Thromb Haemost 2000; 84(01): 71-77
DOI: 10.1055/s-0037-1613970
Commentary
Schattauer GmbH

Plasminogen Binding Properties of Macrophage Inflammatory Protein (MIP)-2α

Begoña Arza
1   From the Institut de Recerca Oncològica (IRO), Hospital Duran i Reynals, Barcelona, Spain, Belgium
2   Center for Molecular and Vascular Biology, University of Leuven, Belgium
,
Jordi Félez
1   From the Institut de Recerca Oncològica (IRO), Hospital Duran i Reynals, Barcelona, Spain, Belgium
,
Pere Fábregas
1   From the Institut de Recerca Oncològica (IRO), Hospital Duran i Reynals, Barcelona, Spain, Belgium
,
Yves Laroche
3   Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, Leuven, Belgium
,
Désiré Collen
2   Center for Molecular and Vascular Biology, University of Leuven, Belgium
3   Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, Leuven, Belgium
,
Roger H. Lijnen
2   Center for Molecular and Vascular Biology, University of Leuven, Belgium
› Author Affiliations

This study was supported by research grants from the Fundación Ramón Areces; SCS Generalitat de Catalunya; Marató TV3-Cardiovascular; CIRIT:1998BEAI200014, and from the Flemish Fund for Scientific Research (FWO, contract G.0138.00).
Further Information

Publication History

Received 17 November 1999

Accepted after resubmission 24 February 2000

Publication Date:
10 December 2017 (online)

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Summary

The chemokine macrophage inflammatory protein (MIP)-2α was identified as a plasminogen binding protein by phage display analysis. MIP-2α and a truncated form lacking 5 lysine residues in the COOHterminal region (mut-MIP-2α) were expressed in E. coli and purified to apparent homogeneity. Purified MIP-2α but not mut-MIP-2α bound specifically to plasminogen, with KA of 3.7×105 M−1 for the interaction of plasminogen with surface-bound MIP-2α. Binding and competition experiments indicated that the interaction involves the region comprising the first 3 kringles of plasminogen and the COOH-terminal lysine-rich domain of MIP-2α. Activation of plasminogen bound to surface-associated MIP-2α by two-chain urokinase-type plasminogen activator (tcu-PA) was about 2.5-fold more efficient than in solution (catalytic efficiency kcat/KM of 0.1 µM−1s−1, as compared to 0.04 µM−1s−1). In contrast, binding of plasminogen to MIP-2α in solution was very weak, as evidenced by the absence of competition of MIP-2α with lysine-Sepharose or with human THP-1 cells for binding of plasminogen. In agreement with this finding, addition of excess MIP-2α did not affect the main functional properties of plasmin(ogen) in solution, as indicated by unaltered activation rates of plasminogen by tcu-PA or tissuetype plasminogen activator (t-PA), t-PA-mediated fibrinolysis, and inhibition rate of plasmin by α2-antiplasmin. Thus, association of MIP-2α with surfaces exposes its COOH-terminal plasminogen-binding site, and may result in enhanced local plasmin generation.

Parts of this study were presented at the ETRO/EUROCONFERENCE on Receptors in Fibrinolysis (Leiden, The Netherlands, 1997), at the XIII Congreso de la Sociedad Española de Trombosis y Hemostasia (Barcelona, Spain, 1997), and at the VIth International Workshop on Molecular and Cellular Biology of Plasminogen Activation (San Diego, USA, 1997).