ASSEMBLY OF FIBRONECTIN INTO EXTRACELLULAR-MATRIX

Assembly of fibronectin into a fibrillar matrix is part of a complicated process by which the intracellular cytoskeleton determines the pattern of assembly of extracellular matrix and vice versa. Assembly is restricted to dimeric fibronectin molecules with intact amino-terminal modules and occurs at specialized cell-surface assembly sites. Cellular display of assembly sites is labile and requires that cells be under tension and have functional beta1 integrins. Assembly is described as a stepwise event in which protameric dimers bind to assembly sites, multimerization occurs, and assembly sites are regenerated.