Integrins are transmembrane proteins that function in cellular adhesion to extracellular matrix (ECM) components such as collagens, fibronectin and laminin or endothelial expressed proteins.
Table 1 lists key integrins and their ligands. Each integrin is a heterodimer of one of several alpha subunits and one of several beta subunits that combine to confer specificity to the extracellular binding domain. Binding of the ligand results in modification of the interaction of the cytoplasmic tails of the molecule, both directly and indirectly, with several intracellular proteins, including protein kinases and cytoskeletal proteins. The resulting signal cascade may influence pathways as diverse as the cell cycle to cell migration.