GPR81

Hydroxycarboxylic acid receptor 1

Identifiers

HCAR1 ; GPR104; GPR81; HCA1; LACR1; TA-GPCR; TAGPCR

External IDs

OMIM: 606923 MGI: 2441671 HomoloGene: 13060 IUPHAR: 311 ChEMBL: 1075101 GeneCards: HCAR1 Gene

Gene ontology
Molecular function	• G-protein coupled receptor activity
Cellular component	• plasma membrane • integral component of membrane
Biological process	• G-protein coupled receptor signaling pathway • response to estradiol
Sources: Amigo / QuickGO

RNA expression pattern

More reference expression data

Orthologs

Species

Human

Mouse

RefSeq (mRNA)

RefSeq (protein)

Location (UCSC)

Chr 12:
123.1 – 123.22 Mb

Chr 5:
123.88 – 123.88 Mb

PubMed search

G protein-coupled receptor 81, also known as GPR81, is a protein that in humans is encoded by the GPR81 gene.^[1]^[2]

G protein-coupled receptors (GPCRs, or GPRs), such as GPR81, contain 7 transmembrane domains and transduce extracellular signals through heterotrimeric G proteins.^[1]

Lactate activates the GPR81 receptor which in turn inhibits lipolysis in fat cells.^[3]^[4]

References

↑ 1.0 1.1 "Entrez Gene: GPR81 G protein-coupled receptor 81".
↑ Lee DK, Nguyen T, Lynch KR, Cheng R, Vanti WB, Arkhitko O, Lewis T, Evans JF, George SR, O'Dowd BF (September 2001). "Discovery and mapping of ten novel G protein-coupled receptor genes". Gene 275 (1): 83–91. doi:10.1016/S0378-1119(01)00651-5. PMID 11574155.
↑ Liu C, Wu J, Zhu J, Kuei C, Yu J, Shelton J, Sutton SW, Li X, Yun SJ, Mirzadegan T, Mazur C, Kamme F, Lovenberg TW (January 2009). "Lactate inhibits lipolysis in fat cells through activation of an orphan G-protein-coupled receptor, GPR81". J. Biol. Chem. 284 (5): 2811–22. doi:10.1074/jbc.M806409200. PMID 19047060.
↑ Cai TQ, Ren N, Jin L, Cheng K, Kash S, Chen R, Wright SD, Taggart AK, Waters MG (December 2008). "Role of GPR81 in lactate-mediated reduction of adipose lipolysis". Biochem. Biophys. Res. Commun. 377 (3): 987–91. doi:10.1016/j.bbrc.2008.10.088. PMID 18952058.

Takeda S, Kadowaki S, Haga T et al. (2002). "Identification of G protein-coupled receptor genes from the human genome sequence.". FEBS Lett. 520 (1-3): 97–101. doi:10.1016/S0014-5793(02)02775-8. PMID 12044878.
Strausberg RL, Feingold EA, Grouse LH et al. (2003). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932.
Mao M, Biery MC, Kobayashi SV et al. (2005). "T lymphocyte activation gene identification by coregulated expression on DNA microarrays.". Genomics 83 (6): 989–99. doi:10.1016/j.ygeno.2003.12.019. PMID 15177553.
Gerhard DS, Wagner L, Feingold EA et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMC 528928. PMID 15489334.

Cell surface receptor: G protein-coupled receptors

Class A: Rhodopsin like

Neurotransmitter

Adrenergic	α1 (A B D) α2 (A B C) β1 β2 β3

Purinergic	Adenosine (A1 A2A A2B A3) P2Y (1 2 4 5 6 8 9 10 11 12 13 14)

Serotonin	(all but 5-HT3) 5-HT1 (A B D E F) 5-HT2 (A B C) 5-HT (4 5A 6 7)

Other	Acetylcholine (M1 M2 M3 M4 M5) Dopamine (D1 D2 D3 D4 D5) Histamine (H1 H2 H3 H4) Melatonin (1A 1B 1C) TAAR (1 2 3 5 6 8 9)

Metabolites and
signaling molecules

Eicosanoid	CysLT (1 2) LTB4 (1 2) FPRL1 OXE Prostaglandin (DP (1 2), EP (1 2 3 4), FP) Prostacyclin Thromboxane

Other	Bile acid Cannabinoid (CB1 CB2, GPR (18 55 119)) EBI2 Estrogen Free fatty acid (1 2 3 4) Lactate Lysophosphatidic acid (1 2 3 4 5 6) Lysophospholipid (1 2 3 4 5 6 7 8) Niacin (1 2) Oxoglutarate PAF Sphingosine-1-phosphate (1 2 3 4 5) Succinate

Peptide

Neuropeptide	B/W (1 2) FF (1 2) S Y (1 2 4 5) Neuromedin (B U (1 2)) Neurotensin (1 2)

Other	Anaphylatoxin (C3a C5a) Angiotensin (1 2) Apelin Bombesin (BRS3 GRPR NMBR) Bradykinin (B1 B2) Chemokine Cholecystokinin (A B) Endothelin (A B) Formyl peptide (1 2 3) FSH Galanin (1 2 3) GHB receptor Gonadotropin-releasing hormone (1 2) Ghrelin Kisspeptin Luteinizing hormone/choriogonadotropin MAS (1 1L D E F G X1 X2 X3 X4) Melanocortin (1 2 3 4 5) MCHR (1 2) Motilin Opioid (Delta Kappa Mu Nociceptin & Zeta, but not Sigma) Orexin (1 2) Oxytocin Prokineticin (1 2) Prolactin-releasing peptide Relaxin (1 2 3 4) Somatostatin (1 2 3 4 5) Tachykinin (1 2 3) Thyrotropin Thyrotropin-releasing hormone Urotensin-II Vasopressin (1A 1B 2)

Miscellaneous

Orphan	GPR (1 3 4 6 12 15 17 18 19 20 21 22 23 25 26 27 31 32 33 34 35 37 39 42 44 45 50 52 55 61 62 63 65 68 75 77 78 81 82 83 84 85 87 88 92 101 103 109A 109B 119 120 132 135 137B 139 141 142 146 148 149 150 151 152 153 160 161 162 171 173 174 176 177 182 183)

Other	Adrenomedullin Olfactory Opsin (3 4 5 1LW 1MW 1SW RGR RRH) Protease-activated (1 2 3 4) SREB (1 2 3)

Class B: Secretin like

Orphan	GPR (56 64 97 98 110 111 112 113 114 115 116 123 124 125 126 128 133 143 144 155 157)

Adhesion	ADGRG (1 2 3 4 5 6 7)

Other	Brain-specific angiogenesis inhibitor (1 2 3) Cadherin (1 2 3) Calcitonin CALCRL CD97 Corticotropin-releasing hormone (1 2) EMR (1 2 3) Glucagon (GR GIPR GLP1R GLP2R) Growth hormone releasing hormone PACAPR1 GPR Latrophilin (1 2 3 ELTD1) Methuselah-like proteins Parathyroid hormone (1 2) Secretin Vasoactive intestinal peptide (1 2)

Class C: Metabotropic glutamate / pheromone

Taste	TAS1R (1 2 3) TAS2R (1 3 4 5 7 8 9 10 13 14 16 19 20 30 31 38 39 40 41 42 43 45 46 50 60)

Other	Calcium-sensing receptor GABA B (1 2) Glutamate receptor (Metabotropic glutamate (1 2 3 4 5 6 7 8)) GPRC6A GPR (156 158 179) RAIG (1 2 3 4)

Class F: Frizzled / Smoothened

Frizzled	Frizzled (1 2 3 4 5 6 7 8 9 10)

Smoothened	Smoothened

Index of signal transduction

Description	Intercellular neuropeptides growth factors cytokines hormones Cell surface receptors ligand-gated enzyme-linked G protein-coupled immunoglobulin superfamily integrins neuropeptide growth factor cytokine Intracellular adaptor proteins GTP-binding MAP kinase Calcium signaling Lipid signaling Pathways hedgehog Wnt TGF beta MAPK ERK notch JAK-STAT apoptosis hippo TLR

GPR81

References

Further reading