Integrin alpha(v)beta(3)

The alpha-v beta-3 is a member of the integrin superfamily of adhesion proteins. This class of receptors was named in 1986 to emphasize their role in integrating the intracellular cytoskeleton with the external milieu. Integrins are heterodimeric membrane glycoproteins. Multiple combinations of the 16α and 8 β subunits occur. These form 21 dimers which define the ligand binding specificity and function of the distinct receptors. The α chain is 120-180 kD in size and contains seven 60 amino acid long tandem repeats. The C-terminal 4 bind divalent cations via an E-F hand-like structure.

The vitronectin receptor alpha-v beta-3 is a ubiquitous receptor. It interacts with several ligands. These ligands include vitronectin, fibronectin, osteopontin, and metalloproteinase MMP-2. As a consequence, this integrin plays a role in diverse biological processes such as cell migration, tumor invasion, bone resorption, angiogenesis, and immune responsiveness. During the process of inflammation, circulating human monocytes are able to leave the blood by attaching to, and migrating through, endothelial and sub-endothelial matrices to the site of injury. The alpha-v beta-3 expressed on endothelial cells is involved in the trans-endothelial migration process together with CD31 and CD47.