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Integrin, alpha 9
External IDs OMIM603963 MGI104756 HomoloGene1664 ChEMBL: 3170 GeneCards: ITGA9 Gene
RNA expression pattern
PBB GE ITGA9 gnf1h04097 s at tn.png
More reference expression data
Species Human Mouse
Entrez 3680 104099
Ensembl ENSG00000144668 ENSMUSG00000039115
UniProt Q13797 B8JK39
RefSeq (mRNA) NM_002207 NM_001113514
RefSeq (protein) NP_002198 NP_001106986
Location (UCSC) Chr 3:
37.45 – 37.82 Mb
Chr 9:
118.61 – 118.9 Mb
PubMed search [1] [2]

Integrin alpha-9 is a protein that in humans is encoded by the ITGA9 gene.[1][2][3]


This gene encodes an alpha integrin. Integrins are heterodimeric integral membrane glycoproteins composed of an alpha chain and a beta chain that mediate cell-cell and cell-matrix adhesion. The protein encoded by this gene, when bound to the beta 1 chain, forms an integrin that is a receptor for VCAM1, cytotactin and osteopontin. Expression of this gene has been found to be upregulated in small cell lung cancers.[3]


The α9 subunit forms a heterodimeric complex with a β1 subunit to form the α9β1 integrin. This integrin participates in cell adhesion with various ligands in the extracellular matrix (ECM), including extra domain A (EDA) fibronectin, tenascin-C, ADAMs, EMELIN1, osteopontin, and VEGF.[4] α9β1 binding is independent of the RGD peptide sequence.


  1. ^ Palmer EL, Rüegg C, Ferrando R, Pytela R, Sheppard D (Jan 1994). "Sequence and tissue distribution of the integrin alpha 9 subunit, a novel partner of beta 1 that is widely distributed in epithelia and muscle". J Cell Biol 123 (5): 1289–97. doi:10.1083/jcb.123.5.1289. PMC 2119880. PMID 8245132. 
  2. ^ Hibi K, Yamakawa K, Ueda R, Horio Y, Murata Y, Tamari M, Uchida K, Takahashi T, Nakamura Y, Takahashi T (Feb 1994). "Aberrant upregulation of a novel integrin alpha subunit gene at 3p21.3 in small cell lung cancer". Oncogene 9 (2): 611–9. PMID 8290272. 
  3. ^ a b "Entrez Gene: ITGA9 integrin, alpha 9". 
  4. ^ Høye AM, Couchman JR, Wewer UM, Fukami K, Yoneda A (May 2012). "The newcomer in the integrin family: integrin α9 in biology and cancer.". Advances in biological regulation 52 (2): 326–39. doi:10.1016/j.jbior.2012.03.004. PMID 22781746. 

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