<i>GPR65</i> | Class A Orphans | IUPHAR Guide to IMMUNOPHARMACOLOGY

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Target id: 113

Nomenclature: GPR65

Family: Class A Orphans

Annotation status:  image of a green circle Annotated and expert reviewed. Please contact us if you can help with updates.  » Email us

   GtoImmuPdb view: ON :     GPR65 has curated data in GtoImmuPdb

Gene and Protein Information
class A G protein-coupled receptor
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human 7 337 14q31-q32.1 GPR65 G protein-coupled receptor 65 10
Mouse 7 337 12 E Gpr65 G-protein coupled receptor 65
Rat 7 337 6q32 Gpr65 G-protein coupled receptor 65
Previous and Unofficial Names
Dig1 | Gpcr25 | Psychosine receptor | TDAG8 | T cell death associated protein 8
Database Links
Specialist databases
GPCRDB psyr_human (Hs), psyr_mouse (Mm)
Other databases
Ensembl Gene
Entrez Gene
Human Protein Atlas
RefSeq Nucleotide
RefSeq Protein
Natural/Endogenous Ligands
Agonist Comments
It was initially believed that psychosine and other lysolipids acted at human GPR65 to inhibit of forskolin-stimulated cAMP formation in a concentration- dependent manner [6]. However, GPR4, GPR 65, GPR68 and GPR132 are now thought to function as proton-sensing receptors detecting acidic pH [2,22]; lysolipids may actually be antagonists at GPR65 [22,24]. BTB09089 has been reported to be an agonist of GPR65 [17].
Antagonist Comments
Psychosine related lysoslipids behave as antagonists against proton-sensing GPR65 [24].
Primary Transduction Mechanisms
Transducer Effector/Response
Gs family Adenylate cyclase stimulation
Comments:  GPR65 response to psychosine was not blocked by pre-treatment of RH7777 cells with pertussis toxin, suggesting the involvement of PTX-insensitive G proteins, perhaps Gαs. Proton stimulation of the receptor causes cAMP accumulation [7,19]. This proton-receptor interaction may be mediated by Gs proteins [24]. GPR65 mediates, at least partly, inhibition of proinflammatory cytokine production induced by the extracellular acidification through Gs protein/cAMP/PKA.
References:  7,15,19,24
Tissue Distribution
Natural killer cells, monocytic cell lines (U937,THP-1)
Species:  Human
Technique:  RT-PCR
References:  12
Peripheral blood leukocytes, spleen, lymph nodes, thymus
Species:  Human
Technique:  Northern blot
References:  10
Differentiated HL-60 cells, neutrophils
Species:  Human
Technique:  qRT-PCR
References:  16
Monocytes, macrophages
Species:  Human
Technique:  RT-PCR, immunoblotting
References:  3
Spleen, lymph node, peripheral blood leukocytes (low level expression in all tissue extracts)
Species:  Human
Technique:  Microarray analysis
References:  6
Peritoneal macrophages
Species:  Mouse
Technique:  RT-PCR
References:  15
Brain, spinal cord, dorsal root ganglion, and trigeminal ganglion
Species:  Mouse
Technique:  RT-PCR
References:  5
Species:  Mouse
Technique:  Northern blot
References:  9
Hypothalamus, amygdala, hippocampus, frontal cortex, striatum, medulla
Species:  Rat
Technique:  RT-PCR
References:  14
Tissue Distribution Comments
GPR65 is overexpressed by more than 5x in a range of human cancer tissues (kidney, ovarian, colon, breast) screened using quantitative fluorescence-based real-time PCR [23]. Enhanced green fluorescent protein reporter has been knocked into the disrupted GPR65 locus to allow the analysis of TDAG8 expression in living cells [18]. GPR65 is expressed in nociceptors of the lumbar dorsal root ganglion in mice (RT-PCR) [5]. Receptor expression is increased in eosinophils in murine models of allergic asthma and human populations during acute asthma exacerbations [9].
Expression Datasets

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Log average relative transcript abundance in mouse tissues measured by qPCR from Regard, J.B., Sato, I.T., and Coughlin, S.R. (2008). Anatomical profiling of G protein-coupled receptor expression. Cell, 135(3): 561-71. [PMID:18984166] [Raw data: website]

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Functional Assays
Psychosine induces multinuclear cells in GPR65-expressing RH7777 cultures
Species:  Human
Tissue:  RH777 hepatoma cells
Response measured:  Globoid cell formation
References:  3
Murine GPR65 is upregulated during apoptosis of immature thymocytes as a result of activation with either anti-CD3 plus anti-CD28 or with glucocorticoids
Species:  Mouse
Tissue:  Lymphoid tissues
Response measured:  Receptor upregulation
References:  1
Expression of GPR65 in WHEI7.2 cells is sufficient to induce apoptosis
Species:  Mouse
Tissue:  WHEI7.2 lymphoma cell culture
Response measured:  Apoptosis
References:  13
Glucocorticoids induce GPR65 expression in multiple models of glucocorticoid-mediated apoptosis
Species:  Mouse
Tissue:  WEHI7.2 cells, S49.A2 cells, primary thymocytes
Response measured:  Receptor activation by psychosine enhances dexamethasone-mediated apoptosis
References:  13
Site directed mutagenesis of conserved H17 and H20 indicates that these residues are required for the proton-sensing ability of GPR65
Species:  Human
Tissue:  COS7 cells
Response measured:  Proton-insensitivity
References:  24
Increased cAMP and phosphorylated CREB concentrations are observed in GPR65 expressing cells. Acidosis-induced toxicity is also attenuated
Species:  Rat
Tissue:  Transfected CHO cells
Response measured:  Increased intracellular cAMP and phosphorylated CREB
References:  14
Functional Assay Comments
Cell-based fluorescence imaging system successfully monitored the internalization of the proton-sensing GPR65 [4].
Physiological Functions
Enhances glucocorticoid-mediated apoptosis
Species:  Mouse
Tissue:  Leukocyte cell lines
References:  13
GPR65 regulates viability of allergen-elicited BALF eosinophils, most likely through a caspase-dependent mechanism
Species:  Mouse
Tissue:  Eosinophils
References:  9
Physiological Functions Comments
Receptor mediated increased intracellular cAMP concentration may mediate the acidic pH-induced inhibition of superoxide anion production [16].
Physiological Consequences of Altering Gene Expression
Pro-survival phenotype. Repression of GPR65 inhibits dexamethasone mediated apoptosis
Species:  Mouse
Tissue:  WHEI7.2 lymphoma cell line
Technique:  RNA interference (RNAi)
References:  13
Overexpression of TDAG8 in HEK293 cells leads to transcriptional activation from SRE- and CRE-driven promoters, independent of exogenously added ligand. This leads to a tumour-formation phenotype
Species:  Human
Tissue:  HEK293 cell line
Technique:  Gene over-expression
References:  23
Ectopic overexpression of GPR65 causes up to 10x increase in cAMP production, even in alkaline conditions. This increase in cAMP was amplified in acidic conditions.
Species:  Human
Tissue:  293T cells
Technique:  Gene over-expression
References:  19
GPR65 homozygous knockout ablates the acid-dependent upregulation of cAMP production, and inhibits the acid-induced increase in eosinophil viability.
Species:  Mouse
Tissue:  Eosinophils
Technique:  Gene knockouts
References:  9
siRNA specific to GPR65 (TDAG8), but not to GPR132 (G2A), clearly attenuated the acidification-induced inhibition of TNF-alpha, but not isoproterenol or prostaglandin-E2, in mouse peritoneal macrophages
Species:  Mouse
Tissue:  Peritoneal macrophages
Technique:  RNA interference (RNAi)
References:  15
Knockdown of GPR65 prevented the elevation of Bcl-2 and Bcl-xL in response to acidic conditions, due to inhibition of MEK/ERK signalling
Species:  Human
Tissue:  WEHI7.2 cells
Technique:  RNA interference (RNAi)
References:  21
GPR65 is required for pH-dependent cAMP production in immune cells
Species:  Mouse
Tissue:  Thymocytes and splenocytes
Technique:  Genomic DNA fragment containing exon 2-derived coding sequences was replaced by a construct encoding promoterless IRES-EGFP sequences and the neomycin resistance cassette flanked by loxP sites. Mice were back-crossed for 6 generations.
References:  19
Knockout of GPR65 has no effect on thymocyte maturation, selection, or on major immune functions. Thymocytes also displayed normal apoptosis following glucocorticoid treatment
Species:  Mouse
Tissue:  Thymocytes
Technique:  Gene knock-outs
References:  18
Physiological Consequences of Altering Gene Expression Comments
Gene profiling of GPR65 indicates that mRNA is down regulated in leukemic cells overexpressing growth factor independence 1B gene [8].
Phenotypes, Alleles and Disease Models Mouse data from MGI

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Allele Composition & genetic background Accession Phenotype Id Phenotype Reference
Gpr65tm1Witt Gpr65tm1Witt/Gpr65tm1Witt
MGI:108031  MP:0001819 abnormal immune cell physiology PMID: 15665078 
Gpr65tm1Witt Gpr65tm1Witt/Gpr65tm1Witt
MGI:108031  MP:0002442 abnormal leukocyte physiology PMID: 15665078 
Gpr65tm1Witt Gpr65tm1Witt/Gpr65tm1Witt
MGI:108031  MP:0002442 abnormal leukocyte physiology PMID: 15665078 
Gpr65Tn(sb-lacZ,GFP)T1.88Jtak Gpr65Tn(sb-lacZ,GFP)T1.88Jtak/Gpr65Tn(sb-lacZ,GFP)T1.88Jtak
MGI:108031  MP:0002451 abnormal macrophage physiology PMID: 19234222 
Gpr65Tn(sb-lacZ,GFP)T1.88Jtak Gpr65Tn(sb-lacZ,GFP)T1.88Jtak/Gpr65Tn(sb-lacZ,GFP)T1.88Jtak
MGI:108031  MP:0008561 decreased tumor necrosis factor secretion PMID: 19234222 
Gene Expression and Pathophysiology Comments
Chromosomal location and tissue distribution implicates GPR65 in T-cell-associated diseases [10]. Association with the ligand psychosine indicates a role for the receptor in globoid cell leukodystrophy [6]. Receptor overexpression in a range of human cancer tissues suggest contribution to tumor development [23]. Genome-wide association and fine mapping of genetic loci indicates Gpr65 in predisposition to colon carcinogenesis in mice [11].
Biologically Significant Variants
Type:  Single nucleotide polymorphism
Species:  Human
Amino acid change:  I231L
Global MAF (%):  14
Subpopulation MAF (%):  AFR|AMR|ASN|EUR: 18|13|19|9
Minor allele count:  C=0.144/314
SNP accession: 
Validation:  1000 Genomes, HapMap, Frequency
General Comments
GPR65 may be a Stat3alpha gene target [20].


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1. Choi JW, Lee SY, Choi Y. (1996) Identification of a putative G protein-coupled receptor induced during activation-induced apoptosis of T cells. Cell. Immunol., 168 (1): 78-84. [PMID:8599842]

2. Davenport AP, Alexander SP, Sharman JL, Pawson AJ, Benson HE, Monaghan AE, Liew WC, Mpamhanga CP, Bonner TI, Neubig RR et al.. (2013) International Union of Basic and Clinical Pharmacology. LXXXVIII. G protein-coupled receptor list: recommendations for new pairings with cognate ligands. Pharmacol. Rev., 65 (3): 967-86. [PMID:23686350]

3. Duong CQ, Bared SM, Abu-Khader A, Buechler C, Schmitz A, Schmitz G. (2004) Expression of the lysophospholipid receptor family and investigation of lysophospholipid-mediated responses in human macrophages. Biochim. Biophys. Acta, 1682 (1-3): 112-9. [PMID:15158762]

4. Fukunaga S, Setoguchi S, Hirasawa A, Tsujimoto G. (2006) Monitoring ligand-mediated internalization of G protein-coupled receptor as a novel pharmacological approach. Life Sci., 80 (1): 17-23. [PMID:16978657]

5. Huang CW, Tzeng JN, Chen YJ, Tsai WF, Chen CC, Sun WH. (2007) Nociceptors of dorsal root ganglion express proton-sensing G-protein-coupled receptors. Mol. Cell. Neurosci., 36 (2): 195-210. [PMID:17720533]

6. Im DS, Heise CE, Nguyen T, O'Dowd BF, Lynch KR. (2001) Identification of a molecular target of psychosine and its role in globoid cell formation. J. Cell Biol., 153 (2): 429-34. [PMID:11309421]

7. Ishii S, Kihara Y, Shimizu T. (2005) Identification of T cell death-associated gene 8 (TDAG8) as a novel acid sensing G-protein-coupled receptor. J. Biol. Chem., 280 (10): 9083-7. [PMID:15618224]

8. Koldehoff M, Zakrzewski JL, Klein-Hitpass L, Beelen DW, Elmaagacli AH. (2008) Gene profiling of growth factor independence 1B gene (Gfi-1B) in leukemic cells. Int. J. Hematol., 87 (1): 39-47. [PMID:18224412]

9. Kottyan LC, Collier AR, Cao KH, Niese KA, Hedgebeth M, Radu CG, Witte ON, Khurana Hershey GK, Rothenberg ME, Zimmermann N. (2009) Eosinophil viability is increased by acidic pH in a cAMP- and GPR65-dependent manner. Blood, 114 (13): 2774-82. [PMID:19641187]

10. Kyaw H, Zeng Z, Su K, Fan P, Shell BK, Carter KC, Li Y. (1998) Cloning, characterization, and mapping of human homolog of mouse T-cell death-associated gene. DNA Cell Biol., 17 (6): 493-500. [PMID:9655242]

11. Liu P, Lu Y, Liu H, Wen W, Jia D, Wang Y, You M. (2012) Genome-wide association and fine mapping of genetic loci predisposing to colon carcinogenesis in mice. Mol. Cancer Res., 10 (1): 66-74. [PMID:22127497]

12. Maghazachi AA, Knudsen E, Jin Y, Jenstad M, Chaudhry FA. (2004) D-galactosyl-beta1-1'-sphingosine and D-glucosyl-beta1-1'-sphingosine induce human natural killer cell apoptosis. Biochem. Biophys. Res. Commun., 320 (3): 810-5. [PMID:15240120]

13. Malone MH, Wang Z, Distelhorst CW. (2004) The glucocorticoid-induced gene tdag8 encodes a pro-apoptotic G protein-coupled receptor whose activation promotes glucocorticoid-induced apoptosis. J. Biol. Chem., 279 (51): 52850-9. [PMID:15485889]

14. McGuire J, Herman JP, Ghosal S, Eaton K, Sallee FR, Sah R. (2009) Acid-sensing by the T cell death-associated gene 8 (TDAG8) receptor cloned from rat brain. Biochem. Biophys. Res. Commun., 386 (3): 420-5. [PMID:19501050]

15. Mogi C, Tobo M, Tomura H, Murata N, He XD, Sato K, Kimura T, Ishizuka T, Sasaki T, Sato T, Kihara Y, Ishii S, Harada A, Okajima F. (2009) Involvement of proton-sensing TDAG8 in extracellular acidification-induced inhibition of proinflammatory cytokine production in peritoneal macrophages. J. Immunol., 182 (5): 3243-51. [PMID:19234222]

16. Murata N, Mogi C, Tobo M, Nakakura T, Sato K, Tomura H, Okajima F. (2009) Inhibition of superoxide anion production by extracellular acidification in neutrophils. Cell. Immunol., 259 (1): 21-6. [PMID:19539899]

17. Onozawa Y, Fujita Y, Kuwabara H, Nagasaki M, Komai T, Oda T. (2012) Activation of T cell death-associated gene 8 regulates the cytokine production of T cells and macrophages in vitro. Eur. J. Pharmacol., 683 (1-3): 325-31. [PMID:22445881]

18. Radu CG, Cheng D, Nijagal A, Riedinger M, McLaughlin J, Yang LV, Johnson J, Witte ON. (2006) Normal immune development and glucocorticoid-induced thymocyte apoptosis in mice deficient for the T-cell death-associated gene 8 receptor. Mol. Cell. Biol., 26 (2): 668-77. [PMID:16382156]

19. Radu CG, Nijagal A, McLaughlin J, Wang L, Witte ON. (2005) Differential proton sensitivity of related G protein-coupled receptors T cell death-associated gene 8 and G2A expressed in immune cells. Proc. Natl. Acad. Sci. U.S.A., 102 (5): 1632-7. [PMID:15665078]

20. Redell MS, Tsimelzon A, Hilsenbeck SG, Tweardy DJ. (2007) Conditional overexpression of Stat3alpha in differentiating myeloid cells results in neutrophil expansion and induces a distinct, antiapoptotic and pro-oncogenic gene expression pattern. J. Leukoc. Biol., 82 (4): 975-85. [PMID:17634277]

21. Ryder C, McColl K, Zhong F, Distelhorst CW. (2012) Acidosis Promotes Bcl-2 Family-mediated Evasion of Apoptosis: INVOLVEMENT OF ACID-SENSING G PROTEIN-COUPLED RECEPTOR GPR65 SIGNALING TO MEK/ERK. J. Biol. Chem., 287 (33): 27863-75. [PMID:22685289]

22. Seuwen K, Ludwig MG, Wolf RM. (2006) Receptors for protons or lipid messengers or both?. J. Recept. Signal Transduct. Res., 26 (5-6): 599-610. [PMID:17118800]

23. Sin WC, Zhang Y, Zhong W, Adhikarakunnathu S, Powers S, Hoey T, An S, Yang J. (2004) G protein-coupled receptors GPR4 and TDAG8 are oncogenic and overexpressed in human cancers. Oncogene, 23 (37): 6299-303. [PMID:15221007]

24. Wang JQ, Kon J, Mogi C, Tobo M, Damirin A, Sato K, Komachi M, Malchinkhuu E, Murata N, Kimura T, Kuwabara A, Wakamatsu K, Koizumi H, Uede T, Tsujimoto G, Kurose H, Sato T, Harada A, Misawa N, Tomura H, Okajima F. (2004) TDAG8 is a proton-sensing and psychosine-sensitive G-protein-coupled receptor. J. Biol. Chem., 279 (44): 45626-33. [PMID:15326175]


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How to cite this page

Anthony P. Davenport, Stephen Alexander, Joanna L. Sharman, Adam J. Pawson, Helen E. Benson, Amy E. Monaghan, Wen Chiy Liew, Chido Mpamhanga, Jim Battey, Richard V. Benya, Robert T. Jensen, Sadashiva Karnik, Evi Kostenis, Eliot Spindel, Laura Storjohann, Kalyan Tirupula, Tom I. Bonner, Richard Neubig, Jean-Philippe Pin, Michael Spedding, Anthony Harmar.
Class A Orphans: GPR65. Last modified on 14/03/2017. Accessed on 16/01/2019. IUPHAR/BPS Guide to PHARMACOLOGY, http://guidetoimmunopharmacology.org/GRAC/ObjectDisplayForward?objectId=113.