Orphan and other 7TM receptors

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Class A Orphans

Overview

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Table 1 lists a number of putative GPCRs identified by IUPHAR [28], for which preliminary evidence for an endogenous ligand has been published, or for which there exists a potential link to a disease, or disorder. The GPCRs in Table 1 are all Class A, rhodopsin-like GPCRs. Class A orphan GPCRs not listed in Table 1 are putative GPCRs with as-yet unidentified endogenous ligands.

Table 1: Class A orphan GPCRs with putative endogenous ligands

GPR1	GPR3	GPR4	GPR6	GPR12	GPR15	GPR17	GRP20
GPR22	GPR26	GPR31	GPR34	GPR35	GPR37	GPR39	GPR50
GPR63	GRP65	GPR68	GPR75	GPR84	GPR87	GPR88	GPR132
GPR149	GPR161	GPR183	LGR4	LGR5	LGR6	MAS1	MRGPRD
MRGPRX1	MRGPRX2	P2RY10	TAAR2

In addition the orphan receptors GPR18, GPR55 and GPR119 which are reported to respond to endogenous agents analogous to the endogenous cannabinoid ligands have been grouped together (GPR18, GPR55 and GPR119).

Receptors

BB₃ receptor Show summary »« Hide summary More detailed page

GPR1 Show summary »« Hide summary More detailed page

Nomenclature

GPR1

Previous and unofficial names

GPR1, G-protein coupled receptor 1, probable G-protein coupled receptor 1, G protein-coupled receptor 1

Genes

GPR1 (Hs), Gpr1 (Mm), Gpr1 (Rn)

Ensembl ID

ENSG00000183671 (Hs), ENSMUSG00000046856 (Mm), ENSRNOG00000045532 (Rn)

UniProtKB AC

P46091 (Hs), Q8K087 (Mm), P46090 (Rn)

Principal transduction

Endogenous agonists
(pK_i)

chemerin (RARRES2, Q99969) (pK_d 8.28) [2]

Comment

Reported to act as a co-receptor for HIV [106].

GPR3 Show summary »« Hide summary More detailed page

Nomenclature	GPR3
Previous and unofficial names	GPCR3, Gpcr21, ACCA, GPR3, G-protein coupled receptor 3, ACCA orphan receptor, adenylate cyclase constitutive activator, G protein-coupled receptor 3, G protein-coupled receptor R4, G-protein-coupled receptor R4, Gpcr20
Genes	GPR3 (Hs), Gpr3 (Mm), Gpr3 (Rn)
Ensembl ID	ENSG00000181773 (Hs), ENSMUSG00000049649 (Mm), ENSRNOG00000009540 (Rn)
UniProtKB AC	P46089 (Hs), P35413 (Mm), Q8K1Q3 (Rn)
Principal transduction	G_s
Comment	sphingosine 1-phosphate was reported to be an endogenous agonist [117], but this finding was not replicated in subsequent studies [128]. Reported to activate adenylyl cyclase constitutively through G_s [25]. Gene disruption results in premature ovarian aging [63], reduced β-amyloid deposition [116] and hypersensitivity to thermal pain [100] in mice.

GPR4 Show summary »« Hide summary More detailed page

Nomenclature	GPR4
Previous and unofficial names	MGC116369, GPR4, G-protein coupled receptor 4, G-protein coupled receptor 19, GPR19, Gpr4_predicted, LOC308408, G protein-coupled receptor 4, G protein-coupled receptor 4 (predicted)
Genes	GPR4 (Hs), Gpr4 (Mm), Gpr4 (Rn)
Ensembl ID	ENSG00000177464 (Hs), ENSMUSG00000044317 (Mm), ENSRNOG00000016362 (Rn)
UniProtKB AC	P46093 (Hs), Q8BUD0 (Mm), Q4KLH9 (Rn)
Principal transduction	G_s
Endogenous ligand	Protons
Comment	An initial report suggesting activation by lysophosphatidylcholine and sphingosylphosphorylcholine [134] has been retracted [135]. GPR4, GPR65, GPR68 and GPR132 are now thought to function as protein-sensing receptors detecting acidic pH [20,105]. Gene disruption is associated with increased perinatal mortality and impaired vascular proliferation [126].

GPR6 Show summary »« Hide summary More detailed page

Nomenclature	GPR6
Previous and unofficial names	Sphingosine 1-phosphate receptor GPR6, GPR6, G-protein coupled receptor 6, Sphingosine 1-phosphate receptor, G protein-coupled receptor 6, putative G protein-coupled receptor (CNL3), AI852874, Gm233
Genes	GPR6 (Hs), Gpr6 (Mm), Gpr6 (Rn)
Ensembl ID	ENSG00000146360 (Hs), ENSMUSG00000046922 (Mm), ENSRNOG00000049580 (Rn)
UniProtKB AC	P46095 (Hs), Q6YNI2 (Mm), P51651 (Rn)
Principal transduction	G_s
Comment	An initial report that sphingosine 1-phosphate (S1P) was a high-affinity ligand (EC₅₀ value of 39nM) [41,117] was not repeated by β-Arrestin PathHunter[TM] assays [110,128]. Reported to activate adenylyl cyclase constitutively through G_s and to be located intracellularly [92]. Gpr6-deficient mice showed reduced striatal cyclic AMP production in vitro and selected alterations in instrumental conditioning in vitro. [71].

GPR12 Show summary »« Hide summary More detailed page

Nomenclature	GPR12
Previous and unofficial names	MGC156481, Gpcr12, Gpcr01, Gpcr20, GPCR21, GPR12, G-protein coupled receptor 12, GPCR12, R334
Genes	GPR12 (Hs), Gpr12 (Mm), Gpr12 (Rn)
Ensembl ID	ENSG00000132975 (Hs), ENSMUSG00000041468 (Mm), ENSRNOG00000039832 (Rn)
UniProtKB AC	P47775 (Hs), P35412 (Mm), P30951 (Rn)
Principal transduction	-
Comment	Reports that sphingosine 1-phosphate was a ligand of GPR12 [40,117] have not been replicated in β-arrestin-based assays [110,128]. Gene disruption results in dyslipidemia and obesity [7].

GPR15 Show summary »« Hide summary More detailed page

Nomenclature	GPR15
Previous and unofficial names	BOB, GPR15, G protein-coupled receptor 15, Brother of Bonzo, G-protein coupled receptor 15, Gpr15_predicted, LOC288181, G protein-coupled receptor 15 (predicted), 4933439K08Rik, BoB
Genes	GPR15 (Hs), Gpr15 (Mm), Gpr15 (Rn)
Ensembl ID	ENSG00000154165 (Hs), ENSMUSG00000047293 (Mm), ENSRNOG00000039680 (Rn)
UniProtKB AC	P49685 (Hs), Q0VDU3 (Mm)
Principal transduction	-
Comment	Reported to act as a co-receptor for HIV [23]. In an infection-induced colitis model, Gpr15 knockout mice were more prone to tissue damage and inflammatory cytokine expression [53].

GPR17 Show summary »« Hide summary More detailed page

Nomenclature

GPR17

Previous and unofficial names

Uracil nucleotide/cysteinyl leukotriene receptor, UDP/CysLT receptor, P2Y-like receptor, R12, GPR17, G-protein coupled receptor 17, G protein-coupled receptor 17, uracil nucleotide/cysteinyl leukotriene receptor, AI853548

Genes

GPR17 (Hs), Gpr17 (Mm), Gpr17 (Rn)

Ensembl ID

ENSG00000144230 (Hs), ENSMUSG00000052229 (Mm), ENSRNOG00000025745 (Rn)

UniProtKB AC

Q13304 (Hs), Q6NS65 (Mm), Q09QM4 (Rn)

Principal transduction

Endogenous agonists
(pK_i)

LTC₄ (pEC₅₀ 7.83 – 9.48) [19]

LTD₄ (pEC₅₀ 8.14 – 8.36) [19]

UDP-glucose (pEC₅₀ 5.92 – 9.52) [6,19]

UDP-galactose (pEC₅₀ 5.96 – 8.92) [6,19]

UDP (pEC₅₀ 5.97 – 8.8) [6,19]

Comment

Reported to be a dual leukotriene and UDP receptor [19]. Another group instead proposed that GPR17 functions as a negative regulator of the CysLT₁ receptor response to leukotriene D₄ (LTD₄). For further discussion, see [20]. Reported to antagonize CysLT₁ receptor signalling in vivo and in vitro [75].

GPR18 Show summary »« Hide summary More detailed page

Nomenclature

GPR18

Previous and unofficial names

GPR18, G-protein coupled receptor 18, NAGly receptor, GPCRW, N-arachidonoyol glycine receptor, Gpr18_predicted, LOC306191, LOC679957, MGC156838, G protein-coupled receptor 18, G protein-coupled receptor 18 (predicted), similar to G protein-coupled receptor 18

Genes

GPR18 (Hs), Gpr18 (Mm), Gpr18 (Rn)

Ensembl ID

ENSG00000125245 (Hs), ENSMUSG00000050350 (Mm), ENSRNOG00000012628 (Rn)

UniProtKB AC

Q14330 (Hs), Q8K1Z6 (Mm), A1A5S3 (Rn)

Principal transduction

G_i/o [55]

Endogenous agonists
(pK_i)

N-arachidonoylglycine [55]

Comment

The pairing of N-arachidonoylglycine with GPR18 was not replicated in two studies based on β-arrestin assays [110,128].

GPR19 Show summary »« Hide summary More detailed page

GPR20 Show summary »« Hide summary More detailed page

Nomenclature	GPR20
Previous and unofficial names	Gpcr5-1, P2Y4, GPR20, G-protein coupled receptor 20, G protein-coupled receptor 20, G protein-coupled receptor 5-1, A430106B11Rik
Genes	GPR20 (Hs), Gpr20 (Mm), Gpr20 (Rn)
Ensembl ID	ENSG00000204882 (Hs), ENSMUSG00000045281 (Mm), ENSRNOG00000007795 (Rn)
UniProtKB AC	Q99678 (Hs), Q8BYC4 (Mm), O35797 (Rn)
Principal transduction	-
Comment	Reported to inhibit adenylyl cyclase constitutively through G_i/o [34]. GPR20 deficient mice exhibit hyperactivity characterised by increased total distance travelled in an open field test [9].

GPR21 Show summary »« Hide summary More detailed page

Nomenclature	GPR21
Previous and unofficial names	LOC689917, G protein-coupled receptor 21, probable G-protein coupled receptor 21, similar to G protein-coupled receptor 21, C230004C13Rik
Genes	GPR21 (Hs), Gpr21 (Mm), Gpr21 (Rn)
Ensembl ID	ENSG00000188394 (Hs), ENSMUSG00000053164 (Mm), ENSRNOG00000042269 (Rn)
UniProtKB AC	Q99679 (Hs), Q8BX79 (Mm)
Principal transduction	G_q/11
Comment	Gpr21 knockout mice were resistant to diet-induced obesity, exhibiting an increase in glucose tolerance and insulin sensitivity and a modest lean phenotype [90].

GPR22 Show summary »« Hide summary More detailed page

Nomenclature	GPR22
Previous and unofficial names	Gpr22_predicted, LOC298944, G protein-coupled receptor 22, G protein-coupled receptor 22 (predicted), probable G-protein coupled receptor 22, 2900068K05Rik, AW061316
Genes	GPR22 (Hs), Gpr22 (Mm), Gpr22 (Rn)
Ensembl ID	ENSG00000172209 (Hs), ENSMUSG00000044067 (Mm), ENSRNOG00000008423 (Rn)
UniProtKB AC	Q99680 (Hs), Q8BZL4 (Mm), D4A3U0 (Rn)
Principal transduction	G_i/o
Comment	Gene disruption results in increased severity of functional decompensation following aortic banding [1]. Identified as a susceptibility locus for osteoarthritis [27,52,118].

GPR25 Show summary »« Hide summary More detailed page

Nomenclature	GPR25
Previous and unofficial names	GPR25, G-protein coupled receptor 25, probable G-protein coupled receptor 25, Gpr25_predicted, LOC363993, G protein-coupled receptor 25, G protein-coupled receptor 25 (predicted), LOC383563, Gm1300
Genes	GPR25 (Hs), Gpr25 (Mm), Gpr25 (Rn)
Ensembl ID	ENSG00000170128 (Hs), ENSMUSG00000052759 (Mm), ENSRNOG00000008603 (Rn)
UniProtKB AC	O00155 (Hs), P0C5I1 (Mm)
Principal transduction	-

GPR26 Show summary »« Hide summary More detailed page

Nomenclature	GPR26
Previous and unofficial names	GPR26, G-protein coupled receptor 26, G protein-coupled receptor 26, probable G-protein coupled receptor 26, 9630036A11Rik
Genes	GPR26 (Hs), Gpr26 (Mm), Gpr26 (Rn)
Ensembl ID	ENSG00000154478 (Hs), ENSMUSG00000040125 (Mm), ENSRNOG00000047057 (Rn)
UniProtKB AC	Q8NDV2 (Hs), Q8BZA7 (Mm), Q9QXI3 (Rn)
Principal transduction	G_s
Comment	Has been reported to activate adenylyl cyclase constitutively through G_s [45]. Gpr26 knockout mice show increased levels of anxiety and depression-like behaviours [131].

GPR27 Show summary »« Hide summary More detailed page

Nomenclature	GPR27
Previous and unofficial names	super conserved receptor expressed in brain 1, SREB1, super-conserved receptor expressed in brain 1, GPR27, G-protein coupled receptor 27, probable G-protein coupled receptor 27, G protein-coupled receptor 27
Genes	GPR27 (Hs), Gpr27 (Mm), Gpr27 (Rn)
Ensembl ID	ENSG00000170837 (Hs), ENSMUSG00000072875 (Mm), ENSRNOG00000010880 (Rn)
UniProtKB AC	Q9NS67 (Hs), O54897 (Mm), Q9JJH3 (Rn)
Principal transduction	G_q/G₁₁
Comment	Knockdown of Gpr27 reduces endogenous mouse insulin promotor activity and glucose stimulated insulin secretion [60].

GPR31 Show summary »« Hide summary More detailed page

Nomenclature

GPR31

Previous and unofficial names

bA517H2.2, GPR31, G protein-coupled receptor 31, probable G-protein coupled receptor 31, HETER1, 12-HETER, hydroxyeicosatetraenoic (HETE) acid receptor 1, 12-(S)-HETE acid receptor, Gpr31_predicted, LOC292310, G protein-coupled receptor 31 (predicted), G protein-coupled receptor 31, D17Leh66c region (pseudogene)

Genes

GPR31 (Hs), Gpr31c (Mm), Gpr31 (Rn)

Ensembl ID

ENSG00000120436 (Hs), ENSMUSG00000071311 (Mm), ENSRNOG00000039255 (Rn)

UniProtKB AC

O00270 (Hs), F8VQN3 (Mm)

Principal transduction

Endogenous agonists
(pK_i)

12S-HETE (Selective) (pEC₅₀ 9.55 - Mouse) [31]

GPR32 Show summary »« Hide summary More detailed page

Nomenclature

GPR32

Previous and unofficial names

GPR32, G-protein coupled receptor 32, probable G-protein coupled receptor 32, RvD1, RVDR1, resolvin D1 receptor

Genes

GPR32 (Hs)

Ensembl ID

ENSG00000142511 (Hs)

UniProtKB AC

O75388 (Hs)

Principal transduction

Not yet established

Rank order of potency

resolvin D1 > LXA₄

Endogenous agonists
(pK_i)

resolvin D1 (Selective) (pEC₅₀ 11.06) [59]

LXA₄ (Selective) (pEC₅₀ 9.7) [59]

Radioligands
(K_d)

[³H]resolvin D1 (Agonist) (2x10^-10 M) [59]

Comment

resolvin D1 has been demonstrated to activate GPR32 in two publications [17,59]. The pairing was not replicated in a recent study based on β-arrestin recruitment [110]. GPR32 is a pseudogene in mice and rats.

GPR33 Show summary »« Hide summary More detailed page

Nomenclature	GPR33
Previous and unofficial names	G protein-coupled receptor 33, pseudogene, G protein-coupled receptor 33 pseudogene, G protein-coupled receptor 33, Gpr33, Gpr33_predicted, LOC299007, G protein-coupled receptor 33 (predicted), probable G-protein coupled receptor 33
Genes	GPR33 (Hs), Gpr33 (Mm), Gpr33 (Rn)
Ensembl ID	ENSG00000214943 (Hs), ENSMUSG00000035148 (Mm), ENSRNOG00000038990 (Rn)
UniProtKB AC	Q49SQ1 (Hs), O88416 (Mm), Q49SP8 (Rn)
Principal transduction	G_i/G_o
Comment	GPR33 is a pseudogene in most individuals, containing a premature stop codon within the coding sequence of the second intracellular loop [103].

GPR34 Show summary »« Hide summary More detailed page

Nomenclature

GPR34

Previous and unofficial names

GPR34, GPR34_predicted, G protein-coupled receptor 34, G-protein-coupled receptor GPR34, G-protein-coupled receptor GPR34 (predicted), probable G-protein coupled receptor 34

Genes

GPR34 (Hs), Gpr34 (Mm), Gpr34 (Rn)

Ensembl ID

ENSG00000171659 (Hs), ENSMUSG00000040229 (Mm), ENSRNOG00000039759 (Rn)

UniProtKB AC

Q9UPC5 (Hs), Q9R1K6 (Mm), Q6XCE7 (Rn)

Principal transduction

G_i/G_o

Endogenous agonists
(pK_i)

lysophosphatidylserine (Selective) (pEC₅₀ 6.57 – 6.89) [54,111]

Comment

Lysophosphatidylserine has been reported to be a ligand of GPR34 in several publications, but the pairing was not replicated in a recent study based on β-arrestin recruitment [110]. Fails to respond to a variety of lipid-derived agents [128]. Gene disruption results in an enhanced immune response [68].

GPR35 Show summary »« Hide summary More detailed page

Nomenclature

GPR35

Previous and unofficial names

GPR35, G-protein coupled receptor 35, G protein-coupled receptor 35, Kynurenic acid receptor, KYNA receptor, G-protein coupled receptor 3, Gpr35_predicted, LOC367315, G protein-coupled receptor 35 (predicted)

Genes

GPR35 (Hs), Gpr35 (Mm), Gpr35 (Rn)

Ensembl ID

ENSG00000178623 (Hs), ENSMUSG00000026271 (Mm), ENSRNOG00000024030 (Rn)

UniProtKB AC

Q9HC97 (Hs), Q9ES90 (Mm), Q33BM1 (Rn)

Principal transduction

Endogenous agonists
(pK_i)

2-oleoyl-LPA (pEC₅₀ 7.3 – 7.52) [88]

kynurenic acid (pEC₅₀ 3.9 – 4.41) [110,120]

Comment

Several studies have shown that kynurenic acid is an agonist of GPR35 but it remains controversial whether the proposed endogenous ligand reaches sufficient tissue concentrations to activate the receptor [61]. 2-oleoyl-LPA has also been proposed as an endogenous ligand [88] but these results were not replicated in in a recent β-arrestin assay [110]. The phosphodiesterase inhibitor zaprinast [115] has become widely used as a surrogate agonist to investigate GPR35 pharmacology and signaliing [115]. GPR35 is also activated by the pharmaceutical adjunct pamoic acid [133].

GPR37 Show summary »« Hide summary More detailed page

Nomenclature

GPR37

Previous and unofficial names

ETBR-LP-1, EDNRBL, Endothelin B receptor-like protein 1, PAELR, EDNRLB, GPR37, G protein-coupled receptor 37 (endothelin receptor type B-like), hET(B)R-LP, probable G-protein coupled receptor 37, endothelin receptor type B-like, Parkin-associated endothelin receptor-like receptor, MGC105347, G protein-coupled receptor 37, G-protein coupled receptor CNS1, Pael-R, parkin-associated endothelin B-like receptor, AI848630

Genes

GPR37 (Hs), Gpr37 (Mm), Gpr37 (Rn)

Ensembl ID

ENSG00000170775 (Hs), ENSMUSG00000039904 (Mm), ENSRNOG00000002524 (Rn)

UniProtKB AC

O15354 (Hs), Q9QY42 (Mm), Q9QYC6 (Rn)

Principal transduction

G_i/G_o

Selective agonists
(pK_i)

neuropeptide head activator (pEC₅₀ 7.96 – 8.48) [97]

Comment

Reported to associate and regulate the dopamine transporter [80] and to be a substrate for parkin [78]. Gene disruption results in altered striatal signalling [79].

GPR37L1 Show summary »« Hide summary More detailed page

Nomenclature	GPR37L1
Previous and unofficial names	G-protein coupled receptor 37-like 1, D0Kist8, CAG-18, ETBR-LP-2, GPR37L1, ET(B)R-LP-2, ETBRLP2, G protein-coupled receptor 37 like 1, endothelin B receptor-like protein 2, G-protein coupled receptor CNS2, AW047233
Genes	GPR37L1 (Hs), Gpr37l1 (Mm), Gpr37l1 (Rn)
Ensembl ID	ENSG00000170075 (Hs), ENSMUSG00000026424 (Mm), ENSRNOG00000006237 (Rn)
UniProtKB AC	O60883 (Hs), Q99JG2 (Mm), Q9QYC5 (Rn)
Principal transduction	G_i/G_o

GPR39 Show summary »« Hide summary More detailed page

Nomenclature

GPR39

Previous and unofficial names

MGC149541, GPR39, G-protein coupled receptor 39, Gpr39_predicted, LOC288995, G protein-coupled receptor 39, G protein-coupled receptor 39 (predicted), 4933415E13Rik

Genes

GPR39 (Hs), Gpr39 (Mm), Gpr39 (Rn)

Ensembl ID

ENSG00000183840 (Hs), ENSMUSG00000026343 (Mm), ENSRNOG00000021586 (Rn)

UniProtKB AC

O43194 (Hs), Q5U431 (Mm)

Principal transduction

G_q/G₁₁

Endogenous agonists
(pK_i)

Zn²⁺ [38]

Comment

Zn²⁺ has been reported to be a potent and efficacious agonist of human, mouse and rat GPR39 [127]. obestatin (GHRL, Q9UBU3), a fragment from the ghrelin precursor, was reported initially as an endogenous ligand, but subsequent studies failed to reproduce these findings. Has been reported to be down-regulated in adipose tissue in obesity-related diabetes [12]. Gene disruption results in obesity and altered adipocyte metabolism [94].

GPR42 Show summary »« Hide summary More detailed page

Nomenclature	GPR42
Previous and unofficial names	FFAR1L, GPR41L, GPR42P, FFAR3L, G protein-coupled receptor 42 pseudogene
Genes	GPR42 (Hs)
Ensembl ID	ENSG00000126251 (Hs)
UniProtKB AC	O15529 (Hs)
Principal transduction	-

GPR45 Show summary »« Hide summary More detailed page

Nomenclature	GPR45
Previous and unofficial names	PSP24-1, PSP24-alpha, PSP24A, PSP24, GPR45, G-protein coupled receptor 45, high-affinity lysophosphatidic acid receptor, probable G-protein coupled receptor 45, PSP24(ALPHA), Gpr45_predicted, LOC301372, G protein-coupled receptor 45, G protein-coupled receptor 45 (predicted), PSP24alpha, 9230112G11Rik, AW046772
Genes	GPR45 (Hs), Gpr45 (Mm), Gpr45 (Rn)
Ensembl ID	ENSG00000135973 (Hs), ENSMUSG00000041907 (Mm), ENSRNOG00000016446 (Rn)
UniProtKB AC	Q9Y5Y3 (Hs), Q9EQQ4 (Mm)
Principal transduction	-

GPR50 Show summary »« Hide summary More detailed page

Nomenclature	GPR50
Previous and unofficial names	MGC125342, MTNRL, H9, GPR50, G-protein coupled receptor 50, Mel1c, melatonin-related receptor
Genes	GPR50 (Hs), Gpr50 (Mm), Gpr50 (Rn)
Ensembl ID	ENSG00000102195 (Hs), ENSMUSG00000056380 (Mm), ENSRNOG00000011335 (Rn)
UniProtKB AC	Q13585 (Hs), O88495 (Mm), Q62953 (Rn)
Principal transduction	-
Comment	GPR50 is structurally related to MT₁ and MT₂ melatonin receptors, with which it heterodimerises constitutively and specifically [66]. GPR50 knockout mice display abnormal thermoregulation and are much more likely than wild-type mice to enter fasting-induced torpor [4].

GPR52 Show summary »« Hide summary More detailed page

Nomenclature	GPR52
Previous and unofficial names	MGC111751, EG620246, GPR52, G-protein coupled receptor 52, probable G-protein coupled receptor 52, LOC680192, G protein-coupled receptor 52, similar to Probable G-protein coupled receptor 52
Genes	GPR52 (Hs), Gpr52 (Mm), Gpr52 (Rn)
Ensembl ID	ENSG00000203737 (Hs)
UniProtKB AC	Q9Y2T5 (Hs), P0C5J4 (Mm)
Principal transduction	-

GPR55 Show summary »« Hide summary More detailed page

GPR61 Show summary »« Hide summary More detailed page

Nomenclature	GPR61
Previous and unofficial names	GPCR3, BALGR, GPR61, G protein-coupled receptor 61, Biogenic amine receptor-like G-protein coupled receptor, probable G-protein coupled receptor 61, biogenic amine receptor-like GPCR, Gpr61_predicted, LOC310780, G protein-coupled receptor 61 (predicted)
Genes	GPR61 (Hs), Gpr61 (Mm), Gpr61 (Rn)
Ensembl ID	ENSG00000156097 (Hs), ENSMUSG00000046793 (Mm), ENSRNOG00000019738 (Rn)
UniProtKB AC	Q9BZJ8 (Hs), Q8C010 (Mm)
Principal transduction	G_s
Comment	GPR61 deficient mice exhibit obesity associated with hyperphagia [83]. Although no endogenous ligands have been identified, 5-(nonyloxy)tryptamine has been reported to be a low affinity inverse agonist [114].

GPR62 Show summary »« Hide summary More detailed page

Nomenclature	GPR62
Previous and unofficial names	KPG_005, MGC26943, GPCR8, LOC501049, RGD1560166_predicted, similar to Probable G-protein coupled receptor 62 (hGPCR8), similar to Probable G-protein coupled receptor 62 (hGPCR8) (predicted), 4933402E03Rik
Genes	GPR62 (Hs), Gpr62 (Mm), Gpr62 (Rn)
Ensembl ID	ENSG00000180929 (Hs), ENSMUSG00000091735 (Mm), ENSRNOG00000022567 (Rn)
UniProtKB AC	Q9BZJ7 (Hs), Q80UC6 (Mm), D4A2B1 (Rn)
Principal transduction	-

GPR63 Show summary »« Hide summary More detailed page

Nomenclature	GPR63
Previous and unofficial names	PSP24(beta), PSP24-2, PSP24B, Gpr63_predicted, LOC297952, G protein-coupled receptor 63, G protein-coupled receptor 63 (predicted), probable G-protein coupled receptor 63, PSP24beta
Genes	GPR63 (Hs), Gpr63 (Mm), Gpr63 (Rn)
Ensembl ID	ENSG00000112218 (Hs), ENSMUSG00000040372 (Mm), ENSRNOG00000007675 (Rn)
UniProtKB AC	Q9BZJ6 (Hs), Q9EQQ3 (Mm)
Principal transduction	-
Comment	sphingosine 1-phosphate and dioleoylphosphatidic acid have been reported to be low affinity agonists for GPR63 [85] but this finding was not replicated in a β-arrestin-based assay [128].

GPR65 Show summary »« Hide summary More detailed page

Nomenclature	GPR65
Previous and unofficial names	Psychosine receptor, T cell death-associated protein 8, Dig1, Gpcr25, TDAG8, GPR65, G-protein coupled receptor 65, hTDAG8, Gpr65_predicted, LOC299242, G-protein coupled receptor 65 (predicted), T cell death associated protein 8, rCG_20955
Genes	GPR65 (Hs), Gpr65 (Mm), Gpr65 (Rn)
Ensembl ID	ENSG00000140030 (Hs), ENSMUSG00000021886 (Mm), ENSRNOG00000003806 (Rn)
UniProtKB AC	Q8IYL9 (Hs), Q61038 (Mm)
Principal transduction	G_s
Endogenous ligand	Protons
Comment	GPR4, GPR65, GPR68 and GPR132 are now thought to function as proton-sensing receptors detecting acidic pH [20,105]. Reported to activate adenylyl cyclase; gene disruption leads to reduced eosinophlia in models of allergic airway disease [58].

GPR68 Show summary »« Hide summary More detailed page

Nomenclature	GPR68
Previous and unofficial names	Ovarian cancer G-protein coupled receptor 1, OGR-1, GPR12A, MGC111379, sphingosylphosphorylcholine receptor, OGR1, Gpr68_predicted, LOC314386, G protein-coupled receptor 68, G protein-coupled receptor 68 (predicted), BB131428
Genes	GPR68 (Hs), Gpr68 (Mm), Gpr68 (Rn)
Ensembl ID	ENSG00000119714 (Hs), ENSMUSG00000047415 (Mm), ENSRNOG00000027863 (Rn)
UniProtKB AC	Q15743 (Hs), Q8BFQ3 (Mm)
Principal transduction	-
Endogenous ligand	Protons
Comment	Gpr68 was previously identified as a receptor for sphingosylphosphorylcholine (SPC) [124], but the original publication has been retracted [125]. GPR4, GPR65, GPR68 and GPR132 are now thought to function as protein-sensing receptors detecting acidic pH [20,105]. A family of 3,5-disubstituted isoxazoles were identified as agonists of GPR68 [101].

GPR75 Show summary »« Hide summary More detailed page

Nomenclature	GPR75
Previous and unofficial names	GPR-chr2, WI-31133, WI31133, GPR75, G-protein coupled receptor 75, GPRchr2, probable G-protein coupled receptor 75, LOC498434, RGD1566385, RGD1566385_predicted, G protein-coupled receptor 75, G protein-coupled receptor GPR75, similar to G protein-coupled receptor GPR75, similar to G protein-coupled receptor GPR75 (predicted)
Genes	GPR75 (Hs), Gpr75 (Mm), Gpr75 (Rn)
Ensembl ID	ENSG00000119737 (Hs), ENSMUSG00000043999 (Mm), ENSRNOG00000022176 (Rn)
UniProtKB AC	O95800 (Hs), Q6X632 (Mm), D3Z826 (Rn)
Principal transduction	G_q/G₁₁
Comment	CCL5 (CCL5, P13501) was reported to be an agonist of GPR75 [42], but the pairing could not be repeated in a recent β-arrestin assay [110].

GPR78 Show summary »« Hide summary More detailed page

Nomenclature	GPR78
Previous and unofficial names	GPR78, G-protein coupled receptor 78
Genes	GPR78 (Hs)
Ensembl ID	ENSG00000155269 (Hs)
UniProtKB AC	Q96P69 (Hs)
Principal transduction	G_s
Comment	GPR78 has been reported to be constitutively active, coupled to elevated cAMP production [45].

GPR79 Show summary »« Hide summary More detailed page

Nomenclature	GPR79
Previous and unofficial names	G protein-coupled receptor 79 pseudogene, GPR79, GPR79P
Genes	GPR79 (Hs)
Ensembl ID	ENSG00000232374 (Hs)
UniProtKB AC	-
Principal transduction	-

GPR82 Show summary »« Hide summary More detailed page

Nomenclature	GPR82
Previous and unofficial names	-
Genes	GPR82 (Hs), Gpr82 (Mm)
Ensembl ID	ENSG00000171657 (Hs), ENSMUSG00000047678 (Mm)
UniProtKB AC	Q96P67 (Hs), Q8BZR0 (Mm)
Principal transduction	-
Comment	Mice with Gpr82 knockout have a lower body weight and body fat content associated with reduced food intake, decreased serum triglyceride levels, higher insulin sensitivity and glucose tolerance [26].

GPR83 Show summary »« Hide summary More detailed page

Nomenclature	GPR83
Previous and unofficial names	GPR72, KIAA1540, glucocorticoid-induced receptor, GIR, RP105, RP39, RP82, GPR83, G-protein coupled receptor 83, G protein-coupled receptor 83, G-protein coupled receptor 72, glucocorticoid induced receptor, probable G-protein coupled receptor, JP05 [10], G protein-coupled receptor 72, probable G-protein coupled receptor 83, AW045253
Genes	GPR83 (Hs), Gpr83 (Mm), Gpr83 (Rn)
Ensembl ID	ENSG00000123901 (Hs), ENSMUSG00000031932 (Mm), ENSRNOG00000030318 (Rn)
UniProtKB AC	Q9NYM4 (Hs), P30731 (Mm)
Principal transduction	-
Comment	One isoform has been implicated in the induction of CD4(+)CD25(+) regulatory T cells (Tregs) during inflammatory immune responses [33].

GPR84 Show summary »« Hide summary More detailed page

Nomenclature

GPR84

Previous and unofficial names

EX33, GPR84, G-protein coupled receptor 84, G protein-coupled receptor 84, Inflammation-related G-protein coupled receptor EX33, GPCR4, LOC688730, similar to G protein-coupled receptor 84

Genes

GPR84 (Hs), Gpr84 (Mm), Gpr84 (Rn)

Ensembl ID

ENSG00000139572 (Hs), ENSMUSG00000063234 (Mm), ENSRNOG00000036834 (Rn)

UniProtKB AC

Q9NQS5 (Hs), Q8CIM5 (Mm)

Principal transduction

G_i/G_o

Selective agonists
(pK_i)

decanoic acid (pEC₅₀ 5.0 – 5.4) [110,121]

undecanoic acid (pEC₅₀ 5.1) [121]

lauric acid (pEC₅₀ 5.05) [121]

Comment

Medium chain free fatty acids with carbon chain lengths of 9-14 activate GPR84 [112,121]. A surrogate ligand for GPR84, 6-n-octylaminouracil has also been proposed [112].

GPR85 Show summary »« Hide summary More detailed page

Nomenclature	GPR85
Previous and unofficial names	Super Conserved Receptor Expressed in Brain 2, Srep2, MGC105281, SREB2, GPR85, G protein-coupled receptor 85, Super conserved receptor expressed in brain 2, seven transmembrane helix receptor, probable G-protein coupled receptor 85, SREB, PKrCx1, 2900026B03Rik, rgpr85
Genes	GPR85 (Hs), Gpr85 (Mm), Gpr85 (Rn)
Ensembl ID	ENSG00000164604 (Hs), ENSMUSG00000048216 (Mm), ENSRNOG00000024636 (Rn)
UniProtKB AC	P60893 (Hs), P60894 (Mm), P60895 (Rn)
Principal transduction	-
Comment	Proposed to regulate of hippocampal adult neurogenesis and neurogenesis-dependent learning and memory [16].

GPR87 Show summary »« Hide summary More detailed page

Nomenclature

GPR87

Previous and unofficial names

FKSG78, KPG_002, MGC131898, GPR95, Gpr87_predicted, LOC310443, G protein-coupled receptor 87, G protein-coupled receptor 87 (predicted), G-protein coupled receptor 87

Genes

GPR87 (Hs), Gpr87 (Mm), Gpr87 (Rn)

Ensembl ID

ENSG00000138271 (Hs), ENSMUSG00000051431 (Mm), ENSRNOG00000013894 (Rn)

UniProtKB AC

Q9BY21 (Hs), Q99MT7 (Mm)

Principal transduction

Endogenous agonists
(pK_i)

LPA (pEC₅₀ 7.44) [82,113]

GPR88 Show summary »« Hide summary More detailed page

Nomenclature	GPR88
Previous and unofficial names	Strg, STRG, GPR88, G-protein coupled receptor 88, probable G-protein coupled receptor 88, G protein coupled receptor 88, G protein-coupled receptor 88, striatum-specific G-protein coupled receptor, AW061286
Genes	GPR88 (Hs), Gpr88 (Mm), Gpr88 (Rn)
Ensembl ID	ENSG00000181656 (Hs), ENSMUSG00000068696 (Mm), ENSRNOG00000026953 (Rn)
UniProtKB AC	Q9GZN0 (Hs), Q9EPB7 (Mm), Q9ESP4 (Rn)
Principal transduction	-
Comment	Gene disruption results in altered striatal signalling [72].

GPR101 Show summary »« Hide summary More detailed page

Nomenclature	GPR101
Previous and unofficial names	GPCR6, RGD1564196, GPR101, G-protein coupled receptor 101, probable G-protein coupled receptor 101, Gpr101_predicted, LOC317608, RGD1564196_predicted, G protein-coupled receptor 101, G protein-coupled receptor 101 (predicted), similar to G protein-coupled receptor 101, similar to G protein-coupled receptor 101 (predicted), Gm365, LOC245424
Genes	GPR101 (Hs), Gpr101 (Mm), Gpr101 (Rn)
Ensembl ID	ENSG00000165370 (Hs), ENSMUSG00000036357 (Mm), ENSRNOG00000027658 (Rn)
UniProtKB AC	Q96P66 (Hs), Q80T62 (Mm), D4ABK4 (Rn)
Principal transduction	G_s

GPR119 Show summary »« Hide summary More detailed page

GPR132 Show summary »« Hide summary More detailed page

Nomenclature	GPR132
Previous and unofficial names	MGC99642, G2A, GPR132, G-protein coupled receptor 132, G2 accumulation protein, G protein-coupled receptor G2A, probable G-protein coupled receptor 132, G2 accumulation, Gpr132_predicted, LOC314480, G protein-coupled receptor 132, G protein-coupled receptor 132 (predicted)
Genes	GPR132 (Hs), Gpr132 (Mm), Gpr132 (Rn)
Ensembl ID	ENSG00000183484 (Hs), ENSMUSG00000021298 (Mm), ENSRNOG00000013914 (Rn)
UniProtKB AC	Q9UNW8 (Hs), Q9Z282 (Mm), D3ZIH1 (Rn)
Principal transduction	G_s
Endogenous ligand	Protons
Comment	GPR4, GPR65, GPR68 and GPR132 are now thought to function as protein-sensing receptors detecting acidic pH [20,105]. Reported to respond to lysophosphatidylcholine [46], but later retracted [123].

GPR135 Show summary »« Hide summary More detailed page

Nomenclature	GPR135
Previous and unofficial names	PAFR, HUMNPIIY20, GPR135, G-protein coupled receptor 135, probable G-protein coupled receptor 135, G protein-coupled receptor 135
Genes	GPR135 (Hs), Gpr135 (Mm), Gpr135 (Rn)
Ensembl ID	ENSG00000181619 (Hs), ENSMUSG00000043398 (Mm), ENSRNOG00000004499 (Rn)
UniProtKB AC	Q8IZ08 (Hs), Q7TQP2 (Mm), Q7TQN7 (Rn)
Principal transduction	-

GPR139 Show summary »« Hide summary More detailed page

Nomenclature	GPR139
Previous and unofficial names	GPRg1, PGR3, GPR139, G-protein coupled receptor 139, G(q)-coupled orphan receptor GPRg1, G-protein-coupled receptor PGR3, probable G-protein coupled receptor 139, GPRG1, Gpr139_predicted, LOC293545, G protein-coupled receptor 139, G protein-coupled receptor 139 (predicted), Gm495, LOC209776
Genes	GPR139 (Hs), Gpr139 (Mm), Gpr139 (Rn)
Ensembl ID	ENSG00000180269 (Hs), ENSMUSG00000066197 (Mm), ENSRNOG00000023863 (Rn)
UniProtKB AC	Q6DWJ6 (Hs), Q80UC8 (Mm), P0C0W8 (Rn)
Principal transduction	G_q/G₁₁

GPR141 Show summary »« Hide summary More detailed page

Nomenclature	GPR141
Previous and unofficial names	PGR13, GPR141, G-protein coupled receptor 141, G-protein coupled receptor PGR13, probable G-protein coupled receptor 141, axor115, G protein-coupled receptor 141
Genes	GPR141 (Hs), Gpr141 (Mm), Gpr141 (Rn)
Ensembl ID	ENSG00000187037 (Hs), ENSMUSG00000053101 (Mm), ENSRNOG00000042801 (Rn)
UniProtKB AC	Q7Z602 (Hs), Q7TQP0 (Mm), Q7TQN5 (Rn)
Principal transduction	-

GPR142 Show summary »« Hide summary More detailed page

Nomenclature	GPR142
Previous and unofficial names	PGR2, KIF19, GPR142, G-protein coupled receptor 142, G-protein coupled receptor PGR2, probable G-protein coupled receptor 142, AXOR103, LOC501735, RGD1559926, RGD1559926_predicted, G protein-coupled receptor 142, similar to G protein-coupled receptor 142, similar to G protein-coupled receptor 142 (predicted)
Genes	GPR142 (Hs), Gpr142 (Mm), Gpr142 (Rn)
Ensembl ID	ENSG00000196169 (Hs), ENSMUSG00000034677 (Mm), ENSRNOG00000024446 (Rn)
UniProtKB AC	Q7Z601 (Hs), Q7TQN9 (Mm), F1LWD8 (Rn)
Principal transduction	-

GPR146 Show summary »« Hide summary More detailed page

Nomenclature	GPR146
Previous and unofficial names	PGR8, GPR146, G-protein coupled receptor 146, G-protein coupled receptor PGR8, AXOR120, LOC498153, RGD1560731, RGD1560731_predicted, G protein-coupled receptor 146, probable G-protein coupled receptor 146, similar to G protein-coupled receptor 146, similar to G protein-coupled receptor 146 (predicted), BC003323
Genes	GPR146 (Hs), Gpr146 (Mm), Gpr146 (Rn)
Ensembl ID	ENSG00000164849 (Hs), ENSMUSG00000044197 (Mm), ENSRNOG00000001288 (Rn)
UniProtKB AC	Q96CH1 (Hs), Q99LE2 (Mm)
Principal transduction	-
Comment	Yosten et al. demonstrated inhibition of proinsulin C-peptide (INS, P01308)-induced stimulation of cFos expression folllowing knockdown of GPR146 in KATOIII cells, suggesting proinsulin C-peptide as an endogenous ligand of the receptor [130].

GPR148 Show summary »« Hide summary More detailed page

Nomenclature	GPR148
Previous and unofficial names	BTR, PGR6, brain and testis restricted GPCR, GPR148, G-protein coupled receptor 148, G-protein coupled receptor PGR6, probable G-protein coupled receptor 148
Genes	GPR148 (Hs)
Ensembl ID	ENSG00000173302 (Hs)
UniProtKB AC	Q8TDV2 (Hs)
Principal transduction	-

GPR149 Show summary »« Hide summary More detailed page

Nomenclature	GPR149
Previous and unofficial names	PGR10, IEDA, GPR149, G-protein coupled receptor 149, G-protein coupled receptor PGR10, probable G-protein coupled receptor 149, R35, G protein-coupled receptor 149, induced early in differentiating astrocytes gene protein, orphan seven transmembrane receptor, 9630018L10Rik
Genes	GPR149 (Hs), Gpr149 (Mm), Gpr149 (Rn)
Ensembl ID	ENSG00000174948 (Hs), ENSMUSG00000043441 (Mm), ENSRNOG00000014793 (Rn)
UniProtKB AC	Q86SP6 (Hs), Q3UVY1 (Mm), Q924Y8 (Rn)
Principal transduction	-
Comment	Gpr149 knockout mice displayed increased fertility and enhanced ovulation, with increased levels of FSH receptor and cyclin D2 mRNA levels [24].

GPR150 Show summary »« Hide summary More detailed page

Nomenclature	GPR150
Previous and unofficial names	PGR11, GPR150, G-protein coupled receptor 150, seven transmembrane helix receptor, probable G-protein coupled receptor 150, AXOR70, LOC499486, RGD1564729, RGD1564729_predicted, G protein-coupled receptor 150, similar to G protein-coupled receptor 150, similar to G protein-coupled receptor 150 (predicted), C030001A19Rik
Genes	GPR150 (Hs), Gpr150 (Mm), Gpr150 (Rn)
Ensembl ID	ENSG00000178015 (Hs), ENSMUSG00000045509 (Mm), ENSRNOG00000026944 (Rn)
UniProtKB AC	Q8NGU9 (Hs), Q8BL07 (Mm)
Principal transduction	-

GPR151 Show summary »« Hide summary More detailed page

Nomenclature	GPR151
Previous and unofficial names	GALRL, galanin receptor 4, PGR7, GALR4, GPCR-2037, GPR151, G-protein coupled receptor 151, G protein-coupled receptor 151, G-protein coupled receptor PGR7, putative G-protein coupled receptor, probable G-protein coupled receptor 151, galanin receptor-like GPCR, AXOR40, nGPCR-2037, putative G protein-coupled receptor nGPCR-2037, C130082O03Rik
Genes	GPR151 (Hs), Gpr151 (Mm), Gpr151 (Rn)
Ensembl ID	ENSG00000173250 (Hs), ENSMUSG00000042816 (Mm), ENSRNOG00000027103 (Rn)
UniProtKB AC	Q8TDV0 (Hs), Q7TSN6 (Mm), Q7TSN5 (Rn)
Principal transduction	-
Comment	GPR151 responded to galanin with an EC₅₀ value of 2 µM, suggesting that the endogenous ligand shares structural features with galanin (GAL, P22466) [39].

GPR152 Show summary »« Hide summary More detailed page

Nomenclature	GPR152
Previous and unofficial names	PGR1, MGC148162, PGR5, GPR152, G-protein coupled receptor 152, G protein-coupled receptor 152, probable G-protein coupled receptor 152, G-protein coupled receptor PGR5, LOC688884, similar to putative G-protein coupled receptor, LOC269053, A930009H15Rik, Gm673
Genes	GPR152 (Hs), Gpr152 (Mm), Gpr152 (Rn)
Ensembl ID	ENSG00000175514 (Hs), ENSMUSG00000044724 (Mm)
UniProtKB AC	Q8TDT2 (Hs), Q8BXS7 (Mm)
Principal transduction	-

GPR153 Show summary »« Hide summary More detailed page

Nomenclature	GPR153
Previous and unofficial names	DKFZp762B2210, PGR1, G protein-coupled receptor 153, probable G-protein coupled receptor 153, 1110065N12Rik, AI449320
Genes	GPR153 (Hs), Gpr153 (Mm), Gpr153 (Rn)
Ensembl ID	ENSG00000158292 (Hs), ENSMUSG00000042804 (Mm)
UniProtKB AC	Q6NV75 (Hs), Q8K0Z9 (Mm), Q3KR68 (Rn)
Principal transduction	-

GPR160 Show summary »« Hide summary More detailed page

GPR161 Show summary »« Hide summary More detailed page

Nomenclature	GPR161
Previous and unofficial names	FLJ33952, RE2, GPR161, G-protein coupled receptor 161, G-protein coupled receptor RE2, LOC289180, RGD1563245, RGD1563245_predicted, G protein-coupled receptor 161, similar to G protein-coupled receptor 161, similar to G protein-coupled receptor 161 (predicted), LOC240888, vl, Gm208Gpr
Genes	GPR161 (Hs), Gpr161 (Mm), Gpr161 (Rn)
Ensembl ID	ENSG00000143147 (Hs), ENSMUSG00000040836 (Mm), ENSRNOG00000003073 (Rn)
UniProtKB AC	Q8N6U8 (Hs), B2RPY5 (Mm), F1M5Q2 (Rn)
Principal transduction	-
Comment	A C-terminal truncation (deletion) mutation in Gpr61 causes congenital cataracts and neural tube defects in the vacuolated lens (vl) mouse mutant [81]. The mutated receptor is associated with cataract, spina bifida and white belly spot phenotypes in mice [57]. Gene disruption is associated with a failure of asymmetric embryonic development in zebrafish [65].

GPR162 Show summary »« Hide summary More detailed page

Nomenclature	GPR162
Previous and unofficial names	A-2, GRCA, GPR162, G-protein coupled receptor 162, Gene-rich cluster gene A protein, gene rich cluster, A, probable G-protein coupled receptor 162, Gpr162_predicted, Grca_predicted, LOC362436, G protein-coupled receptor 162, G protein-coupled receptor 162 (predicted), gene rich cluster, A gene (predicted), BC031437
Genes	GPR162 (Hs), Gpr162 (Mm), Gpr162 (Rn)
Ensembl ID	ENSG00000250510 (Hs), ENSMUSG00000038390 (Mm), ENSRNOG00000016143 (Rn)
UniProtKB AC	Q16538 (Hs), Q3UN16 (Mm)
Principal transduction	-

GPR171 Show summary »« Hide summary More detailed page

Nomenclature	GPR171
Previous and unofficial names	F730001G15Rik, H963, GPR171, G-protein coupled receptor 171, G protein-coupled receptor 171, G-protein coupled receptor H963, platelet activating receptor homolog, probable G-protein coupled receptor 171, LOC688737, similar to G protein-coupled receptor 171
Genes	GPR171 (Hs), Gpr171 (Mm), Gpr171 (Rn)
Ensembl ID	ENSG00000174946 (Hs), ENSMUSG00000050075 (Mm), ENSRNOG00000025297 (Rn)
UniProtKB AC	O14626 (Hs), Q8CIF3 (Mm)
Principal transduction	-
Comment	GPR171 has been shown to be activated by endogenous peptide BigLEN. This receptor-peptide interaction is believed to be involved in regulating feeding and metabolism responses [30].

GPR173 Show summary »« Hide summary More detailed page

Nomenclature	GPR173
Previous and unofficial names	SREB3, Super conserved receptor expressed in brain 3, GPR173, G-protein coupled receptor 173, probable G-protein coupled receptor 173, G protein coupled receptor 173, 3230401K02Rik
Genes	GPR173 (Hs), Gpr173 (Mm), Gpr173 (Rn)
Ensembl ID	ENSG00000184194 (Hs), ENSMUSG00000056679 (Mm), ENSRNOG00000003272 (Rn)
UniProtKB AC	Q9NS66 (Hs), Q6PI62 (Mm), Q9JJH2 (Rn)
Principal transduction	-

GPR174 Show summary »« Hide summary More detailed page

Nomenclature

GPR174

Previous and unofficial names

RGD1564689, FKSG79, Gpr174_predicted, LOC302373, RGD1564689_predicted, G protein-coupled receptor 174, G protein-coupled receptor 174 (predicted), probable G-protein coupled receptor 174, similar to putative purinergic receptor FKSG79, similar to putative purinergic receptor FKSG79 (predicted), LOC213439, Gm376

Genes

GPR174 (Hs), Gpr174 (Mm), Gpr174 (Rn)

Ensembl ID

ENSG00000147138 (Hs), ENSMUSG00000073008 (Mm), ENSRNOG00000032970 (Rn)

UniProtKB AC

Q9BXC1 (Hs), Q3U507 (Mm)

Principal transduction

G_s

Endogenous agonists
(pK_i)

lysophosphatidylserine (pEC₅₀ 7.1) [43]

GPR176 Show summary »« Hide summary More detailed page

Nomenclature	GPR176
Previous and unofficial names	AGR9, Gm1012, HB954, GPR176, G-protein coupled receptor 176, HB-954, probable G-protein coupled receptor 176, Gpr, RBU-15, G-protein coupled receptor AGR9, gene model 1012, (NCBI), putative G protein coupled receptor, LOC381413
Genes	GPR176 (Hs), Gpr176 (Mm), Gpr176 (Rn)
Ensembl ID	ENSG00000166073 (Hs), ENSMUSG00000040133 (Mm), ENSRNOG00000005971 (Rn)
UniProtKB AC	Q14439 (Hs), Q80WT4 (Mm), Q64017 (Rn)
Principal transduction	-

GPR182 Show summary »« Hide summary More detailed page

Nomenclature	GPR182
Previous and unofficial names	hrhAMR, AM-R, G10-D, Gpcr17, Gpcr22, MB10, NOW, ADMR, G-protein coupled receptor 182, GPR182, G10D, AMR, gamrh, adrenomedullin receptor, L1-R [96], G protein-coupled receptor 182
Genes	GPR182 (Hs), Gpr182 (Mm), Gpr182 (Rn)
Ensembl ID	ENSG00000166856 (Hs), ENSMUSG00000058396 (Mm), ENSRNOG00000004311 (Rn)
UniProtKB AC	O15218 (Hs), P43142 (Mm), P31392 (Rn)
Principal transduction	-
Comment	Rat GPR182 was first proposed as adrenomedullin receptor [48]. However, it was later reported that rat and human GPR182 did not respond to adrenomedullin [51] and GPR182 is not currently considered to be a genuine adrenomedullin receptor [35].

GPR183 Show summary »« Hide summary More detailed page

Nomenclature

GPR183

Previous and unofficial names

EBV-induced G-protein coupled receptor 2, EBI2, Epstein-Barr virus-induced gene 2, lymphocyte-specific G protein-coupled receptor, EBV-induced G protein-coupled receptor 2, GPR183, Epstein-Barr virus induced gene 2 (lymphocyte-specific G protein-coupled receptor), LOC679975, G protein-coupled receptor 183, G-protein coupled receptor 183, similar to EBV-induced G-protein coupled receptor 2 (EBI2)

Genes

GPR183 (Hs), Gpr183 (Mm), Gpr183 (Rn)

Ensembl ID

ENSG00000169508 (Hs), ENSMUSG00000051212 (Mm), ENSRNOG00000025094 (Rn)

UniProtKB AC

P32249 (Hs), Q3U6B2 (Mm), D4A7K7 (Rn)

Principal transduction

Endogenous agonists
(pK_i)

7α,25-dihydroxycholesterol (Selective) (pEC₅₀ 8.1 – 9.85) [32,69]

7α,27-dihydroxycholesterol (Selective) (pEC₅₀ 8.89) [69]

7β, 25-dihydroxycholesterol (Selective) (pEC₅₀ 8.68) [69]

7β, 27-dihydroxycholesterol (Selective) (pEC₅₀ 7.29) [69]

Comment

Two independent publications have shown that 7α,25-dihydroxycholesterol is an agonist of GPR183 and have demonstrated by mass spectrometry that this oxysterol is present endogenously in tissues [32,69]. Gpr183-deficient mice show reduction in the early antibody response to a T-dependent antigen. GPR183-deficient B cells fail to migrate to the outer follicle and instead stay in the follicle centre [50,93].

LGR4 Show summary »« Hide summary More detailed page

Nomenclature

LGR4

Previous and unofficial names

GPR48, LGR4, leucine-rich repeat-containing G protein-coupled receptor 4, G-protein coupled receptor 48, G protein-coupled receptor 48, leucine-rich repeat-containing G-protein coupled receptor 4, A330106J01Rik, A930009A08Rik

Genes

LGR4 (Hs), Lgr4 (Mm), Lgr4 (Rn)

Ensembl ID

ENSG00000205213 (Hs), ENSMUSG00000050199 (Mm), ENSRNOG00000005715 (Rn)

UniProtKB AC

Q9BXB1 (Hs), A2ARI4 (Mm), Q9Z2H4 (Rn)

Principal transduction

Endogenous agonists
(pK_i)

R-spondin-2 (RSPO2, Q6UXX9) (Selective) (pEC₅₀ 12.52) [11]

R-spondin-1 (RSPO1, Q2MKA7) (Selective) (pEC₅₀ 10.7) [11]

R-spondin-3 (RSPO3, Q9BXY4) (Selective) (pEC₅₀ 10.7) [11]

R-spondin-4 (RSPO4, Q2I0M5) (Selective) (pEC₅₀ 10.05) [11]

Comment

LGR4 does not couple to heterotrimeric G proteins or to β-arrestin when stimulated by the R-spondins, indicating a unique mechanism of action. R-spondins bind to LGR4, which specifically associates with Frizzled and LRPs—proteins that are activated by the extracellular Wnt molecules and then trigger canonical Wnt signalling to increase gene expression [11,21,99]. Gene disruption leads to multiple developmental disorders [44,74,109,122].

LGR5 Show summary »« Hide summary More detailed page

Nomenclature

LGR5

Previous and unofficial names

GPR49, LGR5, GPR67, FEX, HG38, MGC117008, Leucine-rich repeat-containing G protein-coupled receptor 5, G-protein coupled receptor 49, G-protein coupled receptor 67, G-protein coupled receptor HG38, orphan G protein-coupled receptor HG38, leucine-rich repeat-containing G-protein coupled receptor 5, GRP49, leucine-rich repeat-containing G protein-coupled receptor 5, G protein-coupled receptor 49, Gpr49_predicted, LOC299802, G protein-coupled receptor 49 (predicted), leucine rich repeat containing G protein coupled receptor 5

Genes

LGR5 (Hs), Lgr5 (Mm), Lgr5 (Rn)

Ensembl ID

ENSG00000139292 (Hs), ENSMUSG00000020140 (Mm), ENSRNOG00000004221 (Rn)

UniProtKB AC

O75473 (Hs), Q9Z1P4 (Mm)

Principal transduction

Endogenous agonists
(pK_i)

R-spondin-2 (RSPO2, Q6UXX9) (Selective) (pEC₅₀ 12.0) [11]

R-spondin-1 (RSPO1, Q2MKA7) (Selective) (pEC₅₀ 11.1) [11]

R-spondin-3 (RSPO3, Q9BXY4) (Selective) (pEC₅₀ 11.0) [11]

R-spondin-4 (RSPO4, Q2I0M5) (Selective) (pEC₅₀ 9.4) [11]

Comment

The four R-spondins can bind to LGR4, LGR5, and LGR6, which specifically associate with Frizzled and LRPs—proteins that are activated by extracellular Wnt molecules- and then trigger canonical Wnt signalling to increase gene expression [11,21].

LGR6 Show summary »« Hide summary More detailed page

MAS1 Show summary »« Hide summary More detailed page

Nomenclature

MAS1

Previous and unofficial names

MGC119966, MAS, angiotensin 1-7 receptor [95], c-mas, MAS proto-oncogene, MAS1 oncogene, angiotensin-(1-7) receptor, proto-oncogene Mas, Mas-1

Genes

MAS1 (Hs), Mas1 (Mm), Mas1 (Rn)

Ensembl ID

ENSG00000130368 (Hs), ENSMUSG00000068037 (Mm), ENSRNOG00000014971 (Rn)

UniProtKB AC

P04201 (Hs), P30554 (Mm), P12526 (Rn)

Principal transduction

G_q/G₁₁

Endogenous agonists
(pK_i)

angiotensin-(1-7) (AGT, P01019) (Selective) [104]

MAS1L Show summary »« Hide summary More detailed page

Nomenclature	MAS1L
Previous and unofficial names	MAS-L, MRG, dJ994E9.2, MAS-R, MGC119987, MAS1 oncogene-like
Genes	MAS1L (Hs)
Ensembl ID	ENSG00000237284 (Hs)
UniProtKB AC	P35410 (Hs)
Principal transduction	-

MRGPRD Show summary »« Hide summary More detailed page

Nomenclature

MRGPRD

Previous and unofficial names

MRGD, mrgD, MAS-related GPR, member D, TGR7, MRGPRD, Beta-alanine receptor, G-protein coupled receptor TGR7, mas-related G protein-coupled MRGD, mas-related G-protein coupled receptor member D, MrgD, MAS-related G-protein coupled receptor, member D, MAS-related gene D, MRGD G protein-coupled receptor, LOC211578, Gm499

Genes

MRGPRD (Hs), Mrgprd (Mm), Mrgprd (Rn)

Ensembl ID

ENSG00000172938 (Hs), ENSMUSG00000051207 (Mm), ENSRNOG00000013448 (Rn)

UniProtKB AC

Q8TDS7 (Hs), Q91ZB8 (Mm), Q7TN41 (Rn)

Principal transduction

G_i/G_o

Endogenous agonists
(pK_i)

β-alanine (pEC₅₀ 4.8) [107,110]

Comment

An endogenous peptide with a high degree of sequence similarity to angiotensin-(1-7) (AGT, P01019), alamandine, was shown to promote NO release in MrgD-transfected cells. The binding of alamandine to MRGPRD to was shown to be blocked by D-Pro⁷-angiotensin-(1–7), β-alanine and PD123319 [62]. Genetic ablation of MRGPRD+ neurons of adult mice decreased behavioural sensitivity to mechanical stimuli but not to thermal stimuli [13].

MRGPRE Show summary »« Hide summary More detailed page

Nomenclature	MRGPRE
Previous and unofficial names	mrgE, GPR167, MGC138408, MRGPRE, MRGE, G protein-coupled receptor 167, G-protein coupled receptor 167, mas-related G protein-coupled MRGE, mas-related G-protein coupled receptor member E, MAS-related GPR, member E, MAS-related G-protein coupled receptor, member E, MAS-related gene E, C130069N09Rik
Genes	MRGPRE (Hs), Mrgpre (Mm), Mrgpre (Rn)
Ensembl ID	ENSG00000184350 (Hs), ENSMUSG00000048965 (Mm), ENSRNOG00000020735 (Rn)
UniProtKB AC	Q86SM8 (Hs), Q91ZB7 (Mm), Q7TN40 (Rn)
Principal transduction	-

MRGPRF Show summary »« Hide summary More detailed page

Nomenclature	MRGPRF
Previous and unofficial names	GPR140, MGC21621, mrgF, MAS-related GPR, member F, MRGPRF, GPR168, RTA, MRGF, G protein-coupled receptor 168, G protein-coupled receptor 140, Mas-related gene F protein, G-protein coupled receptor 168, G-protein coupled receptor 14, mas-related G protein-coupled MRGF, seven transmembrane helix receptor, G protein-coupled receptor MrgF, mas-related G-protein coupled receptor member F, LOC266762, G protein coupled receptor (RTA), G protein coupled receptor Rca, G-protein coupled receptor RTA, MAS-related G-protein coupled receptor, member F, MAS-related gene F, BC019711
Genes	MRGPRF (Hs), Mrgprf (Mm), Mrgprf (Rn)
Ensembl ID	ENSG00000172935 (Hs), ENSMUSG00000031070 (Mm), ENSRNOG00000013426 (Rn)
UniProtKB AC	Q96AM1 (Hs), Q8VCJ6 (Mm), P23749 (Rn)
Principal transduction	-
Comment	MRGPRF has been reported to respond to stimulation by angiotensin metabolites [29].

MRGPRG Show summary »« Hide summary More detailed page

Nomenclature	MRGPRG
Previous and unofficial names	MAS-related GPR, member G, GPR169, mrgG, MRGG, EBRT2, MRGPRG, G protein-coupled receptor 169, G protein-coupled receptor Mrgg, MAS-related G-protein coupled receptor, member G, MAS-related gene G, mas-related G-protein coupled receptor member G, LOC381974, Gm1098
Genes	MRGPRG (Hs), Mrgprg (Mm), Mrgprg (Rn)
Ensembl ID	ENSG00000182170 (Hs), ENSMUSG00000050276 (Mm), ENSRNOG00000020734 (Rn)
UniProtKB AC	Q86SM5 (Hs), Q91ZB5 (Mm), Q7TN39 (Rn)
Principal transduction	-

MRGPRX1 Show summary »« Hide summary More detailed page

Nomenclature

MRGPRX1

Previous and unofficial names

Mas-related G-protein coupled receptor member X1, Sensory neuron-specific G-protein coupled receptor 1, Mrgc, Mrgprc, Mrgprc11, Snsr, Snsr1, MRGX1, SNSR3, Mrgprb2, SNSR4, MRGPRX1, G protein-coupled receptor MRGX1, G protein-coupled receptor SNSR3, MAS-related GPR, member X1, MrgX1

Genes

MRGPRX1 (Hs)

Ensembl ID

ENSG00000170255 (Hs)

UniProtKB AC

Q96LB2 (Hs)

Principal transduction

G_q/G₁₁

Endogenous agonists
(pK_i)

BAM8-22 (PENK, P01210) (Selective) (pEC₅₀ 5.3 – 7.8) [15,64,110]

Comment

Reported to mediate the sensation of itch [70,108]. Reports that BAM8-22 (PENK, P01210) was the most potent of a series of proenkephalin A–derived peptides as an agonist of MRGPRX1 in assays of calcium mobilisation and radioligand binding [64] were replicated in an independent study using a β-arrestin recruitment assay [110].

MRGPRX2 Show summary »« Hide summary More detailed page

Nomenclature

MRGPRX2

Previous and unofficial names

MRGX2, Mrgprb10, MAS-related GPR, member X2, MrgX2

Genes

MRGPRX2 (Hs)

Ensembl ID

ENSG00000183695 (Hs)

UniProtKB AC

Q96LB1 (Hs)

Principal transduction

Endogenous agonists
(pK_i)

PAMP-20 (ADM, P35318) (Selective) [47]

Selective agonists
(pK_i)

PAMP-12 (human) (pEC₅₀ 7.24 – 7.68) [47]

CST-14 {Sp: Mouse, Rat} (pEC₅₀ 6.9 – 7.6) [47,98,110]

Comment

A diverse range of substances has been reported to be agonists of MRGPRX2, with cortistatin 14 the highest potency agonist in assays of calcium mobilisation [98], also confirmed in an independent study using a β-arrestin recruitment assay [110].

MRGPRX3 Show summary »« Hide summary More detailed page

Nomenclature	MRGPRX3
Previous and unofficial names	MrgA, Mrgpra, MRGX3, Mrga10, SNSR1, SNSR2, Sensory neuron-specific G protein-coupled receptor 1/2, MAS-related GPR, member X3
Genes	MRGPRX3 (Hs)
Ensembl ID	ENSG00000179826 (Hs)
UniProtKB AC	Q96LB0 (Hs)
Principal transduction	G_q/G₁₁

MRGPRX4 Show summary »« Hide summary More detailed page

Nomenclature	MRGPRX4
Previous and unofficial names	MGC129753, MGC129754, MAS-related GPR, member X4, SNSR5, SNSR6, MRGX4, Sensory neuron-specific G protein-coupled receptor 5/6, Sensory neuron-specific G-protein coupled receptor 5/6, G protein-coupled receptor SNSR5, G protein-coupled receptor SNSR6, G protein-coupled receptor MRGX4, MRGPRX4
Genes	MRGPRX4 (Hs)
Ensembl ID	ENSG00000179817 (Hs)
UniProtKB AC	Q96LA9 (Hs)
Principal transduction	G_q/G₁₁

OPN3 Show summary »« Hide summary More detailed page

Nomenclature	OPN3
Previous and unofficial names	Opsin-3, Encephalopsin, Panopsin, ECPN, ERO, NMO-1, LOC498289, opsin 3, similar to Opsin-3 (Encephalopsin) (Panopsin)
Genes	OPN3 (Hs), Opn3 (Mm), Opn3 (Rn)
Ensembl ID	ENSG00000054277 (Hs), ENSMUSG00000026525 (Mm), ENSRNOG00000003778 (Rn)
UniProtKB AC	Q9H1Y3 (Hs), Q9WUK7 (Mm)
Principal transduction	-

OPN5 Show summary »« Hide summary More detailed page

Nomenclature	OPN5
Previous and unofficial names	opsin 5, transmembrane protein 13, dJ402H5.1, GPR136, PGR12, OPN5, neuropsin, PGR14, G-protein coupled receptor 136, Transmembrane protein 13, Neuropsin, opsin-5, G-protein coupled receptor PGR12, TMEM13, G protein-coupled receptor 136
Genes	OPN5 (Hs), Opn5 (Mm), Opn5 (Rn)
Ensembl ID	ENSG00000124818 (Hs), ENSMUSG00000043972 (Mm), ENSRNOG00000012689 (Rn)
UniProtKB AC	Q6U736 (Hs), Q6VZZ7 (Mm), Q7TQN6 (Rn)
Principal transduction	G_i/G_o
Comment	Evidence indicates OPN5 triggers a UV-sensitive G_i-mediated signalling pathway in mammalian tissues [56].

P2RY8 Show summary »« Hide summary More detailed page

Nomenclature	P2RY8
Previous and unofficial names	purinergic receptor P2Y, G-protein coupled, 8, P2Y8, MGC50878, P2RY8, G-protein coupled purinergic receptor P2Y8, purinergic receptor P2Y, G-protein coupled, 8, P2Y purinoceptor 8
Genes	P2RY8 (Hs)
Ensembl ID	ENSG00000182162 (Hs)
UniProtKB AC	Q86VZ1 (Hs)
Principal transduction	-

P2RY10 Show summary »« Hide summary More detailed page

Nomenclature

P2RY10

Previous and unofficial names

purinergic receptor P2Y, G-protein coupled, 10, P2Y-like receptor, P2Y10, purinergic receptor, P2Y-like, LOC317219, MGC189289, P2ry10_predicted, RGD1561912, RGD1561912_predicted, purinergic receptor P2Y, G-protein coupled 10 , purinergic receptor P2Y, G-protein coupled 10 (predicted), similar to purinergic receptor P2Y, G-protein coupled 10, similar to purinergic receptor P2Y, G-protein coupled 10 (predicted), 5830408N17Rik

Genes

P2RY10 (Hs), P2ry10 (Mm), P2ry10 (Rn)

Ensembl ID

ENSG00000078589 (Hs), ENSMUSG00000050921 (Mm), ENSRNOG00000037839 (Rn)

UniProtKB AC

O00398 (Hs), Q7TMT1 (Mm)

Principal transduction

Endogenous agonists
(pK_i)

sphingosine 1-phosphate (Selective) (pEC₅₀ 7.3) [82]

LPA (Selective) (pEC₅₀ 6.9) [82]

TAAR2 Show summary »« Hide summary More detailed page

Nomenclature	TAAR2
Previous and unofficial names	GPR58, TA₂, trace amine associated receptor 2, TAA2, G protein-coupled receptor 58, Gpr58_predicted, LOC294121, Taar2, G protein-coupled receptor 58 (predicted), G-protein coupled receptor 58, taR-2, trace amine receptor 2, trace amine-associated receptor 2, Gm225
Genes	TAAR2 (Hs), Taar2 (Mm), Taar2 (Rn)
Ensembl ID	ENSG00000146378 (Hs), ENSMUSG00000059763 (Mm), ENSRNOG00000025951 (Rn)
UniProtKB AC	Q9P1P5 (Hs), Q5QD17 (Mm), Q5QD25 (Rn)
Principal transduction	G_s
Rank order of potency	β-phenylethylamine > tryptamine [8]
Comment	Probable pseudogene in 10–15% of Asians due to a polymorphism (rs8192646) producing a premature stop codon at amino acid 168 [20].

TAAR3 Show summary »« Hide summary More detailed page

Nomenclature	TAAR3
Previous and unofficial names	trace amine associated receptor 3, GPR57, G protein-coupled receptor 57, taR-3, trace amine receptor 3, trace amine-associated receptor 3
Genes	TAAR3 (Hs), Taar3 (Mm), Taar3 (Rn)
Ensembl ID	ENSG00000179073 (Hs), ENSMUSG00000069708 (Mm), ENSRNOG00000025982 (Rn)
UniProtKB AC	Q9P1P4 (Hs), Q5QD16 (Mm), Q5QD24 (Rn)
Principal transduction	-
Comment	TAAR3 is thought to be a pseudogene in man though functional in rodents [20]

TAAR4P Show summary »« Hide summary More detailed page

Nomenclature	TAAR4P
Previous and unofficial names	Ta2, taR-2, taR-4, trace amine receptor 2, trace amine receptor 4, trace amine-associated receptor 4, trace-amine-associated receptor 4, Gm226
Genes	TAAR4P (Hs), Taar4 (Mm), Taar4 (Rn)
Ensembl ID	ENSMUSG00000069707 (Mm), ENSRNOG00000029877 (Rn)
UniProtKB AC	Q5QD15 (Mm), Q923Y7 (Rn)
Principal transduction	G_s
Comment	Pseudogene in man but functional in rodents [20].

TAAR5 Show summary »« Hide summary More detailed page

Nomenclature	TAAR5
Previous and unofficial names	Putative neurotransmitter receptor, PNR, MGC138414, MGC138416, RP11-295F4.5, TAAR5, Trace amine receptor, Trace amine receptor 5, trace amine-associated receptor 5, TaR-5, trace amine associated receptor 5, LOC215854, Gm227
Genes	TAAR5 (Hs), Taar5 (Mm), Taar5 (Rn)
Ensembl ID	ENSG00000135569 (Hs), ENSMUSG00000069706 (Mm), ENSRNOG00000039869 (Rn)
UniProtKB AC	O14804 (Hs), Q5QD14 (Mm), Q5QD23 (Rn)
Principal transduction	-

TAAR6 Show summary »« Hide summary More detailed page

Nomenclature	TAAR6
Previous and unofficial names	Trace amine-associated receptor 6, Trace amine receptor 4, TaR-4, TA4, TAR4, TRAR4, RP11-295F4.3, SCZD5, TAAR6, TA₄, taR-6, trace amine receptor 6, trace-amine-associated receptor 6, LOC215855, Gm228
Genes	TAAR6 (Hs), Taar6 (Mm), Taar6 (Rn)
Ensembl ID	ENSG00000146383 (Hs), ENSMUSG00000045111 (Mm), ENSRNOG00000016089 (Rn)
UniProtKB AC	Q96RI8 (Hs), Q5QD13 (Mm), Q923Y5 (Rn)
Principal transduction	-

TAAR8 Show summary »« Hide summary More detailed page

Nomenclature	TAAR8
Previous and unofficial names	trace amine associated receptor 8, trace amine receptor 5, TA5, TAR5, GPR102, TRAR5, TA11, TAR11, TRAR11, Gm1149, taR-11, taR-8a, trace amine receptor 11, trace amine receptor 8a, trace amine-associated receptor 8a, trace-amine-associated receptor 8a, LOC215859, Gm230
Genes	TAAR8 (Hs), Taar8a (Mm), Taar8a (Rn)
Ensembl ID	ENSG00000146385 (Hs), ENSMUSG00000050804 (Mm), ENSRNOG00000030414 (Rn)
UniProtKB AC	Q969N4 (Hs), Q5QD06 (Mm), Q923X9 (Rn)
Principal transduction	-

TAAR9 Show summary »« Hide summary More detailed page

Nomenclature	TAAR9
Previous and unofficial names	trace amine-associated receptor 9, TA3, TAR3, TRAR3, trace amine receptor 3, trace amine associated receptor 9, taR-3, taR-9, trace amine receptor 9, trace-amine-associated receptor 9, Gm231
Genes	TAAR9 (Hs), Taar9 (Mm), Taar9 (Rn)
Ensembl ID	ENSG00000237110 (Hs), ENSMUSG00000037424 (Mm), ENSRNOG00000026096 (Rn)
UniProtKB AC	Q96RI9 (Hs), Q5QD04 (Mm), Q923Y6 (Rn)
Principal transduction	-
Comment	TAAR9 appears to be functional in most individuals but has a polymorphic premature stop codon at amino acid 61 (rs2842899) with an allele frequency of 10–30% in different populations [119].

Class B Orphans

Overview

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The receptors in this family have been reclassified as Adhesion Class GPCRs

Class C Orphans

Receptors

GPR156 Show summary »« Hide summary More detailed page

Nomenclature	GPR156
Previous and unofficial names	MGC142261, ZK180.1-like, PGR28, DEPDC3, DEP.7, FLJ31819, PGR22, GABABL, G protein-coupled receptor 156, GABAB-related G-protein coupled receptor, probable G-protein coupled receptor 156
Genes	GPR156 (Hs), Gpr156 (Mm), Gpr156 (Rn)
Ensembl ID	ENSG00000175697 (Hs), ENSMUSG00000046961 (Mm), ENSRNOG00000002797 (Rn)
UniProtKB AC	Q8NFN8 (Hs), Q6PCP7 (Mm), Q8K451 (Rn)
Principal transduction	-

GPR158 Show summary »« Hide summary More detailed page

Nomenclature	GPR158
Previous and unofficial names	FLJ37801, RP11-59G22.1, FLJ12132, KIAA1136, Gpr158_predicted, LOC291352, G protein-coupled receptor 158, G protein-coupled receptor 158 (predicted), probable G-protein coupled receptor 158, 5330427M13Rik
Genes	GPR158 (Hs), Gpr158 (Mm), Gpr158 (Rn)
Ensembl ID	ENSG00000151025 (Hs), ENSMUSG00000045967 (Mm), ENSRNOG00000024832 (Rn)
UniProtKB AC	Q5T848 (Hs), Q8C419 (Mm), D4A6L0 (Rn)
Principal transduction	-

GPR179 Show summary »« Hide summary More detailed page

Nomenclature	GPR179
Previous and unofficial names	GPR158-like 1, GPR158L1, GPR179, LOC287657, RGD1560033, RGD1560033_predicted, G protein-coupled receptor 179, similar to GPR158-like 1, similar to GPR158-like 1 (predicted), 5330439C02Rik
Genes	GPR179 (Hs), Gpr179 (Mm), Gpr179 (Rn)
Ensembl ID	ENSG00000188888 (Hs), ENSMUSG00000070337 (Mm), ENSRNOG00000029245 (Rn)
UniProtKB AC	Q6PRD1 (Hs)
Principal transduction	-

GPRC5A Show summary »« Hide summary More detailed page

Nomenclature	GPRC5A
Previous and unofficial names	RAIG1, Gprc5a, retinoic acid induced 3, RAIG₁, Retinoic acid-induced protein 3, G protein-coupled receptor family C group 5 member A, retinoic acid-induced gene 1 protein, RAIG-1, orphan G protein-coupling receptor PEIG-1, RAI3, GPCR5A, LOC312790, MGC156777, Rai3_predicted, G protein-coupled receptor, family C, group 5, member A, retinoic acid induced 3 (predicted)
Genes	GPRC5A (Hs), Gprc5a (Mm), Gprc5a (Rn)
Ensembl ID	ENSG00000013588 (Hs), ENSMUSG00000046733 (Mm), ENSRNOG00000008412 (Rn)
UniProtKB AC	Q8NFJ5 (Hs), Q8BHL4 (Mm)
Principal transduction	-

GPRC5B Show summary »« Hide summary More detailed page

Nomenclature	GPRC5B
Previous and unofficial names	RAIG₂, G protein-coupled receptor family C group 5 member B, retinoic acid-induced gene 2 protein, RAIG-2, A-69G12.1, G protein-coupled receptor, family C, group 1, member B, Gprc5b_predicted, LOC293546, G protein-coupled receptor, family C, group 5, member B, G protein-coupled receptor, family C, group 5, member B (predicted), G-protein coupled receptor family C group 5 member B, hypothetical protein, clone 2-63, AW125761
Genes	GPRC5B (Hs), Gprc5b (Mm), Gprc5b (Rn)
Ensembl ID	ENSG00000167191 (Hs), ENSMUSG00000008734 (Mm), ENSRNOG00000016013 (Rn)
UniProtKB AC	Q9NZH0 (Hs), Q923Z0 (Mm)
Principal transduction	-

GPRC5C Show summary »« Hide summary More detailed page

Nomenclature	GPRC5C
Previous and unofficial names	RAIG₃, G protein-coupled receptor family C group 5 member C, retinoic acid-induced gene 3 protein, RAIG-3, Gprc5c_predicted, LOC287805, G protein-coupled receptor, family C, group 5, member C (predicted), G-protein coupled receptor family C group 5 member C, 3200002M13Rik, 1110028I06Rik
Genes	GPRC5C (Hs), Gprc5c (Mm), Gprc5c (Rn)
Ensembl ID	ENSG00000170412 (Hs), ENSMUSG00000051043 (Mm), ENSRNOG00000003144 (Rn)
UniProtKB AC	Q9NQ84 (Hs), Q8K3J9 (Mm), Q3KRC4 (Rn)
Principal transduction	-

GPRC5D Show summary »« Hide summary More detailed page

Nomenclature	GPRC5D
Previous and unofficial names	RAIG₄, G protein-coupled receptor family C group 5 member D, LOC500349, RGD1563887, RGD1563887_predicted, G protein-coupled receptor, family C, group 5, member D, G-protein coupled receptor family C group 5 member D, similar to G protein-coupled receptor family C group 5 member D, similar to G protein-coupled receptor family C group 5 member D (predicted)
Genes	GPRC5D (Hs), Gprc5d (Mm), Gprc5d (Rn)
Ensembl ID	ENSG00000111291 (Hs), ENSMUSG00000030205 (Mm), ENSRNOG00000008439 (Rn)
UniProtKB AC	Q9NZD1 (Hs), Q9JIL6 (Mm)
Principal transduction	-

Taste 1 receptors

Overview

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Whilst the taste of acid and salty foods appear to be sensed by regulation of ion channel activity, bitter, sweet and umami tastes are sensed by specialised GPCR. Two classes of taste GPCR have been identified, T1R and T2R, which are similar in sequence and structure to Class C and Class A GPCR, respectively. Activation of taste receptors appears to involve gustducin- (Gαt3) and Gα14-mediated signalling, although the precise mechanisms remain obscure. Gene disruption studies suggest the involvement of PLCβ2 [132], TRPM5 [132] and IP3 [37] receptors in post-receptor signalling of taste receptors. Although predominantly associated with the oral cavity, taste receptors are also located elsewhere, including further down the gastrointestinal system, in the lungs and in the brain.

Sweet/Umami
T1R3 acts as an obligate partner in T1R1/T1R3 and T1R2/T1R3 heterodimers, which sense umami or sweet, respectively. T1R1/T1R3 heterodimers respond to L-glutamic acid and may be positively allosterically modulated by 5’-nucleoside monophosphates, such as 5'-GMP [67]. T1R2/T1R3 heterodimers respond to sugars, such as sucrose, and artificial sweeteners, such as saccharin [84].

Receptors

TAS1R1 Show summary »« Hide summary More detailed page

Nomenclature	TAS1R1
Previous and unofficial names	taste receptor type 1 member 1, TAS1R1, T1R1, GPR70, TR1, G protein-coupled receptor 70, G-protein coupled receptor 70, taste receptor, type 1, member 1
Genes	TAS1R1 (Hs), Tas1r1 (Mm), Tas1r1 (Rn)
Ensembl ID	ENSG00000173662 (Hs), ENSMUSG00000028950 (Mm), ENSRNOG00000009708 (Rn)
UniProtKB AC	Q7RTX1 (Hs), Q3U5H1 (Mm), Q9Z0R8 (Rn)
Principal transduction	-
Comment	TAS1R1 is a putative sweet taste receptor

TAS1R2 Show summary »« Hide summary More detailed page

Nomenclature	TAS1R2
Previous and unofficial names	taste receptor type 1 member 2, T1R2, TAS1R2, GPR71, TR2, G protein-coupled receptor 71
Genes	TAS1R2 (Hs), Tas1r2 (Mm)
Ensembl ID	ENSG00000179002 (Hs), ENSMUSG00000028738 (Mm), ENSRNOG00000018608 (Rn)
UniProtKB AC	Q8TE23 (Hs), Q925I4 (Mm)
Principal transduction	-
Comment	TAS1R2 is a putative sweet taste receptor

TAS1R3 Show summary »« Hide summary More detailed page

Nomenclature	TAS1R3
Previous and unofficial names	T1R3, sweet taste receptor T1R3, taste receptor type 1 member 3, taste receptor, type 1, member 3
Genes	TAS1R3 (Hs), Tas1r3 (Mm), Tas1r3 (Rn)
Ensembl ID	ENSG00000169962 (Hs), ENSMUSG00000029072 (Mm), ENSRNOG00000019589 (Rn)
UniProtKB AC	Q7RTX0 (Hs), Q925D8 (Mm), Q923K1 (Rn)
Principal transduction	-
Comment	TAS1R3 is a putative sweet taste receptor

Taste 2 receptors

Overview

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Whilst the taste of acid and salty foods appear to be sensed by regulation of ion channel activity, bitter, sweet and umami tastes are sensed by specialised GPCR. Two classes of taste GPCR have been identified, T1R and T2R, which are similar in sequence and structure to Class C and Class A GPCR, respectively. Activation of taste receptors appears to involve gustducin- (Gαt3) and Gα14-mediated signalling, although the precise mechanisms remain obscure. Gene disruption studies suggest the involvement of PLCβ2 [132], TRPM5 [132] and IP3 [37] receptors in post-receptor signalling of taste receptors. Although predominantly associated with the oral cavity, taste receptors are also located elsewhere, including further down the gastrointestinal system, in the lungs and in the brain.

Bitter
The composition and stoichiometry of bitter taste receptors is not yet established. Bitter receptors appear to separate into two groups, with very restricted ligand specificity or much broader responsiveness. For example, T2R5 responded to cycloheximide, but not 10 other bitter compounds [14], while T2R14 responded to at least eight different bitter tastants, including (-)-α-thujone and picrotoxinin [5].

Receptors

TAS2R1 Show summary »« Hide summary

Nomenclature	TAS2R1
Previous and unofficial names	T2R1, TRB7
Genes	TAS2R1 (Hs)
Ensembl ID	ENSG00000169777 (Hs)
UniProtKB AC	Q9NYW7 (Hs)
Principal transduction	-

TAS2R3 Show summary »« Hide summary

Nomenclature	TAS2R3
Previous and unofficial names	T2R3
Genes	TAS2R3 (Hs)
Ensembl ID	ENSG00000127362 (Hs)
UniProtKB AC	Q9NYW6 (Hs)
Principal transduction	-

TAS2R4 Show summary »« Hide summary

Nomenclature	TAS2R4
Previous and unofficial names	T2R4
Genes	TAS2R4 (Hs)
Ensembl ID	ENSG00000127364 (Hs)
UniProtKB AC	Q9NYW5 (Hs)
Principal transduction	-

TAS2R5 Show summary »« Hide summary

Nomenclature	TAS2R5
Previous and unofficial names	T2R5
Genes	TAS2R5 (Hs)
Ensembl ID	ENSG00000127366 (Hs)
UniProtKB AC	Q9NYW4 (Hs)
Principal transduction	-

TAS2R7 Show summary »« Hide summary

Nomenclature	TAS2R7
Previous and unofficial names	T2R7, TRB4
Genes	TAS2R7 (Hs)
Ensembl ID	ENSG00000121377 (Hs)
UniProtKB AC	Q9NYW3 (Hs)
Principal transduction	-

TAS2R8 Show summary »« Hide summary

Nomenclature	TAS2R8
Previous and unofficial names	T2R8, TRB5
Genes	TAS2R8 (Hs)
Ensembl ID	ENSG00000121314 (Hs)
UniProtKB AC	Q9NYW2 (Hs)
Principal transduction	-

TAS2R9 Show summary »« Hide summary

Nomenclature	TAS2R9
Previous and unofficial names	T2R9, TRB6
Genes	TAS2R9 (Hs)
Ensembl ID	ENSG00000121381 (Hs)
UniProtKB AC	Q9NYW1 (Hs)
Principal transduction	-

TAS2R10 Show summary »« Hide summary

Nomenclature	TAS2R10
Previous and unofficial names	T2R10, TRB2
Genes	TAS2R10 (Hs)
Ensembl ID	ENSG00000121318 (Hs)
UniProtKB AC	Q9NYW0 (Hs)
Principal transduction	-

TAS2R13 Show summary »« Hide summary

Nomenclature	TAS2R13
Previous and unofficial names	T2R13, TRB3
Genes	TAS2R13 (Hs)
Ensembl ID	ENSG00000212128 (Hs)
UniProtKB AC	Q9NYV9 (Hs)
Principal transduction	-

TAS2R14 Show summary »« Hide summary

Nomenclature	TAS2R14
Previous and unofficial names	T2R14, TRB1
Genes	TAS2R14 (Hs)
Ensembl ID	ENSG00000212127 (Hs)
UniProtKB AC	Q9NYV8 (Hs)
Principal transduction	-

TAS2R16 Show summary »« Hide summary

Orphan and other 7TM receptors

Jump to

Class A Orphans

Overview

Receptors

Class B Orphans

Overview

Class C Orphans

Receptors

Taste 1 receptors

Overview

Receptors

Taste 2 receptors

Overview

Receptors