A common mechanism by which type 2A von Willebrand Disease mutations enhance ADAMTS13 proteolysis revealed with a von Willebrand Factor A2 domain FRET construct

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Title: A common mechanism by which type 2A von Willebrand Disease mutations enhance ADAMTS13 proteolysis revealed with a von Willebrand Factor A2 domain FRET construct
Authors: Lane, DA
Lynch, CJ
Millar, C
Rueda, D
Cawte, A
Item Type: Journal Article
Abstract: Rheological forces in the blood trigger the unfolding of von Willebrand factor (VWF) and its A2 domain, exposing the scissile bond for proteolysis by ADAMTS13. Under quiescent conditions, the scissile bond is hidden by the folded structure due to the stabilisation provided by the structural specialisations of the VWF A2 domain, a vicinal disulphide bond, a calcium binding site and a N1574-glycan.The reduced circulating high MW multimers of VWF in patients with type 2A von Willebrand disease (VWD) may be associated with mutations within the VWF A2 domain and this is attributed to enhanced ADAMTS13 proteolysis. We investigated 11 VWF A2 domain variants identified in patients with type 2A VWD. In recombinant full-length VWF, enhanced ADAMTS13 proteolysis was detected for all of the expressed variants in the presence of urea-induced denaturation. A subset of the FLVWF variants displayed enhanced proteolysis in the absence of urea. The mechanism of enhancement was investigated using a novel VWF A2 domain FRET construct. In the absence of induced unfolding, 7/8 of the expressed mutants exhibited a disrupted domain fold, causing spatial separation of the N- and C- termini. Three of the type 2A mutants were not secreted when studied within the VWF A2 domain FRET construct. Urea denaturation revealed for all 8 secreted mutants reduced unfolding cooperativity and stability of the VWF A2 domain. As folding stability was progressively disrupted, proteolysis by ADAMTS13 increased. Due to the range of folding stabilities and wide distribution of VWF A2 domain mutations studied, we conclude that these mutations disrupt regulated folding of the VWF A2 domain. They enhance unfolding by inducing separation of N- and C-termini, thereby promoting a more open conformation that reveals its binding sites for ADAMTS13 and the scissile bond.
Issue Date: 29-Nov-2017
Date of Acceptance: 7-Nov-2017
URI: http://hdl.handle.net/10044/1/53231
DOI: https://dx.doi.org/10.1371/journal.pone.0188405
ISSN: 1932-6203
Publisher: Public Library of Science (PLoS)
Journal / Book Title: PLoS ONE
Volume: 12
Issue: 11
Copyright Statement: © 2017 Lynch et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Sponsor/Funder: British Heart Foundation
Medical Research Council
Funder's Grant Number: FS/14/21/30733
Keywords: MD Multidisciplinary
General Science & Technology
Publication Status: Published
Article Number: e0188405
Appears in Collections:Department of Medicine
Faculty of Medicine

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