Integrin alpha-9 is a protein that in humans is encoded by the ITGA9 gene. Cytogenetic location: 3p22.2 Function 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 tenascin-C, VCAM1 and osteopontin. Expression of this gene has been found to be upregulated in small cell lung cancers. Interactions 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. α9β1 binding is independent of the RGD peptide sequence. References Further reading External links ITGA9 Info with links in the Cell Migration Gateway Integrins