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RefSeq (mRNA)



RefSeq (protein)



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CD9 antigen is a protein that in humans is encoded by the CD9 gene.[1]


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.

CD9 is a cell surface glycoprotein that is known to complex with integrins and other transmembrane 4 superfamily proteins. CD9 is found on the surface of exosomes[2][3] and it can modulate cell adhesion and migration and also trigger platelet activation and aggregation. In addition, the protein appears to promote muscle cell fusion and support myotube maintenance.[4] This protein also seems to be a key part in the egg-sperm fusion during mammalian fertilization. While oocytes are ovulated, CD9-deficient oocytes are not properly fused with sperm upon fertilization.[5] CD9 is located in the microvillar membrane of the oocytes and also appears to intervene in maintaining the normal shape of oocyte microvilli.[6]


CD9 has been shown to interact with:

See also


  1. Katz F, Povey S, Parkar M, Schneider C, Sutherland R, Stanley K, Solomon E, Greaves M (March 1984). "Chromosome assignment of monoclonal antibody-defined determinants on human leukemic cells". Eur J Immunol. 13 (12): 1008–1013. doi:10.1002/eji.1830131211. PMID 6198179.
  2. Le Mercier I, Lines JL, Noelle RJ (May 2010). "Exosome secreted by MSC reduces myocardial ischemia/reperfusion injury". Stem Cell Research. 4 (3). doi:10.1016/j.scr.2009.12.003. PMID 20138817.
  3. Sumiyoshi N, Ishitobi H, Miyaki S, Miyado K, Adachi N, Ochi M (October 2016). "The role of tetraspanin CD9 in osteoarthritis using three different mouse models". Biomedical Research. 37 (5). doi:10.2220/biomedres.37.283. PMID 27784871.
  4. "Entrez Gene: CD9 CD9 molecule".
  5. Le Naour F, Rubinstein E, Jasmin C, Prenant M, Boucheix C (2000). "Severely Reduced Female Fertility in CD9-Deficient Mice". Science. 287 (5451): 319–321. doi:10.1126/science.287.5451.319. PMID 10634790.
  6. Runge KE, Evans JE, He ZY, Gupta S, McDonald KL, Stahlberg H, Primakoff P, Myles DG (2007). "Oocyte CD9 is enriched on the microvillar membrane and required for normal microvillar shape and distribution". Developmental Biology. 304 (1): 317–325. doi:10.1016/j.ydbio.2006.12.041. PMID 17239847.
  7. Anzai N, Lee Y, Youn BS, Fukuda S, Kim YJ, Mantel C, Akashi M, Broxmeyer HE (June 2002). "C-kit associated with the transmembrane 4 superfamily proteins constitutes a functionally distinct subunit in human hematopoietic progenitors". Blood. 99 (12): 4413–21. doi:10.1182/blood.v99.12.4413. PMID 12036870.
  8. 8.0 8.1 Radford KJ, Thorne RF, Hersey P (May 1996). "CD63 associates with transmembrane 4 superfamily members, CD9 and CD81, and with beta 1 integrins in human melanoma". Biochem. Biophys. Res. Commun. 222 (1): 13–8. doi:10.1006/bbrc.1996.0690. PMID 8630057.
  9. Mazzocca A, Carloni V, Sciammetta S, Cordella C, Pantaleo P, Caldini A, Gentilini P, Pinzani M (September 2002). "Expression of transmembrane 4 superfamily (TM4SF) proteins and their role in hepatic stellate cell motility and wound healing migration". J. Hepatol. 37 (3): 322–30. doi:10.1016/s0168-8278(02)00175-7. PMID 12175627.
  10. Lozahic S, Christiansen D, Manié S, Gerlier D, Billard M, Boucheix C, Rubinstein E (March 2000). "CD46 (membrane cofactor protein) associates with multiple beta1 integrins and tetraspans". Eur. J. Immunol. 30 (3): 900–7. doi:10.1002/1521-4141(200003)30:3<900::AID-IMMU900>3.0.CO;2-X. PMID 10741407.
  11. Park KR, Inoue T, Ueda M, Hirano T, Higuchi T, Maeda M, Konishi I, Fujiwara H, Fujii S (March 2000). "CD9 is expressed on human endometrial epithelial cells in association with integrins alpha(6), alpha(3) and beta(1)". Mol. Hum. Reprod. 6 (3): 252–7. doi:10.1093/molehr/6.3.252. PMID 10694273.
  12. Hirano T, Higuchi T, Ueda M, Inoue T, Kataoka N, Maeda M, Fujiwara H, Fujii S (February 1999). "CD9 is expressed in extravillous trophoblasts in association with integrin alpha3 and integrin alpha5". Mol. Hum. Reprod. 5 (2): 162–7. doi:10.1093/molehr/5.2.162. PMID 10065872.
  13. Horváth G, Serru V, Clay D, Billard M, Boucheix C, Rubinstein E (November 1998). "CD19 is linked to the integrin-associated tetraspans CD9, CD81, and CD82". J. Biol. Chem. 273 (46): 30537–43. doi:10.1074/jbc.273.46.30537. PMID 9804823.
  14. Charrin S, Le Naour F, Oualid M, Billard M, Faure G, Hanash SM, Boucheix C, Rubinstein E (April 2001). "The major CD9 and CD81 molecular partner. Identification and characterization of the complexes". J. Biol. Chem. 276 (17): 14329–37. doi:10.1074/jbc.M011297200. PMID 11278880.
  15. Stipp CS, Orlicky D, Hemler ME (February 2001). "FPRP, a major, highly stoichiometric, highly specific CD81- and CD9-associated protein". J. Biol. Chem. 276 (7): 4853–62. doi:10.1074/jbc.M009859200. PMID 11087758.
  16. Tachibana I, Bodorova J, Berditchevski F, Zutter MM, Hemler ME (November 1997). "NAG-2, a novel transmembrane-4 superfamily (TM4SF) protein that complexes with integrins and other TM4SF proteins". J. Biol. Chem. 272 (46): 29181–9. doi:10.1074/jbc.272.46.29181. PMID 9360996.

External links

Further reading

  • Horejsí V, Vlcek C (1991). "Novel structurally distinct family of leucocyte surface glycoproteins including CD9, CD37, CD53 and CD63". FEBS Lett. 288 (1–2): 1–4. doi:10.1016/0014-5793(91)80988-F. PMID 1879540.
  • Berditchevski F (2002). "Complexes of tetraspanins with integrins: more than meets the eye". J. Cell Sci. 114 (Pt 23): 4143–51. PMID 11739647.
  • Ninomiya H, Sims PJ (1992). "The human complement regulatory protein CD59 binds to the alpha-chain of C8 and to the "b"domain of C9". J. Biol. Chem. 267 (19): 13675–80. PMID 1377690.
  • Miyake M, Koyama M, Seno M, Ikeyama S (1992). "Identification of the motility-related protein (MRP-1), recognized by monoclonal antibody M31-15, which inhibits cell motility". J. Exp. Med. 174 (6): 1347–1354. doi:10.1084/jem.174.6.1347. PMC 2119050. PMID 1720807.
  • Boucheix C, Benoit P, Frachet P, Billard M, Worthington RE, Gagnon J, Uzan G (1991). "Molecular cloning of the CD9 antigen. A new family of cell surface proteins". J. Biol. Chem. 266 (1): 117–22. PMID 1840589.
  • Iwamoto R, Senoh H, Okada Y, Uchida T, Mekada E (1991). "An antibody that inhibits the binding of diphtheria toxin to cells revealed the association of a 27-kDa membrane protein with the diphtheria toxin receptor". J. Biol. Chem. 266 (30): 20463–9. PMID 1939101.
  • Benoit P, Gross MS, Frachet P, Frézal J, Uzan G, Boucheix C, Nguyen VC (1991). "Assignment of the human CD9 gene to chromosome 12 (region P13) by use of human specific DNA probes". Hum. Genet. 86 (3): 268–72. doi:10.1007/bf00202407. PMID 1997380.
  • Lanza F, Wolf D, Fox CF, Kieffer N, Seyer JM, Fried VA, Coughlin SR, Phillips DR, Jennings LK (1991). "cDNA cloning and expression of platelet p24/CD9. Evidence for a new family of multiple membrane-spanning proteins". J. Biol. Chem. 266 (16): 10638–45. PMID 2037603.
  • Higashihara M, Takahata K, Yatomi Y, Nakahara K, Kurokawa K (1990). "Purification and partial characterization of CD9 antigen of human platelets". FEBS Lett. 264 (2): 270–274. doi:10.1016/0014-5793(90)80265-K. PMID 2358073.
  • Masellis-Smith A, Shaw AR (1994). "CD9-regulated adhesion. Anti-CD9 monoclonal antibody induce pre-B cell adhesion to bone marrow fibroblasts through de novo recognition of fibronectin". J. Immunol. 152 (6): 2768–77. PMID 7511626.
  • Chalupny NJ, Kanner SB, Schieven GL, Wee SF, Gilliland LK, Aruffo A, Ledbetter JA (1993). "Tyrosine phosphorylation of CD19 in pre-B and mature B cells". EMBO J. 12 (7): 2691–6. PMC 413517. PMID 7687539.
  • Ikeyama S, Koyama M, Yamaoko M, Sasada R, Miyake M (1993). "Suppression of cell motility and metastasis by transfection with human motility-related protein (MRP-1/CD9) DNA". J. Exp. Med. 177 (5): 1231–1237. doi:10.1084/jem.177.5.1231. PMC 2191011. PMID 8478605.
  • Rubinstein E, Benoit P, Billard M, Plaisance S, Prenant M, Uzan G, Boucheix C (1993). "Organization of the human CD9 gene". Genomics. 16 (1): 132–138. doi:10.1006/geno.1993.1150. PMID 8486348.
  • Radford KJ, Thorne RF, Hersey P (1996). "CD63 associates with transmembrane 4 superfamily members, CD9 and CD81, and with beta 1 integrins in human melanoma". Biochem. Biophys. Res. Commun. 222 (1): 13–18. doi:10.1006/bbrc.1996.0690. PMID 8630057.
  • Schmidt C, Künemund V, Wintergerst ES, Schmitz B, Schachner M (1996). "CD9 of mouse brain is implicated in neurite outgrowth and cell migration in vitro and is associated with the alpha 6/beta 1 integrin and the neural adhesion molecule L1". J. Neurosci. Res. 43 (1): 12–31. doi:10.1002/jnr.490430103. PMID 8838570.
  • Sincock PM, Mayrhofer G, Ashman LK (1997). "Localization of the transmembrane 4 superfamily (TM4SF) member PETA-3 (CD151) in normal human tissues: comparison with CD9, CD63, and alpha5beta1 integrin". J. Histochem. Cytochem. 45 (4): 515–25. doi:10.1177/002215549704500404. PMID 9111230.
  • Rubinstein E, Poindessous-Jazat V, Le Naour F, Billard M, Boucheix C (1997). "CD9, but not other tetraspans, associates with the beta1 integrin precursor". Eur. J. Immunol. 27 (8): 1919–1927. doi:10.1002/eji.1830270815. PMID 9295027.
  • Tachibana I, Bodorova J, Berditchevski F, Zutter MM, Hemler ME (1997). "NAG-2, a novel transmembrane-4 superfamily (TM4SF) protein that complexes with integrins and other TM4SF proteins". J. Biol. Chem. 272 (46): 29181–29189. doi:10.1074/jbc.272.46.29181. PMID 9360996.