The integrin β subunit

The integrin family of cell adhesion receptors plays a fundamental role in the processes involved in cell division, differentiation and movement. The extracellular domains of integrin α/ β heterodimers mediate cell–matrix and cell–cell contacts while their cytoplasmic tails associate with the cytoskeleton. Integrins are capable of transducing information in a bidirectional manner and the β subunit is now recognised to play an important role in this process. Recent studies have led to the identification of a ligand-binding region on the β subunit similar to that already characterised on some α subunits, and sequences in the cytoplasmic tails of the β subunits that interact with cytoskeletal and signalling components. Adhesive events can also play a role in the progression of all four major classes of human disease — neoplastic, inflammatory, traumatic and infectious — and the specific nature of integrin adhesion mechanisms make them an attractive target for therapy.