CD81 Gene

HGNC Family	CD molecules (CD), Tetraspanins (TSPAN)
Name	CD81 molecule
Description	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]
Summary	{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n CD81, a member of the tetraspanin family, plays pivotal roles in both pathogen entry and immune cell signaling. In the context of viral infection, several studies demonstrate that CD81 is an essential co‐receptor for hepatitis C virus (HCV) entry. CD81 expression on hepatocytes is required for successful infection by HCV pseudoparticles, and its blockade—either by specific antibodies or by expression of non‐human forms—strongly impairs viral uptake and subsequent infection, underscoring its critical function as an attachment and post‐binding entry factor."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "6"}]}, {"type": "t", "text": " Similarly, CD81 expression on hepatocytes has been shown to be indispensable for the infection of Plasmodium sporozoites, being required for the formation of the parasitophorous vacuole that supports parasite differentiation within liver cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In the immune system, CD81 is a key component of the multiprotein complex formed with CD19, CD21, and other molecules on mature B cells. This complex acts to lower the threshold for B cell activation via the B-cell receptor. Genetic studies in patients with immunodeficiency have revealed that mutations leading to CD81 deficiency result in impaired CD19 expression and defective B cell receptor signaling, thereby compromising memory B cell formation and antibody responses."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": " Moreover, disruption of cytoskeletal organization has been linked to alterations in B cell receptor nanocluster dynamics that require CD81 for optimal signaling, further supporting its role in fine-tuning tonic and inducible immune responses."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": "\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Matthew J Evans, Thomas von Hahn, Donna M Tscherne, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Claudin-1 is a hepatitis C virus co-receptor required for a late step in entry."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nature (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/nature05654"}], "href": "https://doi.org/10.1038/nature05654"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17325668"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17325668"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Alexander Ploss, Matthew J Evans, Valeriya A Gaysinskaya, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Human occludin is a hepatitis C virus entry factor required for infection of mouse cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nature (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/nature07684"}], "href": "https://doi.org/10.1038/nature07684"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19182773"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19182773"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Birke Bartosch, Alessandra Vitelli, Christelle Granier, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Cell entry of hepatitis C virus requires a set of co-receptors that include the CD81 tetraspanin and the SR-B1 scavenger receptor."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M305289200"}], "href": "https://doi.org/10.1074/jbc.M305289200"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12913001"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12913001"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Toshiro Moroishi, Tomoko Hayashi, Wei-Wei Pan, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The Hippo Pathway Kinases LATS1/2 Suppress Cancer Immunity."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cell (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.cell.2016.11.005"}], "href": "https://doi.org/10.1016/j.cell.2016.11.005"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27912060"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27912060"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Zhenyang Zhao, Yan Chen, Jian Wang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Age-related retinopathy in NRF2-deficient mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0019456"}], "href": "https://doi.org/10.1371/journal.pone.0019456"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21559389"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21559389"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Emmanuel G Cormier, Fay Tsamis, Francis Kajumo, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CD81 is an entry coreceptor for hepatitis C virus."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proc Natl Acad Sci U S A (2004)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1073/pnas.0402253101"}], "href": "https://doi.org/10.1073/pnas.0402253101"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "15123813"}], "href": "https://pubmed.ncbi.nlm.nih.gov/15123813"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "Olivier Silvie, Eric Rubinstein, Jean-François Franetich, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Hepatocyte CD81 is required for Plasmodium falciparum and Plasmodium yoelii sporozoite infectivity."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nat Med (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/nm808"}], "href": "https://doi.org/10.1038/nm808"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12483205"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12483205"}]}, {"type": "r", "ref": 8, "children": [{"type": "t", "text": "Menno C van Zelm, Ismail Reisli, Mirjam van der Burg, et al. "}, {"type": "b", "children": [{"type": "t", "text": "An antibody-deficiency syndrome due to mutations in the CD19 gene."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "N Engl J Med (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1056/NEJMoa051568"}], "href": "https://doi.org/10.1056/NEJMoa051568"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16672701"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16672701"}]}, {"type": "r", "ref": 9, "children": [{"type": "t", "text": "Menno C van Zelm, Julie Smet, Brigitte Adams, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CD81 gene defect in humans disrupts CD19 complex formation and leads to antibody deficiency."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Clin Invest (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1172/JCI39748"}], "href": "https://doi.org/10.1172/JCI39748"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20237408"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20237408"}]}, {"type": "r", "ref": 10, "children": [{"type": "t", "text": "Pieta K Mattila, Christoph Feest, David Depoil, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The actin and tetraspanin networks organize receptor nanoclusters to regulate B cell receptor-mediated signaling."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Immunity (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.immuni.2012.11.019"}], "href": "https://doi.org/10.1016/j.immuni.2012.11.019"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23499492"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23499492"}]}]}]}
Synonyms	CVID6, TAPA1, S5.7, TSPAN28
Proteins	CD81_HUMAN
NCBI Gene ID	975
API
Download Associations
Predicted Functions
Co-expressed Genes
Expression in Tissues and Cell Lines

Functional Associations

CD81 has 11,428 functional associations with biological entities spanning 9 categories (molecular profile, organism, disease, phenotype or trait, chemical, functional term, phrase or reference, structural feature, cell line, cell type or tissue, gene, protein or microRNA, sequence feature) extracted from 126 datasets.

Click the + buttons to view associations for CD81 from the datasets below.

If available, associations are ranked by standardized value

Harmonizome 3.0

CD81 Gene

Functional Associations

Please acknowledge the Harmonizome in your publications by citing the following reference(s):

	Dataset	Summary
	Achilles Cell Line Gene Essentiality Profiles	cell lines with fitness changed by CD81 gene knockdown relative to other cell lines from the Achilles Cell Line Gene Essentiality Profiles dataset.
	Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CD81 gene relative to other tissues from the Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles	tissues with high or low expression of CD81 gene relative to other tissues from the Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray	tissue samples with high or low expression of CD81 gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq	tissue samples with high or low expression of CD81 gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq dataset.
	Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CD81 gene relative to other tissues from the Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles dataset.
	BioGPS Cell Line Gene Expression Profiles	cell lines with high or low expression of CD81 gene relative to other cell lines from the BioGPS Cell Line Gene Expression Profiles dataset.
	BioGPS Human Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CD81 gene relative to other cell types and tissues from the BioGPS Human Cell Type and Tissue Gene Expression Profiles dataset.
	BioGPS Mouse Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CD81 gene relative to other cell types and tissues from the BioGPS Mouse Cell Type and Tissue Gene Expression Profiles dataset.
	CCLE Cell Line Gene CNV Profiles	cell lines with high or low copy number of CD81 gene relative to other cell lines from the CCLE Cell Line Gene CNV Profiles dataset.
	CCLE Cell Line Gene Expression Profiles	cell lines with high or low expression of CD81 gene relative to other cell lines from the CCLE Cell Line Gene Expression Profiles dataset.
	CCLE Cell Line Proteomics	Cell lines associated with CD81 protein from the CCLE Cell Line Proteomics dataset.
	CellMarker Gene-Cell Type Associations	cell types associated with CD81 gene from the CellMarker Gene-Cell Type Associations dataset.
	ChEA Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CD81 gene from the CHEA Transcription Factor Binding Site Profiles dataset.
	ChEA Transcription Factor Targets	transcription factors binding the promoter of CD81 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets dataset.
	ChEA Transcription Factor Targets 2022	transcription factors binding the promoter of CD81 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets 2022 dataset.
	ClinVar Gene-Phenotype Associations	phenotypes associated with CD81 gene from the curated ClinVar Gene-Phenotype Associations dataset.
	CMAP Signatures of Differentially Expressed Genes for Small Molecules	small molecule perturbations changing expression of CD81 gene from the CMAP Signatures of Differentially Expressed Genes for Small Molecules dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores	cellular components containing CD81 protein from the COMPARTMENTS Curated Protein Localization Evidence Scores dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores 2025	cellular components containing CD81 protein from the COMPARTMENTS Curated Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Experimental Protein Localization Evidence Scores	cellular components containing CD81 protein in low- or high-throughput protein localization assays from the COMPARTMENTS Experimental Protein Localization Evidence Scores dataset.
	COMPARTMENTS Experimental Protein Localization Evidence Scores 2025	cellular components containing CD81 protein in low- or high-throughput protein localization assays from the COMPARTMENTS Experimental Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores	cellular components co-occuring with CD81 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025	cellular components co-occuring with CD81 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025 dataset.
	CORUM Protein Complexes	protein complexs containing CD81 protein from the CORUM Protein Complexes dataset.
	COSMIC Cell Line Gene Mutation Profiles	cell lines with CD81 gene mutations from the COSMIC Cell Line Gene Mutation Profiles dataset.
	CTD Gene-Chemical Interactions	chemicals interacting with CD81 gene/protein from the curated CTD Gene-Chemical Interactions dataset.
	CTD Gene-Disease Associations	diseases associated with CD81 gene/protein from the curated CTD Gene-Disease Associations dataset.
	DeepCoverMOA Drug Mechanisms of Action	small molecule perturbations with high or low expression of CD81 protein relative to other small molecule perturbations from the DeepCoverMOA Drug Mechanisms of Action dataset.
	DepMap CRISPR Gene Dependency	cell lines with fitness changed by CD81 gene knockdown relative to other cell lines from the DepMap CRISPR Gene Dependency dataset.
	DISEASES Curated Gene-Disease Association Evidence Scores	diseases involving CD81 gene from the DISEASES Curated Gene-Disease Assocation Evidence Scores dataset.
	DISEASES Curated Gene-Disease Association Evidence Scores 2025	diseases involving CD81 gene from the DISEASES Curated Gene-Disease Association Evidence Scores 2025 dataset.
	DISEASES Experimental Gene-Disease Association Evidence Scores 2025	diseases associated with CD81 gene in GWAS datasets from the DISEASES Experimental Gene-Disease Assocation Evidence Scores 2025 dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores	diseases co-occuring with CD81 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores 2025	diseases co-occuring with CD81 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores 2025 dataset.
	DisGeNET Gene-Disease Associations	diseases associated with CD81 gene in GWAS and other genetic association datasets from the DisGeNET Gene-Disease Associations dataset.
	DisGeNET Gene-Phenotype Associations	phenotypes associated with CD81 gene in GWAS and other genetic association datasets from the DisGeNET Gene-Phenoptype Associations dataset.
	ENCODE Histone Modification Site Profiles	histone modification site profiles with high histone modification abundance at CD81 gene from the ENCODE Histone Modification Site Profiles dataset.
	ENCODE Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CD81 gene from the ENCODE Transcription Factor Binding Site Profiles dataset.
	ENCODE Transcription Factor Targets	transcription factors binding the promoter of CD81 gene in ChIP-seq datasets from the ENCODE Transcription Factor Targets dataset.