Seroatlas · Human Serome Atlas

CD81

CD81 antigen

Also known as: CD81_HUMAN, TAPA-1, TAPA1, TSPAN28

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
P60033
Gene
CD81
Ensembl
ENSG00000110651
Chromosome
11
Canonical length
236 aa
Protein class
CD markers, Disease related genes, Human disease related genes, Plasma proteins, Potential drug targets, Predicted membrane proteins, Transporters
Subcellular location
Plasma membrane,Cytosol
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. The proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. This encoded protein is a cell surface glycoprotein that is known to complex with integrins. This protein appears to promote muscle cell fusion and support myotube maintenance. Also it may be involved in signal transduction. This gene is localized in the tumor-suppressor gene region and thus it is a candidate gene for malignancies. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2014]

Canonical amino-acid sequenceUniProt

236 residues, UniProt reviewed canonical sequence.

>P60033|CD81
     1  MGVEGCTKCI KYLLFVFNFV FWLAGGVILG VALWLRHDPQ TTNLLYLELG DKPAPNTFYV
    61  GIYILIAVGA VMMFVGFLGC YGAIQESQCL LGTFFTCLVI LFACEVAAGI WGFVNKDQIA
   121  KDVKQFYDQA LQQAVVDDDA NNAKAVVKTF HETLDCCGSS TLTALTTSVL KNNLCPSGSN
   181  IISNLFKEDC HQKIDDLFSG KLYLIGIAAI VVAVIMIFEM ILSMVLCCGI RNSSVY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CD81 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
4
Mean surface accessibility (rSASA)
0.31
Highest tissue expression
1,494 nTPM

Expression across tissuesHPA

Tissue

  • seminal vesicle: 1,494 nTPM
  • endometrium: 1,244 nTPM
  • liver: 1,133 nTPM
  • blood vessel: 1,003 nTPM
  • cervix: 939 nTPM
  • colon: 928 nTPM

Single-cell type

  • breast lactating cells: 1,124 nCPM
  • smooth muscle cells: 1,085 nCPM
  • fallopian secretory cells: 865 nCPM
  • epididymal principal cells: 853 nCPM
  • fallopian tube ciliated cells: 817 nCPM
  • endometrial stromal cells: 765 nCPM

Immune cell

  • memory B-cell: 149 nTPM
  • naive B-cell: 138 nTPM
  • MAIT T-cell: 34 nTPM
  • memory CD8 T-cell: 33 nTPM
  • eosinophil: 23 nTPM
  • gdT-cell: 21 nTPM

Brain region

  • white matter: 886 nTPM
  • spinal cord: 844 nTPM
  • medulla oblongata: 765 nTPM
  • thalamus: 762 nTPM
  • midbrain: 721 nTPM
  • hypothalamus: 672 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CD81.

Disease | AllUniProt

Conditions CD81 is implicated in, by any mechanism.

  • Immunodeficiency, common variable, 6 (CVID6) MIM:613496

Disease | GeneticClinVar

1 pathogenic / likely-pathogenic of 327 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • Immunodeficiency, common variable, 6

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)
0.38
gnomAD pLI
0.92
gnomAD missense Z
0.81
DepMap mean gene effect
0.06
DepMap dependency class
selective

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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CD81 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CD81 as an antibody target. Whether an autoantibody or antibody against CD81 could matter depends on whether native CD81 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CD81 is annotated at the cell surface, where native CD81 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 CD81 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CD81. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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