title: Local elongation of endothelial cell-anchored von Willebrand factor strings precedes ADAMTS13 protein-mediated proteolysis.
abstract: Platelet-decorated von Willebrand factor (VWF) strings anchored to the endothelial surface are rapidly cleaved by ADAMTS13. Individual VWF string characteristics such as number, location, and auxiliary features of the ADAMTS13 cleavage sites were explored here using imaging and computing software. By following changes in VWF string length, we demonstrated that VWF strings are cleaved multiple times, successively shortening string length in the function of time and generating fragments ranging in size from 5 to over 100 μm. These are larger than generally observed in normal plasma, indicating that further proteolysis takes place in circulation. Interestingly, in 89% of all cleavage events, VWF strings elongate precisely at the cleavage site before ADAMTS13 proteolysis. These local elongations are a general characteristic of VWF strings, independent of the presence of ADAMTS13. Furthermore, large elongations, ranging in size from 1.4 to 40 μm, occur at different sites in space and time. In conclusion, ADAMTS13-mediated proteolysis of VWF strings under flow is preceded by large elongations of the string at the cleavage site. These elongations may lead to the simultaneous exposure of many exosites, thereby facilitating ADAMTS13-mediated cleavage.
authors: Laboratory for Thrombosis Research, Katholieke Universiteit Leuven Campus Kortrijk, B-8500 Kortrijk, Belgium.
authors: Karen
authors: K
authors: De Ceunynck
authors: Susana
authors: S
authors: Rocha
authors: Hendrik B
authors: HB
authors: Feys
authors: Simon F
authors: SF
authors: De Meyer
authors: Hiroshi
authors: H
authors: Uji-i
authors: Hans
authors: H
authors: Deckmyn
authors: Johan
authors: J
authors: Hofkens
authors: Karen
authors: K
authors: Vanhoorelbeke
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000071120:ADAMTS13 Protein; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D006801:Humans; D059748:Proteolysis; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human