CHANGES IN CELL SPREADING AND CYTOSKELETAL ORGANIZATION ARE INDUCED BY ADHESION TO A FIBRONECTIN-FIBRIN MATRIX

Plasma fibronectin (pFN) cross-linked to fibrin during the injury resp onse provides a provisional matrix required for cells to begin tissue repair, Using a synthetic matrix of pFN and fibrin as a substrate for cell adhesion and spreading, we have determined that pFN covalently cr oss-linked to fibrin into a complex multimer is functionally distinct from pFN immobilized onto a plastic surface, NIH-3T3 cells on a FN-fib rin matrix reach 50% of the maximal cell area of cells spread on FN-co ated plastic. They neither attach nor spread on cross-linked fibrin al one, Cells on pFN-fibrin matrices form few prominent stress fibers and exhibit clear differences in membrane ruffling and filopodial extensi on when stained with rhodamine-labeled phalloidin. interestingly, thes e differences are enhanced by upregulation of protein kinase C. These data suggest that cell-FN interactions can be modified by the molecula r context of the protein within the extracellular matrix resulting in distinct cell morphology and cytoskeletal organization. (C) 1996 by Th e American Society of Hematology.