Interaction of fibrin(ogen) with fibronectin: further characterization and localization of the fibronectin-binding site.

The interaction of fibronectin with fibrin and its incorporation into fibrin clots are thought to be important for the formation of a provisional matrix that promotes cell adhesion and migration during wound healing. However, it is still unclear whether fibronectin interacts with both fibrin and fibrinogen or fibrin only and whether fibronectin binds exclusively to the fibrin(ogen) αC domains. To address these questions, we studied the interaction of fibronectin with fibrinogen, fibrin, and their proteolytic and recombinant fragments. In both ELISA and surface plasmon resonance (SPR) experiments, immobilized fibrinogen did not bind fibronectin at all, but after conversion to fibrin, it bound fibronectin with high affinity. To test which regions of fibrin are involved in this binding, we studied the interaction of fibronectin with the fibrin-derived D−D:E1 complex and a recombinant αC fragment (residues Aα221−610) corresponding to the αC domain that together encompass the whole fibrin(ogen) molecule. In EL...