasing hormone receptor
  The thyrotropin-releasing hormone receptor is a G protein-coupled receptor which binds the tripeptide thyrotropin releasing hormone. The TRHR are found in the brain and when bound by TRH result act through phospholipase C to increase intracellular inositol trisphosphate....
  
   
• Growth hormone secretagogue receptor
  Growth hormone secretagogue receptor
  Growth hormone secretagogue receptor is a G protein-coupled receptor that binds ghrelin and plays a role in energy homeostasis and regulation of body weight.-Function:...
  
   
• GPR39
  GPR39
  G-protein coupled receptor 39 is a protein that in humans is encoded by the GPR39 gene.-Further reading:...
  
   
• Motilin receptor
  Motilin receptor
  Motilin receptor is a G protein-coupled receptor that binds motilin. Motilin in turn is an intestinal peptide that stimulates contraction of gut smooth muscle.-External links:...
  
   

Subfamily A8

• Anaphylatoxin receptors
  Anaphylatoxin receptors
  The anaphylatoxin receptors are a group of G-protein coupled receptors which bind anaphylatoxins. Members of this family include:* C3a receptor * C5a receptor * C5L2...
  
   
  • C3a receptor 
  • C5a receptor
    C5a receptor
    The C5a receptor also known as complement component 5a receptor 1 or CD88 is a G protein-coupled receptor for C5a...
    
     
  • Chemokine-like receptor 1
    CMKLR1
    Chemokine receptor-like 1 also known as ChemR23 is a protein that in humans is encoded by the CMKLR1 gene. Chemokine receptor-like 1 is a G protein-coupled receptor for the chemoattractant adipokine chemerin and the omega-3 fatty acid derived molecule resolvin E1...
    
     
• Formyl peptide receptor
  Formyl peptide receptor
  The formyl peptide receptors are a members of a class of G protein-coupled receptors involved in chemotaxis. These receptors where originally identified by their ability to bind N-formyl peptides such as N-formylmethionine produced by the degradation of either bacterial or host cells...
  
   
  • Formyl peptide receptor 1
    Formyl peptide receptor 1
    fMet-Leu-Phe receptor also known as the N-formyl peptide receptor is a protein that in humans is encoded by the FPR1 gene.-Further reading:...
    
     
  • Formyl peptide receptor-like 1
    Formyl peptide receptor-like 1
    N-formyl peptide receptor 2 is a protein that in humans is encoded by the FPR2 gene.-Further reading:...
    
     
  • Formyl peptide receptor-like 2
    Formyl peptide receptor-like 2
    N-formyl peptide receptor 3 is a protein that in humans is encoded by the FPR3 gene.-Further reading:...
    
     
• MAS1 oncogene
  MAS1 oncogene
  The MAS1 oncogene is a G protein-coupled receptor which binds the angiotensin-II metabolite angiotensin-. The MAS1 receptor when activated by binding angiotensin- opposes many of the effects of angiotensin-II activated angiotensin receptor...
  
   
  • MAS1
    MAS1
    MAS proto-oncogene is a protein that in humans is encoded by the MAS1 gene.-Further reading:...
    
     
  • MAS1L
    MAS1L
    Mas-related G-protein coupled receptor MRG is a protein that in humans is encoded by the MAS1L gene.-Further reading:...
    
     
• GPR1
  GPR1
  G protein-coupled receptor 1, also known as GPR1, is a protein that in humans is encoded by the GPR1 gene.GPR1 is a member of the G protein-coupled receptor family of transmembrane receptors. It functions as a receptor for chemerin. Other receptors for chemerin include CMKLR1 and CCRL2.-Further...
  
   
• GPR32
  GPR32
  G protein-coupled receptor 32, also known as GPR32, is a human gene belonging to the rhodopsin-like subfamily of G protein-coupled receptors. GPR32 is most closely related to the chemotaxic formyl peptide receptors.-Further reading:...
  
   
• GPR44
  GPR44
  G protein-coupled receptor 44 is a human protein. GPR44 has also been designated as CD294 .GPR44 has recently been found to belong to the prostanoid receptor family and named DP2, with this becoming the official IUPHAR nomenclature.-External links:...
  
   
• GPR77
  GPR77
  C5a anaphylatoxin chemotactic receptor C5L2 is a protein that in humans is encoded by the GPR77 gene.-Further reading:...
  
   

Subfamily A9

• Melatonin receptor
  Melatonin receptor
  A melatonin receptor is a G protein-coupled receptor which binds melatonin.Three types of melatonin receptor have been cloned. The MT1 and MT2 receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype MT3 has been identified in amphibia and...
  
   
  • Melatonin receptor 1A
    Melatonin receptor 1A
    Melatonin receptor type 1A is a protein that in humans is encoded by the MTNR1A gene.-Further reading:...
    
     
  • Melatonin receptor 1B
    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 the pineal gland. This gene product is an integral membrane...
    
     
• Neurokinin receptor
  Tachykinin receptor
  There are three known mammalian tachykinin receptors termed NK1, NK2 and NK3. All are members of the 7 transmembrane G-protein coupled receptor family and induce the activation of phospholipase C, producing inositol triphosphate ....
  
   
  • Tachykinin receptor 1
    Tachykinin receptor 1
    The tachykinin receptor 1 also known as neurokinin 1 receptor or substance P receptor is a G protein coupled receptor found in the central nervous system and peripheral nervous system. The endogenous ligand for this receptor is Substance P, although it has some affinity for other tachykinins...
    
     
  • Tachykinin receptor 2
    Tachykinin receptor 2
    Substance-K receptor is a protein that in humans is encoded by the TACR2 gene.-Selective Ligands:Several selective ligands for NK2 are now available, and although most of the compounds developed so far are peptides, one small-molecule antagonist Saredutant is currently in clinical trials as an...
    
     
  • Tachykinin receptor 3
    Tachykinin receptor 3
    Tachykinin receptor 3, also known as TACR3, is a protein which in humans is encoded by the TACR3 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 the sequence...
    
     
• Neuropeptide Y receptor
  Neuropeptide Y receptor
  Neuropeptide Y receptors are a class of G-protein coupled receptors which are activated by the closely related peptide hormones neuropeptide Y, peptide YY and pancreatic polypeptide...
  
   
  • Neuropeptide Y receptor Y1
    Neuropeptide Y receptor Y1
    Neuropeptide Y receptor type 1 is a protein that in humans is encoded by the NPY1R gene.-Antagonists:Peptide* BVD-10 * GR-231,118 Non-peptide...
    
     
  • Neuropeptide Y receptor Y2
    Neuropeptide Y receptor Y2
    Neuropeptide Y receptor type 2 is a protein that in humans is encoded by the NPY2R gene.-Agonists:* Neuropeptide Y * Neuropeptide Y fragment 13-36...
    
     
  • Pancreatic polypeptide receptor 1
    Pancreatic polypeptide receptor 1
    Neuropeptide Y receptor type 4 is a protein that in humans is encoded by the PPYR1 gene.-Agonists:* Pancreatic polypeptide* Neuropeptide Y * Peptide YY...
    
     
  • Neuropeptide Y receptor Y5
    Neuropeptide Y receptor Y5
    Neuropeptide Y receptor type 5 is a protein that in humans is encoded by the NPY5R gene.-Agonists:* Neuropeptide Y * BWX-46 * Peptide YY-Antagonists:...
    
     
• Prolactin-releasing peptide receptor
  Prolactin-releasing peptide receptor
  The prolactin-releasing hormone receptor is a G-protein coupled receptor that binds the prolactin releasing hormone....
  
   (PRLHR
  Gene
  A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
  
  , GPRA)
• Prokineticin receptor 1
  Prokineticin receptor 1
  Prokineticin receptor 1, also known as PKR1, is a human protein encoded by the PROKR1 gene.-Further reading:...
  
   
• GPR19
  GPR19
  Probable G-protein coupled receptor 19 is a protein that in humans is encoded by the GPR19 gene.-Further reading:...
  
   
• GPR50
  GPR50
  G protein-coupled receptor 50 is a protein which in humans is encoded by the GPR50 gene.- Function :GPR50 is a member of the G protein-coupled receptor family of integral membrane proteins and is most closely related to the melatonin receptor. GPR50 is able to heterodimerize with both the MT1 and...
  
   
• GPR75
  GPR75
  Probable G-protein coupled receptor 75 is a protein that in humans is encoded by the GPR75 gene.-Further reading:...
  
   
• GPR83
  GPR83
  Probable G-protein coupled receptor 83 is a protein that in humans is encoded by the GPR83 gene.-Further reading:...
  
   

Subfamily A10

• Glycoprotein hormone receptor
  • FSH-receptor
    FSH-receptor
    The follicle-stimulating hormone receptor or FSH-receptor is a transmembrane receptor that interacts with the follicle-stimulating hormone and represents a G protein-coupled receptor . Its activation is necessary for the hormonal functioning of FSH...
    
     
  • Luteinizing hormone/choriogonadotropin receptor
    Luteinizing hormone/choriogonadotropin receptor
    The luteinizing hormone/choriogonadotropin receptor , also lutropin/choriogonadotropin receptor or luteinizing hormone receptor is a transmembrane receptor found in the ovary, testis and extragonadal organs like the uterus...
    
     
  • Thyrotropin receptor
    Thyrotropin receptor
    The thyrotropin receptor is a receptor that responds to thyroid-stimulating hormone and stimulates the production of thyroxine and triiodothyronine...
    
     
• Leucine-rich repeat-containing G protein-coupled receptor 4
  LGR4
  Leucine-rich repeat-containing G-protein coupled receptor 4 is a protein that in humans is encoded by the LGR4 gene. LGR4 is known to have a role in the development of the male reproductive tract, eyelids, hair and bone.-Further reading:...
  
   ( , GPR48)
• Leucine-rich repeat-containing G protein-coupled receptor 5
  LGR5
  Leucine-rich repeat-containing G-protein coupled receptor 5 is a protein that in humans is encoded by the LGR5 gene. It is also known as GPR49....
  
   ( , GPR49)

Subfamily A11

• GPR40-related receptor
  Free fatty acid receptor
  The free fatty acid receptor is a G-protein coupled receptor which binds free fatty acids. There are four variants of the receptor, each encoded by a separate gene ....
  
   
  • Free fatty acid receptor 1
    Free fatty acid receptor 1
    Free fatty acid receptor 1, is a G-protein coupled receptor encoded by the human gene FFAR1. It is strongly expressed in the cells of the pancreas, but also, to a lesser extent, the uterus and brain.-Further reading:...
    
     
  • Free fatty acid receptor 2
    Free fatty acid receptor 2
    Free fatty acid receptor 2 is a G-protein coupled receptor encoded by the FFAR2 gene.-Further reading:...
    
     
  • Free fatty acid receptor 3
    Free fatty acid receptor 3
    Free fatty acid receptor 3 is a G-protein coupled receptor that in humans is encoded by the FFAR3 gene.-Further reading:...
    
     
  • GPR42
    GPR42
    Putative G-protein coupled receptor 42 is a protein that in humans is encoded by the GPR42P gene.-Further reading:...
    
     
• P2 purinoceptor
  P2Y receptor
  P2Y receptors are a family of purinergic receptors, G protein-coupled receptors stimulated by nucleotides such as ATP, ADP, UTP, UDP and UDP-glucose...
  
   
  • Purinergic receptor P2Y₁
    P2RY1
    P2Y purinoceptor 1 is a protein that in humans is encoded by the P2RY1 gene.-Further reading:...
    
     
  • Purinergic receptor P2Y₂
    P2RY2
    P2Y purinoceptor 2 is a protein that in humans is encoded by the P2RY2 gene.-Further reading:...
    
     
  • Purinergic receptor P2Y₄
    P2RY4
    P2Y purinoceptor 4 is a protein that in humans is encoded by the P2RY4 gene.-Further reading:...
    
     
  • Purinergic receptor P2Y₆
    P2RY6
    P2Y purinoceptor 6 is a protein that in humans is encoded by the P2RY6 gene.-Further reading:-External links:...
    
     
  • Purinergic receptor P2Y₁₁
    P2RY11
    P2Y purinoceptor 11 is a protein that in humans is encoded by the P2RY11 gene.-Further reading:...
    
     
• GPR31
  GPR31
  Probable G-protein coupled receptor 31 is a protein that in humans is encoded by the GPR31 gene.-Further reading:...
  
   
• GPR81
  GPR81
  G protein-coupled receptor 81, also known as GPR81, is a protein that in humans is encoded by the GPR81 gene.G protein-coupled receptors , such as GPR81, contain 7 transmembrane domains and transduce extracellular signals through heterotrimeric G proteins.Lactate activates the GPR81 receptor which...
  
   
• GPR82
  GPR82
  Probable G-protein coupled receptor 82 is a protein that in humans is encoded by the GPR82 gene.-Further reading:...
  
   
• GPR109B
  GPR109B
  Niacin receptor 2, also known as NIACR2 or GPR109B, is a protein which in humans is encoded by the NIACR2 gene.- Function :GPR109B is a low affinity receptor for nicotinic acid and is a member of the nicotinic acid receptor family of G protein-coupled receptors .GPR109B is a Gi /Go protein-coupled...
  
   
• Oxoglutarate (alpha-ketoglutarate) receptor 1
  OXGR1
  2-oxoglutarate receptor 1 is a protein that in humans is encoded by the OXGR1 gene.-Further reading:...
  
   
• Succinate receptor 1
  SUCNR1
  Succinate receptor 1 is a protein that in humans is encoded by the SUCNR1 gene.-Further reading:...
  
   

Subfamily A12

• P2 purinoceptor
  P2Y receptor
  P2Y receptors are a family of purinergic receptors, G protein-coupled receptors stimulated by nucleotides such as ATP, ADP, UTP, UDP and UDP-glucose...
  
   
  • Purinergic receptor P2Y₁₂
    P2Y12
    In the field of molecular biology, the P2Y12 protein is found mainly but not only on the surface of blood platelet cells and is an important regulator in blood clotting....
    
     
  • Purinergic receptor P2Y₁₃
    P2RY13
    P2Y purinoceptor 13 is a protein that in humans is encoded by the P2RY13 gene.-Further reading:...
    
     
  • Purinergic receptor P2Y₁₄
    P2RY14
    P2Y purinoceptor 14 is a protein that in humans is encoded by the P2RY14 gene.-Further reading:...
    
     
• GPR34
  GPR34
  Probable G-protein coupled receptor 34 is a protein that in humans is encoded by the GPR34 gene.-Further reading:...
  
   
• GPR87
  GPR87
  Probable G-protein coupled receptor 87 is a protein that in humans is encoded by the GPR87 gene.-Further reading:...
  
   
• GPR171
  GPR171
  Probable G-protein coupled receptor 171 is a protein that in humans is encoded by the GPR171 gene.-Further reading:...
  
   
• Platelet-activating factor receptor
  Platelet-activating factor receptor
  The platelet-activating factor receptor is a G-protein coupled receptor which binds platelet-activating factor.-External links:...
  
   

Subfamily A13

• Cannabinoid receptor
  Cannabinoid receptor
  The cannabinoid receptors are a class of cell membrane receptors under the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cannabinoid receptors contain seven transmembrane spanning domains...
  
   
  • Cannabinoid receptor 1 (brain) 
  • Cannabinoid receptor 2 (macrophage)
    Cannabinoid receptor 2 (macrophage)
    Cannabinoid receptor 2 , also known as CB2 or CNR2, is a G protein-coupled receptor from the cannabinoid receptor family, which in humans is encoded by the CNR2 gene...
    
     
• Lysophosphatidic acid receptor
  Lysophospholipid receptor
  The lysophospholipid receptor group are members of the G protein-coupled receptor family of integral membrane proteins that are important for lipid signaling. In humans, there are eight LPL receptors, each encoded by a separate gene...
  
   
  • Endothelial differentiation gene 2
    EDG2
    Lysophosphatidic acid receptor 1 also known as LPA1 is a protein that in humans is encoded by the LPAR1 gene. LPA1 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid .- Function :...
    
     
  • Endothelial differentiation gene 4
    EDG4
    Lysophosphatidic acid receptor 2 also known as LPA2 is a protein that in humans is encoded by the LPAR2 gene. LPA2 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid .- Function :...
    
     
  • Endothelial differentiation gene 7
    EDG7
    Lysophosphatidic acid receptor 3 also known as LPA3 is a protein that in humans is encoded by the LPAR3 gene. LPA3 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid .- Function :...
    
     
• Sphingosine 1-phosphate receptor
  Lysophospholipid receptor
  The lysophospholipid receptor group are members of the G protein-coupled receptor family of integral membrane proteins that are important for lipid signaling. In humans, there are eight LPL receptors, each encoded by a separate gene...
  
   
  • Endothelial differentiation gene 1
    EDG1
    S1PR1 also known as S1P1 or EDG1 is a protein that in humans is encoded by the S1PR1 gene...
    
     
  • Endothelial differentiation gene 3
    EDG3
    Sphingosine-1-phosphate receptor 3 also known as S1PR3 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate . Hence this receptor is also known as S1P3.- Function :...
    
     
  • Endothelial differentiation gene 5
    EDG5
    Sphingosine-1-phosphate receptor 2 also known as S1PR2 or S1P2 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate .- Function :...
    
     
  • Endothelial differentiation gene 6
    EDG6
    Sphingosine-1-phosphate receptor 4 also known as S1PR4 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate . Hence this receptor is also known as S1P4.- Function :...
    
     
  • Endothelial differentiation gene 8
    EDG8
    Sphingosine-1-phosphate receptor 5 also known as S1PR5 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate . Hence this receptor is also known as S1P5....
    
     
• Melanocortin/ACTH receptor
  Melanocortin receptor
  Melanocortin receptors are members of the rhodopsin family of 7-transmembrane, G protein-coupled receptors.There are five known members of the melanocortin receptor system each with differing specificities for melanocortins:...
  
   
  • Melanocortin 1 receptor
    Melanocortin 1 receptor
    The melanocortin 1 receptor , also known as melanocyte-stimulating hormone receptor , melanin-activating peptide receptor, or melanotropin receptor, is a G protein-coupled receptor which binds to a class of pituitary peptide hormones known as the melanocortins, of which include adrenocorticotropic...
    
     
  • Melanocortin 3 receptor
    Melanocortin 3 receptor
    Melanocortin receptor 3 is a protein that in humans is encoded by the MC3R gene.-Further reading:...
    
     
  • Melanocortin 4 receptor
    Melanocortin 4 receptor
    Melanocortin receptor 4 is a protein that in humans is encoded by the MC4R gene. It encodes the MC4 protein, a G-protein coupled receptor that binds α-melanocyte stimulating hormone...
    
     
  • Melanocortin 5 receptor
    Melanocortin 5 receptor
    Melanocortin receptor 5 is a protein that in humans is encoded by the MC5R gene. It is located on the chromosome 18 in the human genome. When the melanocortin 5 receptor was disrupted in transgenic mice, it induced disruption of their exocrine glands and resulted in decreased production of...
    
     
  • ACTH receptor
    ACTH receptor
    The ACTH receptor is a type of melanocortin receptor , properly known as MC2, which is specific for ACTH.It is found in the zona fasciculata of the human adrenal cortex. Binding of the receptor by ACTH stimulates the production of cortisol...
    
     , ACTR)
• GPR3
  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.-Function:...
  
   
• GPR6
  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...
  
   
• GPR12
  GPR12
  Probable G-protein coupled receptor 12 is a protein that in humans is encoded by the GPR12 gene.-Further reading:...
  
   

Subfamily A14

• Eicosanoid receptor
  Eicosanoid receptor
  An eicosanoid receptor is an integral membrane protein which detects the presence of eicosanoid signaling molecules. Most, though not all, are G protein-coupled receptors...
  
   
  • Prostaglandin D₂ receptor
    Prostaglandin D2 receptor
    Prostaglandin D2 receptor is a G-protein coupled receptor, encoded by the PTGDR gene, for prostaglandin D2.-Mechanism:DP1 is a G-protein-coupled receptor...
    
     
  • Prostaglandin E₁ receptor  
  • Prostaglandin E₂ receptor
    Prostaglandin E2 receptor
    Prostaglandin E2 receptor , also known as EP2, is a prostaglandin receptor for prostaglandin E2. It is encoded by the human gene PTGER2.It may be associated with aspirin-induced asthma.-Mechanism:...
    
     
  • Prostaglandin E₃ receptor 
  • Prostaglandin E₄ receptor 
  • Prostaglandin F receptor 
  • Prostaglandin I₂ (prostacyclin) receptor 
  • Thromboxane A₂ receptor
    Thromboxane receptor
    The thromboxane receptor is a protein on the surface of cells in the endothelium of blood vessels and in the placenta which interacts with the eicosanoid lipid thromboxane. It is a G-protein coupled receptor coupled to the G protein Gq.-Gene:...
    
     

Subfamily A15

• P2 purinoceptor
  P2Y receptor
  P2Y receptors are a family of purinergic receptors, G protein-coupled receptors stimulated by nucleotides such as ATP, ADP, UTP, UDP and UDP-glucose...
  
   
  • Purinergic receptor P2Y₅
    P2RY5
    Lysophosphatidic acid receptor 6 also known as LPA6 and P2RY5 is a protein that in humans is encoded by the LPAR6 gene. LPA6 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid ....
    
     
  • Purinergic receptor P2Y₁₀
    P2RY10
    Putative P2Y purinoceptor 10 is a protein that in humans is encoded by the P2RY10 gene.-Further reading:...
    
     
• Protease-activated receptor
  Protease-activated receptor
  Protease-activated receptors 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, but also on endothelial cells, myocytes and neurons....
  
   
  • Coagulation factor II (thrombin) receptor-like 1
    F2RL1
    Protease activated receptor 2 or Coagulation factor II receptor-like 1, is a protein encoded by the ' gene in humans....
    
     
  • Coagulation factor II (thrombin) receptor-like 2
    F2RL2
    Protease activated receptor 3 , previously known as Coagulation factor II receptor-like 2, is a protein encoded by the F2RL2 gene in humans .-Further reading:...
    
     
• Epstein-Barr virus induced gene 2 (lymphocyte-specific G protein-coupled receptor) 
• Proton-sensing G protein-coupled receptors
  Proton-sensing G protein-coupled receptors
  Proton-sensing G protein-coupled receptors are transmembrane receptors which sense acidic pH and include G2A, GPR4, OGR1 and TDAG8. These G protein-coupled receptors are activated when extracellular pH falls into the range of 6.4-6.8...
  
  
  • GPR4
    GPR4
    G-protein coupled receptor 4 is a protein that in humans is encoded by the GPR4 gene.-Further reading:...
    
     
  • GPR65
    GPR65
    Psychosine receptor is a protein that in humans is encoded by the GPR65 gene.-Further reading:...
    
     
  • GPR68
    GPR68
    Ovarian cancer G-protein coupled receptor 1 is a protein that in humans is encoded by the GPR68 gene.-Further reading:...
    
     
  • GPR132
    GPR132
    Probable G-protein coupled receptor 132 is a protein that in humans is encoded by the GPR132 gene.-Further reading:...
    
     
• GPR17
  GPR17
  Uracil nucleotide/cysteinyl leukotriene receptor is a protein that in humans is encoded by the GPR17 gene.-Further reading:*M. Kandhavelu, M. P. Abbracchio, P. Angeli, M. Buccioni, D. Dal Ben, C. Lammi, D. Lecca, G. Marucci, G. Cristalli...
  
   
• GPR18
  GPR18
  N-arachidonyl glycine receptor also known as G-protein coupled receptor 18 is a protein that in humans is encoded by the GPR18 gene...
  
   
• GPR20
  GPR20
  Probable G-protein coupled receptor 20 is a protein that in humans is encoded by the GPR20 gene.-Further reading:...
  
   
• GPR23
  GPR23
  Lysophosphatidic acid receptor 4 also known as LPA4 is a protein that in humans is encoded by the LPAR4 gene. LPA4 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid .-Further reading:...
  
   
• GPR35
  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 Lieberkühn....
  
   
• GPR55
  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 :...
  
   
• GPR92
  GPR92
  Lysophosphatidic acid receptor 5 also known as LPA5 is a protein that in humans is encoded by the LPAR5 gene. LPA5 is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid .-Further reading:...
  
   
• Coagulation factor II receptor
  Coagulation factor II receptor
  Proteinase-activated receptor 1 also known as the coagulation factor II receptor is a protein that in humans is encoded by the F2R gene. PAR1 is a G protein-coupled receptor involved in the regulation of thrombotic response...
  
   

Subfamily A16

• Opsin
  Opsin
  Opsins are a group of light-sensitive 35–55 kDa membrane-bound G protein-coupled receptors of the retinylidene protein family found in photoreceptor cells of the retina. Five classical groups of opsins are involved in vision, mediating the conversion of a photon of light into an electrochemical...
  
  s
  • Rhodopsin
    Rhodopsin
    Rhodopsin, also known as visual purple, is a biological pigment of the retina that is responsible for both the formation of the photoreceptor cells and the first events in the perception of light. Rhodopsins belong to the G-protein coupled receptor family and are extremely sensitive to light,...
    
     
  • Opsin 1 (cone pigments), short-wave-sensitive (color blindness, tritan)
    OPN1SW
    Blue-sensitive opsin is a protein that in humans is encoded by the OPN1SW gene.-Further reading:...
    
      (blue-sensitive opsin)
  • Opsin 1 (cone pigments), medium-wave-sensitive (color blindness, deutan)
    OPN1MW
    Green-sensitive opsin is a protein that in humans is encoded by the OPN1MW gene.-External links:* -Further reading:...
    
      (green-sensitive opsin)
  • Opsin 1 (cone pigments), long-wave-sensitive (color blindness, protan)
    OPN1LW
    Red-sensitive opsin is a protein that in humans is encoded by the OPN1LW gene.-External links:* -Further reading:...
    
      (red-sensitive opsin)
  • Retinal G protein coupled receptor
    Retinal G protein coupled receptor
    RPE-retinal G protein-coupled receptor is a protein that in humans is encoded by the RGR gene.-Interactions:Retinal G protein coupled receptor has been shown to interact with KIAA1279.-Further reading:...
    
     
  • Retinal pigment epithelium-derived rhodopsin homolog
    RRH
    Visual pigment-like receptor peropsin is a protein that in humans is encoded by the RRH gene.-Further reading:...
    
      (visual pigment-like receptor opsin)

Subfamily A17

• 5-Hydroxytryptamine (5-HT) receptor
  5-HT receptor
  The serotonin receptors, also known as 5-hydroxytryptamine receptors or 5-HT receptors, are a group of G protein-coupled receptors and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission...
  
   
  • 5-HT_2A
    5-HT2A receptor
    The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...
    
     
  • 5-HT_2B
    5-HT2B receptor
    5-hydroxytryptamine receptor 2B, also known as HTR2B, is a 5-HT2 receptor, but also denotes the human gene encoding it.-Function:...
    
     
  • 5-HT_2C
    5-HT2C receptor
    The 5-HT2C receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor that is coupled to Gq/G11 and mediates excitatory neurotransmission. HTR2C denotes the human gene encoding for the receptor, that in humans is located at the...
    
     
  • 5-HT₆
    5-HT6 receptor
    The 5-HT6 receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor that is coupled to Gs/Go and mediates excitatory neurotransmission. HTR6 denotes the human gene encoding for the receptor.-Distribution:The 5-HT6 receptor is...
    
     
• Adrenergic receptor
  Adrenergic receptor
  The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
  
   
  • Alpha_1A
    Alpha-1A adrenergic receptor
    The alpha-1A adrenergic receptor , also known as ADRA1A, formerly known as the alpha-1C adrenergic receptor, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.-Agonists:...
    
     
  • Alpha_1B
    Alpha-1B adrenergic receptor
    The alpha-1B adrenergic receptor , also known as ADRA1B, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.-Interactions:...
    
     
  • Alpha_1D
    Alpha-1D adrenergic receptor
    The alpha-1D adrenergic receptor , also known as ADRA1D, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.-Further reading:...
    
     
  • Alpha_2A
    Alpha-2A adrenergic receptor
    The alpha-2A adrenergic receptor , also known as ADRA2A, is an alpha-2 adrenergic receptor, and also denotes the human gene encoding it.-Role in Central Nervous System:...
    
     
  • Alpha_2B
    Alpha-2B adrenergic receptor
    The alpha-2B adrenergic receptor , is a G-protein coupled receptor. It is a subtype of the adrenergic receptor family. The human gene encoding this receptor has the symbol ADRA2B.ADRA2B orthologs have been identified in several mammals....
    
     
  • Alpha_2C
    Alpha-2C adrenergic receptor
    The alpha-2C adrenergic receptor , also known as ADRA2C, is an alpha-2 adrenergic receptor, and also denotes the human gene encoding it.-Agonists:* -3-Nitrobiphenyline -Antagonists:...
    
     
  • Beta₁
    Beta-1 adrenergic receptor
    The beta-1 adrenergic receptor , also known as ADRB1, is a beta-adrenergic receptor, and also denotes the human gene encoding it...
    
     
  • Beta₂
    Beta-2 adrenergic receptor
    The beta-2 adrenergic receptor , also known as ADRB2, is a beta-adrenergic receptor, and also denotes the human gene encoding it.-Gene:The gene is intronless...
    
     
  • Beta₃
    Beta-3 adrenergic receptor
    The beta-3 adrenergic receptor , also known as ADRB3, is an beta-adrenergic receptor, and also denotes the human gene encoding it.-Function:Actions of the β3 receptor include:*Enhancement of lipolysis in adipose tissue....
    
     
• Dopamine receptor
  Dopamine receptor
  Dopamine receptors are a class of metabotropic G protein-coupled receptors that are prominent in the vertebrate central nervous system . The neurotransmitter dopamine is the primary endogenous ligand for dopamine receptors....
  
   
  • D₁
    Dopamine receptor D1
    Dopamine receptor D1, also known as DRD1, is a protein that in humans is encoded by the DRD1 gene.- Function :This gene encodes the D1 subtype of the dopamine receptor. The D1 subtype is the most abundant dopamine receptor in the central nervous system. This G-protein-coupled receptor stimulates...
    
     
  • D₂
    Dopamine receptor D2
    Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene.- Function :This gene encodes the D2 subtype of the dopamine receptor. This G protein-coupled receptor inhibits adenylyl cyclase activity...
    
     
  • D₃
    Dopamine receptor D3
    D dopamine receptor is a protein that in humans is encoded by the DRD3 gene.This gene encodes the D3 subtype of the dopamine receptor. The D3 subtype inhibits adenylyl cyclase through inhibitory G-proteins. This receptor is expressed in phylogenetically older regions of the brain, suggesting that...
    
     
  • D₄ 
  • D₅
    Dopamine receptor D5
    D dopamine receptor is a protein that in humans is encoded by the DRD5 gene.This gene encodes the D5 subtype of the dopamine receptor. The D5 subtype is a G-protein coupled receptor which stimulates adenylyl cyclase. This receptor is expressed in neurons in the limbic regions of the brain. It has a...
    
     
• Octopamine
  Octopamine
  Octopamine is an endogenous biogenic amine that is closely related to norepinephrine, and has effects on the adrenergic and dopaminergic systems. It is also found naturally in numerous plants, including bitter orange. Biosynthesis of the D--enantiomer of octopamine is by β-hydroxylation of...
  
   receptor
• Trace amine receptor 
  • TAAR2
    TAAR2
    Trace amine-associated receptor 2 is a protein that in humans is encoded by the TAAR2 gene.-Further reading:...
    
     
  • TAAR3
    TAAR3
    Putative trace amine-associated receptor 3 is a protein that in humans is encoded by the TAAR3 gene.-Further reading:...
    
     
  • TAAR5
    TAAR5
    Trace amine-associated receptor 5 is a protein that in humans is encoded by the TAAR5 gene.-Further reading:...
    
     
  • TAAR8
    TAAR8
    Trace amine-associated receptor 8 is a protein that in humans is encoded by the TAAR8 gene.-Further reading:...
    
     
• Histamine H₂ receptor 

Subfamily A18

• Histamine H₁ receptor 
• Histamine H₃ receptor 
• Histamine H₄ receptor 
• Adenosine receptor
  Adenosine receptor
  The adenosine receptors are a class of purinergic receptors, G protein-coupled receptors with adenosine as endogenous ligand.-Pharmacology:...
  
   
  • A₁ 
  • A_2a
    Adenosine A2A receptor
    The adenosine A2A receptor, also known as ADORA2A, is an adenosine receptor, but also denotes the human gene encoding it.-Structure:This protein is a member of the G protein-coupled receptor family which possess seven transmembrane alpha helices...
    
     
  • A_2b
    Adenosine A2b receptor
    The adenosine A2B receptor, also known as ADORA2B, is a G-protein coupled adenosine receptor, and also denotes the human adenosine A2b receptor gene which encodes it....
    
     
  • A₃
    Adenosine A3 receptor
    The adenosine A3 receptor, also known as ADORA3, is an adenosine receptor, but also denotes the human gene encoding it.- Function :Adenosine A3 receptors are G protein-coupled receptors that couple to Gi/Gq and are involved in a variety of intracellular signaling pathways and physiological functions...
    
     
• Muscarinic acetylcholine receptor
  Muscarinic acetylcholine receptor
  Muscarinic receptors, or mAChRs, are acetylcholine receptors that form G protein-coupled in the plasma membranes of certain neurons and other cells...
  
   
  • M₁
    Muscarinic acetylcholine receptor M1
    The muscarinic acetylcholine receptor M1, also known as the cholinergic receptor, muscarinic 1, is a muscarinic receptor.This receptor is found mediating slow EPSP at the ganglion in the postganglionic nerve, is common in exocrine glands and in the CNS.It is predominantly found bound to G proteins...
    
     
  • M₂
    Muscarinic acetylcholine receptor M2
    The muscarinic acetylcholine receptor M2, also known as the cholinergic receptor, muscarinic 2, is a muscarinic acetylcholine receptor.-Heart:...
    
     
  • M₃
    Muscarinic acetylcholine receptor M3
    The muscarinic acetylcholine receptor M3, also known as the cholinergic receptor, muscarinic 3, is a muscarinic acetylcholine receptor. It is encoded by the human gene CHRM3....
    
     
  • M₄
    Muscarinic acetylcholine receptor M4
    The muscarinic acetylcholine receptor M4, also known as the cholinergic receptor, muscarinic 4 , is a protein that, in humans, is encoded by the CHRM4 gene.-Function:...
    
     
  • M₅
    Muscarinic acetylcholine receptor M5
    The human muscarinic acetylcholine receptor M5 which is encoded by the gene is a member of the G protein-coupled receptor superfamily of integral membrane proteins. Binding of the endogenous ligand acetylcholine to the M5 receptor triggers a number of cellular responses such as adenylate cyclase...
    
     
• GPR21
  GPR21
  Probable G-protein coupled receptor 21 is a protein that in humans is encoded by the GPR21 gene.-Further reading:...
  
   
• GPR27
  GPR27
  Probable G-protein coupled receptor 27 is a protein that in humans is encoded by the GPR27 gene.-Further reading:...
  
   
• GPR45
  GPR45
  Probable G-protein coupled receptor 45 is a protein that in humans is encoded by the GPR45 gene.-Further reading:...
  
   
• GPR52
  GPR52
  Probable G-protein coupled receptor 52 is a protein that in humans is encoded by the GPR52 gene.-Further reading:...
  
   
• GPR61
  GPR61
  Probable G-protein coupled receptor 61 is a protein that in humans is encoded by the GPR61 gene....
  
   
• GPR62
  GPR62
  Probable G-protein coupled receptor 62 is a protein that in humans is encoded by the GPR62 gene.-Further reading:...
  
   
• GPR63
  GPR63
  Probable G-protein coupled receptor 63 is a protein that in humans is encoded by the GPR63 gene.-Further reading:...
  
   
• GPR78
  GPR78
  Probable G-protein coupled receptor 78 is a protein that in humans is encoded by the GPR78 gene.-Further reading:...
  
   
• GPR84
  GPR84
  Probable G-protein coupled receptor 84 is a protein that in humans is encoded by the GPR84 gene.-Further reading:...
  
   
• GPR85
  GPR85
  Probable G-protein coupled receptor 85 is a protein that in humans is encoded by the GPR85 gene.-Further reading:...
  
   
• GPR88
  GPR88
  Probable G-protein coupled receptor 88 is a protein that in humans is encoded by the GPR88 gene....
  
   
• GPR101
  GPR101
  Probable G-protein coupled receptor 101 is a protein that in humans is encoded by the GPR101 gene.-Further reading:...
  
   
• GPR161
  GPR161
  G-protein coupled receptor 161 is a protein that in humans is encoded by the GPR161 gene.-Further reading:...
  
   
• GPR173
  GPR173
  Probable G-protein coupled receptor 173 is a protein that in humans is encoded by the GPR173 gene.-Further reading:...
  
   

Subfamily A19

• 5-Hydroxytryptamine (5-HT) receptor
  5-HT receptor
  The serotonin receptors, also known as 5-hydroxytryptamine receptors or 5-HT receptors, are a group of G protein-coupled receptors and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission...
  
   
  • 5-HT_1A
    5-HT1A receptor
    The 5-HT1A receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor that is coupled to Gi/Go and mediates inhibitory neurotransmission...
    
     
  • 5-HT_1B
    5-HT1B receptor
    5-hydroxytryptamine receptor 1B also known as the 5-HT1B receptor is a protein that in humans is encoded by the HTR1B gene. The 5-HT1B receptor is a 5-HT receptor subtype.-Tissue distribution and function:...
    
     
  • 5-HT_1D
    5-HT1D receptor
    5-hydroxytryptamine receptor 1D, also known as HTR1D, is a 5-HT receptor, but also denotes the human gene encoding it. 5-HT1D acts on the central nervous system, and affects locomotion and anxiety...
    
     
  • 5-HT_1E
    5-HT1E receptor
    5-hydroxytryptamine 1E receptor is a highly expressed human G-protein coupled receptor that belongs to the 5-HT1 receptor family . The human gene is denoted as HTR1E.-Function:...
    
     
  • 5-HT_1F 
  • 5-HT₄
    5-HT4 receptor
    5-hydroxytryptamine receptor 4 is a protein that in humans is encoded by the HTR4 gene.- Location :The receptor is located in the alimentary tract, urinary bladder, heart and adrenal gland as well as the central nervous system ....
    
     
  • 5-HT_5A
    5-HT5A receptor
    5-hydroxytryptamine receptor 5A, also known as HTR5A, is a protein which in humans is encoded by the HTR5A gene.- Function :...
    
     
  • 5-HT₇
    5-HT7 receptor
    The 5-HT7 receptor is a member of the GPCR superfamily of cell surface receptors and is activated by the neurotransmitter serotonin The 5-HT7 receptor is coupled to Gs and is expressed in a variety of human tissues, particularly in the brain, the gastrointestinal tract, and in various...
    
     

Unclassified

• Olfactory receptor
  Olfactory receptor
  Olfactory receptors expressed in the cell membranes of olfactory receptor neurons are responsible for the detection of odor molecules. Activated olfactory receptors are the initial player in a signal transduction cascade which ultimately produces a nerve impulse which is transmitted to the brain...
  
   
• Vomeronasal receptor
  • VN1R1
    VN1R1
    Vomeronasal type-1 receptor 1 is a protein that in humans is encoded by the VN1R1 gene.-Further reading:...
    
    
  • VN1R2
    VN1R2
    Vomeronasal type-1 receptor 2 is a protein that in humans is encoded by the VN1R2 gene.-Further reading:...
    
    
  • VN1R3
    VN1R3
    Vomeronasal type-1 receptor 3 is a protein that in humans is encoded by the VN1R3 gene.-Further reading:...
    
    
  • VN1R4
    VN1R4
    Vomeronasal type-1 receptor 4 is a protein that in humans is encoded by the VN1R4 gene.-Further reading:...
    
    
  • VN1R5
    VN1R5
    Vomeronasal type-1 receptor 5 is a protein that in humans is encoded by the VN1R5 gene.-Further reading:...
    
    

External links

This database includes multiple sequence alignments of all GPCR families and sub-families.