Semin Thromb Hemost 2005; 31(6): 659-672
DOI: 10.1055/s-2005-925472
Copyright © 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.

Molecular Biology of ADAMTS13 and Diagnostic Utility of ADAMTS13 Proteolytic Activity and Inhibitor Assays

Suresh G. Shelat1 , 3 , Jihui Ai1 , X. Long Zheng1 , 2 , 3
  • 1Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia
  • 2Assistant Professor, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia
  • 3The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
Further Information

Publication History

Publication Date:
30 December 2005 (online)

ABSTRACT

ADAMTS13, a reprolysin-like metalloprotease, limits platelet-rich thrombus formation in the small arteries by cleaving von Willebrand factor (vWF) at the Tyr1605-Met1606 peptide bond. Deficiency of plasma ADAMTS13 activity, due to either an inherited or an acquired etiology, may lead to a potentially lethal syndrome, thrombotic thrombocytopenic purpura (TTP). Molecular cloning and characterization of the ADAMTS13 gene have provided further insight into the structure-function relationships, biosynthesis, and regulation of the ADAMTS13 protease, in addition to understanding the pathogenesis of TTP and perhaps other thrombotic disorders. ADAMTS13 consists of a short propeptide, a typical reprolysin-like metalloprotease domain, followed by a disintegrin-like domain, first thrombospondin type 1 (TSP1) repeat, Cys-rich domain, and spacer domain. The carboxyl terminus of ADAMTS13 has seven more TSP1 repeats and two CUB domains. ADAMTS13 is synthesized mainly in hepatic stellate cells, but also in vascular endothelial cells. Recognition and cleavage of vWF require the proximal carboxyl terminal domains, but not the middle and distal carboxyl terminal domains. Cleavage of vWF appears to be modulated by shear force, binding to platelet or platelet glycoprotein-1bα, heparin, inflammatory cytokine (interleukin-6), and chloride ion. At the site of thrombus formation, the ADAMTS13 may be inactivated by thrombin, plasmin, and factor Xa. Having a sensitive and specific assay for ADAMTS13 activity is not only critical to understand the basic biology of ADAMTS13 protease, but also to facilitate a more timely and accurate clinical diagnosis of TTP, and to initiate potentially life-saving plasma exchange therapy. Although many assays have been developed and tested for clinical applications, the fluorescent resonance energy transfer-vWF73 assay appears to be the simplest and most promising assay to date.

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X. Long ZhengM.D. Ph.D. 

Assistant Professor, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania

34th St. and Civic Center Blvd, Abramson Research Center 816G, Philadelphia, PA 19104

Email: zheng@email.chop.edu