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Platelet vinculin: a substrate of activated factor XIII
G M Asijee1, L Muszbek, J Kappelmayer
1Department of Clinical Chemistry, University School of Medicine, Debrecen, Hungary.
Biochimica Et Biophysica Acta
|June 13, 1988
Summary
Factor XIII (FXIII), an enzyme in blood coagulation, may stabilize cellular cytoskeletons. Research shows FXIIIa links small amines to vinculin, a cytoskeleton protein, suggesting a role in cellular structure.
Area of Science:
- Biochemistry
- Cell Biology
- Hematology
Background:
- Factor XIII (FXIII) is found in plasma and intracellularly in platelets, monocytes, and macrophages.
- The intracellular function of FXIII remains largely uncharacterized.
- Activated FXIII (FXIIIa) is a transglutaminase with limited known protein substrates.
Purpose of the Study:
- To investigate the intracellular function of Factor XIII (FXIII).
- To identify potential intracellular substrates for activated Factor XIII (FXIIIa).
- To explore the role of FXIIIa in cellular processes involving vinculin.
Main Methods:
- Utilized dansylcadaverine, radiolabeled histamine, and putrescine as amine donors.
- Investigated the interaction of FXIIIa with vinculin.
- Quantitatively determined the incorporation of amines into vinculin.
- Examined the crosslinking potential of FXIIIa with vinculin and fibrinogen.
Main Results:
- FXIIIa successfully linked dansylcadaverine, radiolabeled histamine, and putrescine to vinculin.
- A single glutamine residue in vinculin acts as the acyl donor for amine incorporation.
- Vinculin cannot crosslink to itself but can covalently bind to fibrinogen.
- These findings suggest FXIIIa's role in epsilon-(gamma-glutamyl)lysyl crosslink formation.
Conclusions:
- Factor XIIIa (FXIIIa) can modify vinculin by incorporating small amines.
- The ability of FXIIIa to crosslink vinculin to fibrinogen suggests a role in extracellular matrix interactions.
- Given FXIIIa's known action on platelet actin and myosin, and vinculin's association with the cytoskeleton, FXIII likely stabilizes the cytoskeleton during specific cellular functions.