Integrins are a family of transmembrane proteins. A total 17 integrin alpha chains and 8 beta chains have been identified. The association of integrin alpha and beta chains forms 25 integrin complexes which serve as extracellular matrix receptors and play important roles in cell adhesion and development. Integrin beta5 is a 95 kD glycoprotein heterodimer with the alphaV subunit and is found on many types of tissue cells, such as epithelial cells, endothelial cells, keratinocytes, and osteoblastic cells. The alphaV/beta5 integrin complex binds to vitronectin.