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The type 2B p.R1306W natural mutation of von Willebrand factor dramatically enhances the multimer sensitivity to shear stress
- Source :
- Journal of thrombosis and haemostasis : JTH. 11(9)
- Publication Year :
- 2013
-
Abstract
- Shear stress triggers conformational stretching of von Willebrand factor (VWF), which is responsible for its self-association and binding to the platelet receptor glycoprotein (GP)Ibα. This phenomenon supports primary hemostasis under flow. Type 2B VWF natural mutants are considered to have increased affinity for platelet GPIbα.To assess the mechanism responsible for the enhanced interaction of the p.R1306W VWF mutant with the platelet receptor.The interaction of GPIbα with wild-type (WT) and p.R1306W VWF multimers and A1-A2-A3 constructs was investigated with surface plasmon resonance spectroscopy. Analysis of the static VWF conformation in solution was performed with dynamic light scattering spectroscopy. The shear stress-induced self-association of VWF multimers was investigated with atomic force microscopy (AFM) over a 0-60 dyn cm(-2) range.WT VWF did not interact with GPIbα under static conditions, whereas the mutant at ~ 2 μg mL(-1) already bound to the receptor. By contrast, the WT and p.R1306W-A1-A2-A3 constructs showed comparable affinities for GPIbα (Kd ~ 20 nm). The hydrodynamic diameter of resting R1306W VWF multimers was significantly greater than that of the wild type (210 ± 60 nm vs. 87 ± 22 nm). At shear forces of 14 dyn cm(-2) , the p.R1306W multimers rapidly changed conformation, entering a regime of self-aggregation, which, in contrast, was induced for WT VWF by shear forces of 30 dyn cm(-2) . Mechanical stretching AFM experiments showed that p.R1306W multimers needed less energy per length unit (~ 10 pN) to be stretched than the WT protein.The increased affinity of p.R1306W VWF for GPIbα arises mostly from higher sensitivity to shear stress, which facilitates exposure of GPIbα binding sites.
- Subjects :
- Microscopy, Atomic Force
Biopolymers
Von Willebrand factor
Platelet adhesiveness
von Willebrand Factor
Von Willebrand disease
medicine
Shear stress
Humans
Platelet
Binding site
Surface plasmon resonance
Settore BIO/10 - BIOCHIMICA
biology
Chemistry
Wild type
Hematology
Surface Plasmon Resonance
medicine.disease
Atomic Force Microscopy
Immunology
Mutation
biology.protein
Biophysics
Stress, Mechanical
Von Willebrand Disease
circulatory and respiratory physiology
Subjects
Details
- ISSN :
- 15387836
- Volume :
- 11
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- Journal of thrombosis and haemostasis : JTH
- Accession number :
- edsair.doi.dedup.....e1ae4a28be0b636a2f069e5a607fe2d0