Title :
Plasmin Cleaves Von Willebrand Factor at K1491-R1492 in the A1-A2 Linker Region in a Shear- and Glycan-Dependent Manner In Vitro
Abstract :
- Previous studies have demonstrated a role for plasmin in regulating plasma von Willebrand factor ( VWF ) multimer com position
- Moreover, emerging data have shown that plasmin-induced cleavage of VWF is of particular importance in specific pathological states
- Interestingly, plasmin has been successfully used as an alternative to ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif ) in a mouse model of thrombotic thrombocytopenic purpura
- Consequently, elucidating the molecular mechanisms through which plasmin binds and cleaves VWF is not only of basic scientific interest but also of direct clinical importance
- Our aim was to investigate factors that modulate the susceptibility of human VWF to proteolysis by plasmin
- We have adapted the VWF vortex proteolysis assay to allow for time-dependent shear exposure studies
- We show that globular VWF is resistant to plasmin cleavage under static conditions, but is readily cleaved by plasmin under shear
- Although both plasmin and ADAMTS13 cleave VWF in a shear-dependent manner, plasmin does not cleave at the Tyr1605-Met1606 ADAMTS13 proteolytic site in the A2 domain
- Rather under shear stress conditions, or in the presence of denaturants, such as urea or ristocetin, plasmin cleaves the K1491-R1492 peptide bond within the VWF A1-A2 linker region
- Finally, we demonstrate that VWF susceptibility to plasmin proteolysis at K1491-R1492 is modulated by local N-linked glycan expression within A1A2A3, and specifically inhibited by heparin binding to the A1 domain
- Improved understanding of the plasmin- VWF interaction offers exciting opportunities to develop novel adjunctive therapies for the treatment of refractory thrombotic thrombocytopenic purpura
Output (sent_index, trigger,
protein,
sugar,
site):
Output(Part-Of) (sent_index,
protein,
site):
- 0. Plasmin Cleaves Von Willebrand Factor, -
- 0. Plasmin Cleaves Von Willebrand Factor, K1491-R1492
- 1. von Willebrand factor, position
- 10. A1, domain
- 3. disintegrin, motif
- 3. metalloproteinase, motif
- 3. thrombospondin type 1, motif
- 8. Tyr1605-Met1606 ADAMTS13, site
- 9. VWF, region
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):