Comparative analysis of type 2b von Willebrand disease mutations: implications for the mechanism of von Willebrand factor binding to platelets.

Published

Journal Article

von Willebrand factor (vWF) is a multimeric glycoprotein that forms an adhesive link following vascular injury between the vessel wall and its primary ligand on the platelet surface, glycoprotein Ib (GpIb). Type 2b von Willebrand disease (vWD) is a qualitative form of vWD resulting from enhanced binding of vWF to platelets. Molecular characterization of the vWF gene in patients with type 2b vWD has resulted in identification of a panel of mutations associated with this disorder, all clustered within the GpIb binding domain in exon 28 of the vWF gene. We have expressed six of the most common type 2b vWD mutations in recombinant vWF and show that each mutation produces a similar increase in vWF binding to platelets in the absence or presence of ristocetin. Furthermore, expression of more than one type 2b vWD mutation in the same molecule (cis) or in different molecules within the same multimer (trans) failed to produce an increase in vWF platelet binding compared with any of the individually expressed mutations. Taken together, these data support the hypothesis that the vWF GpIb binding domain can adopt either a discrete "on" or "off" conformation, with most type 2b vWD mutations resulting in vWF locked in the on conformation. This model may have relevance to other adhesive proteins containing type A domains.

Full Text

Duke Authors

Cited Authors

  • Cooney, KA; Ginsburg, D

Published Date

  • March 15, 1996

Published In

Volume / Issue

  • 87 / 6

Start / End Page

  • 2322 - 2328

PubMed ID

  • 8630394

Pubmed Central ID

  • 8630394

International Standard Serial Number (ISSN)

  • 0006-4971

Language

  • eng

Conference Location

  • United States