title: The p.R1819_C1948delinsS mutation makes von Willebrand factor ADAMTS13-resistant and reduces its collagen-binding capacity.
abstract: This report concerns abnormal ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) and collagen interactions coinciding with the p.R1819_C1948delinsS von Willebrand factor (VWF) mutation associated with the deletion of the C-terminus of the A3 domain (amino acids 1819-1947) in a patient with a history of bleeding. The von Willebrand disease (VWD) phenotype of the patient featured low plasma and platelet VWF, multimers with smears extending over the highest normal oligomers in plasma, but not platelets, and an impaired collagen-binding capacity. In vitro full-length p.R1819_C1948delinsS VWF expression showed impaired VWF release, increased cellular content with normally-multimerized VWF and impaired collagen binding. The recombinant p.R1819_C1948delinsS VWF fragment, extending from domains A2 to B3 (p.R1819_C1948delinsS A2-B3 VWF), was completely resistant to proteolysis by ADAMTS13 in the presence of 1·5 mol/l urea, unlike its normal counterpart. The defect stems from impaired ADAMTS13 binding to p.R1819_C1948delinsS A2-B3, analysed under static conditions. Partial deletion of the C-terminus of the A3 domain thus makes VWF resistant to ADAMTS13, interfering with ADAMTS13 binding to VWF, and impairing the collagen-binding capacity of VWF. The p.R1819_C1948delinsS mutation has both haemorrhagic features (defective collagen binding, reduced VWF levels) and prothrombotic (ADAMTS13 resistance) features, and the latter probably mitigate the patient's bleeding symptoms.
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Daidone
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Saga
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barbon
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Pontara
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Cattini
authors.affiliation: Pharmaceutical Chemistry and Pharmacology Department, University of Padua, Padua, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Morpurgo
authors.affiliation: Department of Biomedical Sciences, University of Padua, Padua, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanotti
authors.affiliation: Thrombohaemorrhagic Disorders Unit, Department of Medicine, University of Padua, Padua, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casonato
mesh_terms: D051722:ADAM Proteins / Q000235:genetics* / Q000378:metabolism; D000071120:ADAMTS13 Protein; D003094:Collagen / Q000378:metabolism; D005260:Female; D006470:Hemorrhage / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D054643:INDEL Mutation; D008297:Male; D011485:Protein Binding; D014841:von Willebrand Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: D014841:von Willebrand Factor; D003094:Collagen; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human
keywords: ADAMTS13; VWF gene mutation; VWF resistance to ADAMTS13 proteolysis; VWF-ADAMTS13 binding; von Willebrand disease