Thromb Haemost 1999; 81(01): 96-103
DOI: 10.1055/s-0037-1614425
Review Article
Schattauer GmbH

Monocyte Plasminogen Activator Inhibitor 2 (PAI-2) Inhibits u-PA-mediated Fibrin Clot Lysis and Is Cross-linked to Fibrin

Helen Ritchie
1   From the Departments of Molecular and Cell Biology and, University of Aberdeen, Aberdeen, UK
,
Linda A. Robbie
1   From the Departments of Molecular and Cell Biology and, University of Aberdeen, Aberdeen, UK
2   From the Departments of Medicine and Therapeutics, University of Aberdeen, Aberdeen, UK
,
Seonag Kinghorn
1   From the Departments of Molecular and Cell Biology and, University of Aberdeen, Aberdeen, UK
,
Rachel Exley
1   From the Departments of Molecular and Cell Biology and, University of Aberdeen, Aberdeen, UK
,
Nuala A. Booth
1   From the Departments of Molecular and Cell Biology and, University of Aberdeen, Aberdeen, UK
› Author Affiliations
Further Information

Correspondence to:

Helen Ritchie, PhD
Dept of Molecular and Cell Biology
University of Aberdeen
Institute of Medical Sciences
Aberdeen, Scotland, UK, AB25 2ZD
Phone: +44-1224-681818 ext 54575   
Fax: +44-1224-273144   

Publication History

Received29 June 1998

Accepted after revision22 September 1998

Publication Date:
08 December 2017 (online)

 

Summary

Plasminogen activator inhibitor 2 (PAI-2) is a major product of activated human monocytes. Here we show that monocytes inhibited u-PA- but not t-PA-mediated fibrinolysis, by secreting PAI-2 into an overlying fibrin clot. Extracts of arterial and venous human thrombi were found to contain active PAI-2. PAI-2 was cross-linked to fibrin in a reaction catalyzed by two major transglutaminases (TG), tissue TG and factor XIII. The activity of PAI-2 was not affected by such cross-linking. Cross-linking of PAI-2 to fibrin was inhibited by Tridegin, a specific inhibitor of TG, and also by EDTA and iodoacetamide. The use of competitive peptides mimicking the loop between helices C and D of PAI-2 identified Gln 83 and 86 as residues important in cross-linking. This study defines a mechanism by which PAI-2 is localized to fibrin, where it acts as an effective inhibitor of u-PA-mediated fibrinolysis.


 



Correspondence to:

Helen Ritchie, PhD
Dept of Molecular and Cell Biology
University of Aberdeen
Institute of Medical Sciences
Aberdeen, Scotland, UK, AB25 2ZD
Phone: +44-1224-681818 ext 54575   
Fax: +44-1224-273144