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Gene Review

CD81  -  CD81 molecule

Homo sapiens

Synonyms: 26 kDa cell surface protein TAPA-1, CD81 antigen, CVID6, S5.7, TAPA-1, ...
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Disease relevance of CD81

  • Like CD81, several tetraspanins are involved in cell adhesion, motility, and metastasis, as well as cell activation and signal transduction [1].
  • HTLV-1 MA also interacted with the inner loop of CD81 [2].
  • To further characterize the major proteins present in a typical TM4SF protein complex, we raised monoclonal antibodies against proteins co-immunoprecipitated with CD81 from MDA-MB-435 breast cancer cells [3].
  • CD81 is required for hepatitis C virus glycoprotein-mediated viral infection [4].
  • CD81 is required for HIV-HCV pseudotype infection since (i) a monoclonal antibody specific for CD81 inhibited infection of susceptible target cells and (ii) silencing of CD81 expression in Huh-7.5 hepatoma cells by small interfering RNAs inhibited HIV-HCV pseudotype infection [4].

Psychiatry related information on CD81


High impact information on CD81


Chemical compound and disease context of CD81


Biological context of CD81


Anatomical context of CD81

  • Finally, anti-CD9 and anti-CD81 monoclonal antibodies triggered apoptotic degeneration of C2C12 cell myotubes after they were formed [15].
  • Ectopic expression of CD9 caused a four- to eightfold increase in RD cell syncytia formation, whereas anti-CD9 and anti-CD81 antibodies markedly delayed RD syncytia formation [15].
  • In summary, TM4SF proteins such as CD9 and CD81 appear to promote muscle cell fusion and support myotube maintenance [15].
  • Enhanced signaling is due in part to the ability of the CD19/CD21/CD81 complex to stabilize the BCR in sphingolipid- and cholesterol-rich membrane microdomains termed lipid rafts [16].
  • Transmembrane-4-superfamily proteins CD151 and CD81 associate with alpha 3 beta 1 integrin, and selectively contribute to alpha 3 beta 1-dependent neurite outgrowth [17].

Associations of CD81 with chemical compounds

  • Anti-alpha 4 integrin mAb also coprecipitated CD81 from the alpha 4 beta 7-positive B cell line RPMI 8866 [18].
  • We have examined the role of CD81 in HCV glycoprotein-dependent entry by using a recently developed retroviral pseudotyping system [4].
  • On mAb binding, CD38 translocates to the membrane lipid microdomains, as shown by a colocalization with the GM1 ganglioside and with CD81, a raft-resident protein [19].
  • We have generated a series of CD81 cysteine mutants to identify palmitoylated intracellular motifs of CD81, and reveal palmitoylation on the N- and C-terminal tails as well as the intracellular loop between transmembrane domains 2 and 3 [20].
  • Here, we show that CD81 clustering stimulates ERK/MAPKinase activity and tyrosine phosphorylation of the adapter protein Shc in Huh7 cancer cells [21].

Physical interactions of CD81

  • Here, we examine whether coligation of the B cell Ag receptor (BCR) with the complement (C3)-binding CD21/CD19/CD81 costimulatory complex can enhance the escape of human B cells from Fas-induced death [14].
  • CD9P-1 was also shown to form separate complexes with CD81 and with an unidentified 175-kDa molecule [22].
  • Hepatitis C virus (HCV) or HCV-low-density lipoprotein (LDL) complexes interact with the LDL receptor (LDLr) and the HCV envelope glycoprotein E2 interacts with CD81 in vitro [23].
  • Cross-linking CD81 is also shown to be costimulatory with signaling through the TCR/CD3 complex inducing interleukin 2-dependent thymocyte proliferation [24].

Co-localisations of CD81


Regulatory relationships of CD81


Other interactions of CD81

  • In nonstringent detergent, NAG-2 protein was co-immunoprecipitated with other TM4SF members (CD9 and CD81) and integrins (alpha3beta1 and alpha6beta1) [3].
  • Thus, association of HTLV-1 Gag with tetraspanin-enriched microdomains is mediated by the inner loops of CD81 and CD82 [2].
  • Also, cross-linking experiments established that alpha 3 beta 1/CD81, alpha 3 beta 1/CD9, and alpha 3 beta 1/CD63 associations occur on the surface of intact cells and suggested that a critical interaction site is located within extracellular domains [30].
  • The palmitoylation of CD9 did not influence the partition in detergent-resistant membranes but contributed to the interaction with CD81 and CD53 [31].
  • Here, we investigated whether altered CCR5 expression in hepatitis C results from interactions of CD81 with the HCV E2 protein [32].

Analytical, diagnostic and therapeutic context of CD81


  1. CD81 (TAPA-1): a molecule involved in signal transduction and cell adhesion in the immune system. Levy, S., Todd, S.C., Maecker, H.T. Annu. Rev. Immunol. (1998) [Pubmed]
  2. The Inner Loop of Tetraspanins CD82 and CD81 Mediates Interactions with Human T Cell Lymphotrophic Virus Type 1 Gag Protein. Mazurov, D., Heidecker, G., Derse, D. J. Biol. Chem. (2007) [Pubmed]
  3. NAG-2, a novel transmembrane-4 superfamily (TM4SF) protein that complexes with integrins and other TM4SF proteins. Tachibana, I., Bodorova, J., Berditchevski, F., Zutter, M.M., Hemler, M.E. J. Biol. Chem. (1997) [Pubmed]
  4. CD81 is required for hepatitis C virus glycoprotein-mediated viral infection. Zhang, J., Randall, G., Higginbottom, A., Monk, P., Rice, C.M., McKeating, J.A. J. Virol. (2004) [Pubmed]
  5. Binding of hepatitis C virus E2 glycoprotein to CD81 does not correlate with species permissiveness to infection. Meola, A., Sbardellati, A., Bruni Ercole, B., Cerretani, M., Pezzanera, M., Ceccacci, A., Vitelli, A., Levy, S., Nicosia, A., Traboni, C., McKeating, J., Scarselli, E. J. Virol. (2000) [Pubmed]
  6. In vivo gene silencing of CD81 by lentiviral expression of small interference RNAs suppresses cocaine-induced behaviour. Bahi, A., Boyer, F., Kolira, M., Dreyer, J.L. J. Neurochem. (2005) [Pubmed]
  7. Low density lipoprotein receptor transcripts correlates with liver hepatitis C virus RNA in patients with alcohol consumption. Carrière, M., Rosenberg, A.R., Conti, F., Chouzenoux, S., Terris, B., Sogni, P., Soubrane, O., Calmus, Y., Podevin, P. J. Viral Hepat. (2006) [Pubmed]
  8. The CD19/CR2/TAPA-1 complex of B lymphocytes: linking natural to acquired immunity. Fearon, D.T., Carter, R.H. Annu. Rev. Immunol. (1995) [Pubmed]
  9. Dynamics of CD81 expression on lymphocyte subsets during interferon-alpha-based antiviral treatment of patients with chronic hepatitis C. Kronenberger, B., Herrmann, E., Hofmann, W.P., Wedemeyer, H., Sester, M., Mihm, U., Ghaliai, T., Zeuzem, S., Sarrazin, C. J. Leukoc. Biol. (2006) [Pubmed]
  10. The CD19/CD21 signal transduction complex of B lymphocytes. Tedder, T.F., Zhou, L.J., Engel, P. Immunol. Today (1994) [Pubmed]
  11. Importance of the major extracellular domain of CD9 and the epidermal growth factor (EGF)-like domain of heparin-binding EGF-like growth factor for up-regulation of binding and activity. Nakamura, K., Mitamura, T., Takahashi, T., Kobayashi, T., Mekada, E. J. Biol. Chem. (2000) [Pubmed]
  12. Identification of a lactoferrin-derived peptide possessing binding activity to hepatitis C virus E2 envelope protein. Nozaki, A., Ikeda, M., Naganuma, A., Nakamura, T., Inudoh, M., Tanaka, K., Kato, N. J. Biol. Chem. (2003) [Pubmed]
  13. Tetraspanin CD82 attenuates cellular morphogenesis through down-regulating integrin alpha6-mediated cell adhesion. He, B., Liu, L., Cook, G.A., Grgurevich, S., Jennings, L.K., Zhang, X.A. J. Biol. Chem. (2005) [Pubmed]
  14. Role of complement-binding CD21/CD19/CD81 in enhancing human B cell protection from Fas-mediated apoptosis. Mongini, P.K., Jackson, A.E., Tolani, S., Fattah, R.J., Inman, J.K. J. Immunol. (2003) [Pubmed]
  15. Role of transmembrane 4 superfamily (TM4SF) proteins CD9 and CD81 in muscle cell fusion and myotube maintenance. Tachibana, I., Hemler, M.E. J. Cell Biol. (1999) [Pubmed]
  16. B cell signaling is regulated by induced palmitoylation of CD81. Cherukuri, A., Carter, R.H., Brooks, S., Bornmann, W., Finn, R., Dowd, C.S., Pierce, S.K. J. Biol. Chem. (2004) [Pubmed]
  17. Transmembrane-4-superfamily proteins CD151 and CD81 associate with alpha 3 beta 1 integrin, and selectively contribute to alpha 3 beta 1-dependent neurite outgrowth. Stipp, C.S., Hemler, M.E. J. Cell. Sci. (2000) [Pubmed]
  18. Transmembrane-4 superfamily proteins CD81 (TAPA-1), CD82, CD63, and CD53 specifically associated with integrin alpha 4 beta 1 (CD49d/CD29). Mannion, B.A., Berditchevski, F., Kraeft, S.K., Chen, L.B., Hemler, M.E. J. Immunol. (1996) [Pubmed]
  19. CD38 is a signaling molecule in B-cell chronic lymphocytic leukemia cells. Deaglio, S., Capobianco, A., Bergui, L., Dürig, J., Morabito, F., Dührsen, U., Malavasi, F. Blood (2003) [Pubmed]
  20. CD81 associates with 14-3-3 in a redox-regulated palmitoylation-dependent manner. Clark, K.L., Oelke, A., Johnson, M.E., Eilert, K.D., Simpson, P.C., Todd, S.C. J. Biol. Chem. (2004) [Pubmed]
  21. Tetraspanin CD81 is linked to ERK/MAPKinase signaling by Shc in liver tumor cells. Carloni, V., Mazzocca, A., Ravichandran, K.S. Oncogene (2004) [Pubmed]
  22. The major CD9 and CD81 molecular partner. Identification and characterization of the complexes. Charrin, S., Le Naour, F., Oualid, M., Billard, M., Faure, G., Hanash, S.M., Boucheix, C., Rubinstein, E. J. Biol. Chem. (2001) [Pubmed]
  23. Characterization of hepatitis C virus (HCV) and HCV E2 interactions with CD81 and the low-density lipoprotein receptor. Wünschmann, S., Medh, J.D., Klinzmann, D., Schmidt, W.N., Stapleton, J.T. J. Virol. (2000) [Pubmed]
  24. CD81 expressed on human thymocytes mediates integrin activation and interleukin 2-dependent proliferation. Todd, S.C., Lipps, S.G., Crisa, L., Salomon, D.R., Tsoukas, C.D. J. Exp. Med. (1996) [Pubmed]
  25. Molecular analyses of the association of CD4 with two members of the transmembrane 4 superfamily, CD81 and CD82. Imai, T., Kakizaki, M., Nishimura, M., Yoshie, O. J. Immunol. (1995) [Pubmed]
  26. Association of low-density lipoprotein receptor polymorphisms and outcome of hepatitis C infection. Hennig, B.J., Hellier, S., Frodsham, A.J., Zhang, L., Klenerman, P., Knapp, S., Wright, M., Thomas, H.C., Thursz, M., Hill, A.V. Genes Immun. (2002) [Pubmed]
  27. Cutting edge: dynamic redistribution of tetraspanin CD81 at the central zone of the immune synapse in both T lymphocytes and APC. Mittelbrunn, M., Yáñez-Mó, M., Sancho, D., Ursa, A., Sánchez-Madrid, F. J. Immunol. (2002) [Pubmed]
  28. Hepatitis C virus E2-CD81 interaction induces hypermutation of the immunoglobulin gene in B cells. Machida, K., Cheng, K.T., Pavio, N., Sung, V.M., Lai, M.M. J. Virol. (2005) [Pubmed]
  29. The hepatitis C envelope 2 protein inhibits LFA-1-transduced protein kinase C signaling for T-lymphocyte migration. Volkov, Y., Long, A., Freeley, M., Golden-Mason, L., O'Farrelly, C., Murphy, A., Kelleher, D. Gastroenterology (2006) [Pubmed]
  30. Characterization of novel complexes on the cell surface between integrins and proteins with 4 transmembrane domains (TM4 proteins). Berditchevski, F., Zutter, M.M., Hemler, M.E. Mol. Biol. Cell (1996) [Pubmed]
  31. Differential stability of tetraspanin/tetraspanin interactions: role of palmitoylation. Charrin, S., Manié, S., Oualid, M., Billard, M., Boucheix, C., Rubinstein, E. FEBS Lett. (2002) [Pubmed]
  32. Binding of HCV E2 to CD81 induces RANTES secretion and internalization of CC chemokine receptor 5. Nattermann, J., Nischalke, H.D., Feldmann, G., Ahlenstiel, G., Sauerbruch, T., Spengler, U. J. Viral Hepat. (2004) [Pubmed]
  33. Characterization of hepatitis C virus E2 glycoprotein interaction with a putative cellular receptor, CD81. Flint, M., Maidens, C., Loomis-Price, L.D., Shotton, C., Dubuisson, J., Monk, P., Higginbottom, A., Levy, S., McKeating, J.A. J. Virol. (1999) [Pubmed]
  34. Selective tetraspan-integrin complexes (CD81/alpha4beta1, CD151/alpha3beta1, CD151/alpha6beta1) under conditions disrupting tetraspan interactions. Serru, V., Le Naour, F., Billard, M., Azorsa, D.O., Lanza, F., Boucheix, C., Rubinstein, E. Biochem. J. (1999) [Pubmed]
  35. HIV-1 trafficking to the dendritic cell-T-cell infectious synapse uses a pathway of tetraspanin sorting to the immunological synapse. Garcia, E., Pion, M., Pelchen-Matthews, A., Collinson, L., Arrighi, J.F., Blot, G., Leuba, F., Escola, J.M., Demaurex, N., Marsh, M., Piguet, V. Traffic (2005) [Pubmed]
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