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Investigating von Willebrand Factor Pathophysiology Using a Flow Chamber Model of von Willebrand Factor-platelet String Formation
Published on: August 14, 2017
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Autoregulation of von Willebrand factor function by a disulfide bond switch
Diego Butera1, Freda Passam2, Lining Ju3
1The Centenary Institute, Newtown, New South Wales, Australia.
Science Advances
|March 7, 2018
Summary
A disulfide bond switch regulates von Willebrand factor (VWF) binding to platelet receptors. This mechanism, controlled by the A2 domain
Area of Science:
- Biochemistry
- Biophysics
- Molecular Biology
Background:
- Platelet glycoprotein Ib (GPIb) binding to von Willebrand factor (VWF) is crucial for hemostasis and thrombosis.
- VWF activation involves force-induced exposure of the GPIb binding site, but its biochemical basis is unclear.
Purpose of the Study:
- To elucidate the biochemical mechanism of VWF mechanopresentation.
- To investigate the role of the A2 domain in VWF autoinhibition.
Main Methods:
- Protein chemical studies
- Biophysical analyses
- Functional assays
- Molecular dynamics simulations
Main Results:
- Autoinhibition of VWF's GPIb binding site is controlled by a disulfide bond in the A2 domain.
- Cleavage of this disulfide bond allows the A2 domain to inhibit GPIb binding.
- Disulfide bond cleavage is less frequent in VWF from heart failure patients on ECMO support.
Conclusions:
- A disulfide bond acts as a redox switch regulating VWF mechanopresentation.
- Altered VWF disulfide bond status may impact platelet aggregation in certain patient populations.
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