HCAR2
Hydroxycarboxylic acid receptor 2
Also known as: GPR109A, HCA2, HCAR2_HUMAN, HM74A, NIACR1, Puma-g, PUMAG
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- Q8TDS4
- Gene
- HCAR2
- Ensembl
- ENSG00000182782
- Chromosome
- 12
- Canonical length
- 363 aa
- Protein class
- FDA approved drug targets, G-protein coupled receptors, Predicted membrane proteins
- Subcellular location
- Cell Junctions
OverviewNCBI Gene
Predicted to enable nicotinic acid receptor activity. Involved in neutrophil apoptotic process and positive regulation of neutrophil apoptotic process. Located in cell junction and plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
363 residues, UniProt reviewed canonical sequence.
>Q8TDS4|HCAR2
1 MNRHHLQDHF LEIDKKNCCV FRDDFIVKVL PPVLGLEFIF GLLGNGLALW IFCFHLKSWK
61 SSRIFLFNLA VADFLLIICL PFLMDNYVRR WDWKFGDIPC RLMLFMLAMN RQGSIIFLTV
121 VAVDRYFRVV HPHHALNKIS NRTAAIISCL LWGITIGLTV HLLKKKMPIQ NGGANLCSSF
181 SICHTFQWHE AMFLLEFFLP LGIILFCSAR IIWSLRQRQM DRHAKIKRAI TFIMVVAIVF
241 VICFLPSVVV RIRIFWLLHT SGTQNCEVYR SVDLAFFITL SFTYMNSMLD PVVYYFSSPS
301 FPNFFSTLIN RCLQRKMTGE PDNNRSTSVE LTGDPNKTRG APEALMANSG EPWSPSYLGP
361 TSPLocalizationUniProt · AlphaFold · HPA
Whether an antibody against HCAR2 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)
- 0.33
- Highest tissue expression
- 39 nTPM
Expression across tissuesHPA
Tissue
- esophagus: 39 nTPM
- skin: 29 nTPM
- spleen: 24 nTPM
- bone marrow: 21 nTPM
- adipose tissue: 21 nTPM
- seminal vesicle: 14 nTPM
Single-cell type
- epididymal basal cells: 445 nCPM
- esophageal apical cells: 442 nCPM
- neutrophils: 106 nCPM
- ocular epithelial cells: 98 nCPM
- respiratory secretory cells: 79 nCPM
- respiratory basal cells: 73 nCPM
Immune cell
- neutrophil: 177 nTPM
- basophil: 39 nTPM
- non-classical monocyte: 24 nTPM
- intermediate monocyte: 5.3 nTPM
- eosinophil: 2.6 nTPM
- classical monocyte: 2.5 nTPM
Brain region
- cerebral cortex: 12 nTPM
- pons: 2.5 nTPM
- hippocampal formation: 0.5 nTPM
- choroid plexus: 0.4 nTPM
- thalamus: 0.4 nTPM
- basal ganglia: 0.3 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)
- 1.63
- gnomAD pLI
- 0
- gnomAD missense Z
- -0.2
- DepMap mean gene effect
- 0.14
- DepMap dependency class
- none
Cancer expressionTCGA
Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).
OntologyGO
Biological processes
- G protein-coupled receptor signaling pathway
- negative regulation of lipid catabolic process
- neutrophil apoptotic process
- positive regulation of adiponectin secretion
- positive regulation of neutrophil apoptotic process
Molecular functions
Cellular components
Protein domainsUniProt · Pfam · InterPro
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads HCAR2 as an antibody target. Whether an autoantibody or antibody against HCAR2 could matter depends on whether native HCAR2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
HCAR2 is annotated at the cell surface, where native HCAR2 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 HCAR2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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