Roles of integrins in fibronectin matrix assembly.

Fibronectin (Fn) matrix assembly is a dynamic cellular process in which the soluble dimeric Fn molecules are assembled into insoluble, disulfide bond stabilized fibrillar polymeric matrix. Fn matrix assembly requires specific Fn binding integrins. Several Fn binding integrins that are capable of mediating Fn matrix assembly have been identified. They include alpha5beta1, alphaIIb(beta3) and alpha(v)beta3 integrins. Cells regulate the matrix assembly process not only by controlling cell surface expression level of the Fn binding integrins but also by modulating Fn binding and cytoskeleton binding activities of the integrins. A major challenge of future studies is to delineate the signal transduction pathway that regulates Fn matrix assembly.