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Fibronectin and fibrin gel structure.
The Journal of Biological Chemistry
|February 10, 1985
Summary
Plasma fibronectin is incorporated into fibrin alpha-chains by thrombin-activated Factor XIII (FXIIIaT), but not by batroxobin-activated FXIII (FXIIIaB). This difference highlights distinct substrate specificities affecting fibrin cross-linking and gel structure.
Area of Science:
- Biochemistry
- Hematology
- Protein Chemistry
Background:
- Plasma fibronectin is a glycoprotein involved in various biological processes, including wound healing and cell adhesion.
- Fibrinogen is the precursor to fibrin, the main protein in blood clots, and its polymerization forms a gel matrix.
- Factor XIII (FXIII) is a transglutaminase that cross-links fibrin, stabilizing blood clots.
Purpose of the Study:
- To investigate the differential incorporation of plasma fibronectin into fibrin gels mediated by thrombin-activated FXIII (FXIIIaT) versus batroxobin-activated FXIII (FXIIIaB).
- To elucidate the role of fibronectin incorporation in modulating the structural properties of fibrin gels.
- To understand the substrate specificity differences between FXIIIaT and FXIIIaB concerning fibronectin and fibrin cross-linking.
Main Methods:
- Comparative analysis of fibronectin incorporation into fibrin gels formed using FXIIIaT and FXIIIaB.
- Assessment of fibrin alpha-chain and gamma-chain cross-linking using different FXIII activators.
- Measurement of fibrin gel turbidity and permeability coefficient (Ks) to evaluate structural changes.
- Investigation of fibronectin incorporation into preformed fibrin gels.
Main Results:
- Plasma fibronectin is covalently incorporated into fibrin alpha-chains exclusively by FXIIIaT, not FXIIIaB.
- FXIIIaB catalyzes gamma-gamma cross-linking but fails to induce alpha-chain cross-linking, unlike FXIIIaT.
- Fibronectin incorporation into fibrin gels increases turbidity and decreases permeability, suggesting increased strand width.
- Fibronectin can be incorporated into both forming and preformed fibrin gels, indicating potential distinct binding sites.
Conclusions:
- FXIIIaT and FXIIIaB exhibit distinct substrate specificities, with FXIIIaT mediating fibronectin incorporation and alpha-chain cross-linking.
- Fibronectin incorporation into fibrin gels alters their structural properties, potentially influencing gel network formation and stability.
- The findings suggest that fibronectin incorporation and fibrin cross-linking may involve different interaction sites within the fibrin matrix.