GPR18
N-arachidonyl glycine receptor
Also known as: GPR18_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- Q14330
- Gene
- GPR18
- Ensembl
- ENSG00000125245
- Chromosome
- 13
- Canonical length
- 331 aa
- Protein class
- G-protein coupled receptors, Predicted membrane proteins, Transporters
OverviewNCBI Gene
Enables G protein-coupled receptor activity. Predicted to be involved in G protein-coupled receptor signaling pathway. Predicted to act upstream of or within T cell differentiation; negative regulation of leukocyte chemotaxis; and negative regulation of tumor necrosis factor production. Predicted to be located in membrane. Predicted to be active in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
331 residues, UniProt reviewed canonical sequence.
>Q14330|GPR18
1 MITLNNQDQP VPFNSSHPDE YKIAALVFYS CIFIIGLFVN ITALWVFSCT TKKRTTVTIY
61 MMNVALVDLI FIMTLPFRMF YYAKDEWPFG EYFCQILGAL TVFYPSIALW LLAFISADRY
121 MAIVQPKYAK ELKNTCKAVL ACVGVWIMTL TTTTPLLLLY KDPDKDSTPA TCLKISDIIY
181 LKAVNVLNLT RLTFFFLIPL FIMIGCYLVI IHNLLHGRTS KLKPKVKEKS IRIIITLLVQ
241 VLVCFMPFHI CFAFLMLGTG ENSYNPWGAF TTFLMNLSTC LDVILYYIVS KQFQARVISV
301 MLYRNYLRSM RRKSFRSGSL RSLSNINSEM LLocalizationUniProt · AlphaFold · HPA
Whether an antibody against GPR18 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.
- Antibody reachability
- Cell surface
- Secreted
- No
- Transmembrane segments
- 7
- Mean surface accessibility (rSASA)
- 0.3
- Highest tissue expression
- 36 nTPM
Expression across tissuesHPA
Tissue
- lymph node: 36 nTPM
- tonsil: 30 nTPM
- testis: 12 nTPM
- appendix: 12 nTPM
- spleen: 9.9 nTPM
- bone marrow: 9.1 nTPM
Single-cell type
- late spermatids: 301 nCPM
- early spermatids: 232 nCPM
- cardiomyocytes: 67 nCPM
- b-cells: 58 nCPM
- t-cells: 32 nCPM
- nk-cells: 31 nCPM
Immune cell
- memory B-cell: 66 nTPM
- naive B-cell: 54 nTPM
- NK-cell: 53 nTPM
- naive CD4 T-cell: 42 nTPM
- MAIT T-cell: 41 nTPM
- naive CD8 T-cell: 39 nTPM
Brain region
- choroid plexus: 6 nTPM
- cerebellum: 5.4 nTPM
- medulla oblongata: 5.3 nTPM
- cerebral cortex: 4.8 nTPM
- white matter: 4.7 nTPM
- thalamus: 4.6 nTPM
Genetic constraint and essentialitygnomAD · DepMap
Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.
- gnomAD LOEUF (loss-of-function intolerance)
- 1.8
- gnomAD pLI
- 0
- gnomAD missense Z
- 0.42
- DepMap mean gene effect
- -0.02
- DepMap dependency class
- selective
Cancer expressionTCGA
Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).
OntologyGO
Biological processes
- CD8-positive, gamma-delta intraepithelial T cell differentiation
- G protein-coupled receptor signaling pathway
- negative regulation of leukocyte chemotaxis
- negative regulation of tumor necrosis factor production
- CD8-positive, alpha-beta intraepithelial T cell differentiation
Molecular functions
Cellular components
Protein domainsUniProt · Pfam · InterPro
- G protein-coupled receptor, rhodopsin-like
- GPCR, rhodopsin-like, 7TM
- 7 transmembrane receptor (rhodopsin family)
- G protein-coupled receptor 18 orphan
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads GPR18 as an antibody target. Whether an autoantibody or antibody against GPR18 could matter depends on whether native GPR18 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
GPR18 is annotated at the cell surface, where native GPR18 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.
Annotation status
The present source text does not explicitly label GPR18 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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