Function and interactions of integrins

Integrins are heterodimeric cell adhesion molecules that link the extracell ular matrix to the cytoskeleton. The integrin family in man comprises 24 me mbers, which are the result of different combinations of 1 of 18 alpha- and 1 of 8 beta -subunits. Alternative splicing of mRNA of some alpha- and bet a -subunits and postranslational modifications of integrin subunits further increase the diversity of the integrin family. In their capacity as adhesi on receptors that organize the cytoskeleton, integrins play an important ro le in controlling various steps in the signaling pathways that regulate pro cesses as diverse as proliferation, differentiation, apoptosis, and cell mi gration. The intracellular signals that lead to these effects may be transd uced via cytoplasmic components, which have been identified as integrin-bin ding proteins in yeast two-hybrid screens and which could mediate the coupl ing of integrins to intracellular signaling pathways. In this review an ove rview is given of the function and ligand-binding properties of integrins a s well as of proteins that associate with integrins and may play a role in their signaling function.