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Symbol CD9 contributors: mct/shn - updated : 04-09-2017
HGNC name CD9 molecule
HGNC id 1709
Location 12p13.31      Physical location : 6.309.554 - 6.347.427
Synonym name
  • 5H9 antigen
  • BA-2/p24 antigen
  • CD9 antigen
  • CD9 antigen (p24)
  • cell growth-inhibiting gene 2 protein
  • leukocyte antigen MIC3
  • motility related protein-1
  • tetraspanin-29
  • Synonym symbol(s) MIC3, BA2, P24, MRP1, DRAP27, 5H9, BTCC-1, GIG2, MRP-1, TSPAN29, TSPAN-29, BTCC-1
    TYPE functioning gene
    STRUCTURE 37.96 kb     8 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    MAPPING cloned Y linked Y status confirmed
    Map pter - D12S356 - D12S374 - CD9 - D12S1623 -D12S1625 - cen
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    8 - 1246 25.4 228 - 2007 17582603
    Type ubiquitous
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Cardiovascularheart   highly
    Reproductivemale systemtestis  highly
    Urinarykidney   highly
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    Blood / Hematopoieticbone marrow   
    SystemCellPubmedSpeciesStageRna symbol
    Blood/Hematopoieticmature hematopoietic
    Lymphoid/ImmuneB cell
    Lymphoid/ImmuneT cell
    cell lineage
    cell lines
    at STAGE
    conjugated GlycoP
    interspecies ortholog to Cd9, Mus musculus
    ortholog to Cd9, Rattus norvegicus
    ortholog to CD9, Pan troglodytes
  • transmembrane 4 superfamily
  • tetraspanin (TM4SF) family
  • CATEGORY antigen
    SUBCELLULAR LOCALIZATION     plasma membrane
  • expressed in a specific membrane microdomain, called "lipid raft"
  • located intracellularly as well as in the plasma membrane at cell-cell contact sites and in long spike-like extensions, whereas cells in confluent cultures predominantly showed plasma membrane staining
  • basic FUNCTION
  • involved in platelet activation and agregation
  • integral membrane proteins that facilitate the organization of membrane and intracellular signaling molecules into dynamic signaling microdomains, tetraspanin-enriched microdomains (TEMs)
  • implicated in cell adhesion, motility and proliferation
  • playing a crucial role for cell fusion during osteoclastogenesis after activation of the RANK/RANKL system, through its expression in lipid rafts
  • inhibiting the proliferation and tumorigenicity of colon carcinoma cells
  • regulates the actin cytoskeleton by downregulating of the WASF2, through the WNT-independent signal pathway
  • essential for sperm-egg fusion , and
  • having a function in migration and adhesion of these cells
  • involved in the migration of retinal microvascular endothelial cells
  • its mobility and partitioning are both dependent on its palmitoylation and plasma membrane cholesterol
  • has a role in the maturation of transmembrane TGFA and its stabilization at the cell surface, and in the cell-surface distribution in polarized epithelial cells
  • role in the presentation of TGFA in epithelial and carcinoma cells, whose physiology is driven by ligand-induced EGFR activation
  • might have an important role that attenuates EGFR signaling (not only associates EGFR but also a new regulator, which may affect EGF-induced signaling in cancer cells)
  • plays roles in cell proliferation and attachment as well as engraftment and can be considered as a useful marker to predict the efficacy of adipose-derived mesenchymal stem cells
  • with CD63 ssociate with a type II phosphatidylinositol 4-kinase, PI4K55, in both resting and activated platelets
  • with CD63 and CD81 are all involved in multinucleated giant cells formation, but play distinct roles
  • plays stimulus-independent roles in angiogenesis
  • appears to, at least in part, contribute to the delocalization of integrins and MMP14, disruption of which may prevent angiogenesis
  • involved in the proliferation but not survival of relatively quiescent endothelial cells
  • CD9 expression on human germinal center (GC) -B cells may reflect the status of GC-B cell activation or differentiation
  • CD9 is a marker for plasma cells precursors (
  • normal muscle regeneration requires tight control of muscle cell fusion by tetraspanins CD9 and CD81
  • requirement of two spermatozoon factors, IZUMO1 and SPACA6, and two oocyte factors, CD9 and the IZUMO1R, has been proven in Sperm-egg fusion
  • IZUMO1 and C16orf92 on the sperm membrane and CD9 and IZUMO1R/FOLR4 on the oocyte membrane have been identified as fusion-required proteins
  • role of IZUMO1R and CD9 in PTK2B activation and actin remodeling at the sperm binding site
    a component
  • constituent of membrane glycoprotein
  • association with CD21 (CR2)
    small molecule
  • CD59
  • Heparin-binding EGF-like growth factor
  • CD63
  • NAG-2
  • CD19
  • alpha2, alpha3 and alpha5-integrins
  • colligin/Hsp47
  • FPRP
  • protein kinase C
  • EWI-2
  • c-kit receptor tyrosine kinase
  • CD36
  • CD81 and CD53
  • CD38/HLA-DR complex
  • ZDHHC2
  • TGFalpha
  • presumptive target for CELF1-mediated regulation
  • ALCAM directly associates with the tetraspanin CD9 on the leukocyte surface in protein complexes that also include the metalloproteinase ADAM17/TACE
  • cell & other
    Other regulated by CELF1 (directly controls CD9 expression)
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral     --low  
    in endometrioid adenocarcinoma and in squamous cell carcinoma of the head and neck with high grade and poor prognosis
    tumoral     --low  
    associated with the negative progression and metastasis outbreak of multiple cancer type, including prostate, breast, colon, non-small cell lung cancer, oral squamous cell carcinoma
    Variant & Polymorphism
    Candidate gene
    Therapy target
    inhibition of CD9 expression or function via intravitreous injections of siRNA-CD9 or anti-CD9 antibodies may provide a new therapeutic strategy for angiogenesis such as that observed in certain ocular diseases
  • CD9-/- mouse females displayed a severe reduction of fertility
  • litter size from CD9-/- mouse was less than 2% of that of the wild type
  • CD9 homozygous mutant mouse females were infertile