ADAMTS13 bound to endothelial cells exhibits enhanced cleavage of von Willebrand factor.
ADAMTS13 is a plasma metalloprotease that cleaves ultralarge von Willebrand factor multimers to generate less thrombogenic fragments. Although this cleavage can occur at the surface of endothelial cells, it is currently unknown whether this process involves binding of the ADAMTS13 to the endothelial cell plasma membrane. Using different assay systems, we present evidence that ADAMTS13 binds to endothelial cells in a specific, reversible, and time-dependent manner with a K(d) of 58 nm. This binding requires the COOH-terminal thrombospondin type 1 repeats of the protease. Binding is inhibited in the presence of heparin and by trypsin treatment of the cells. ADAMTS13 that was prebound to endothelial cells exhibited increased proteolysis of VWF as compared with ADAMTS13 present only in solution. These data support the notion that cleavage of VWF occurs mainly at the endothelial cell surface.
Vomund
Anthony N
AN
Division of Hematology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Majerus
Elaine M
EM
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000071120:ADAMTS13 Protein; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D014841:von Willebrand Factor / Q000378:metabolism*
D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human