Biochemical importance of glycosylation of plasminogen activator inhibitor-1

Thromb Haemost. 2003 Aug;90(2):206-17. doi: 10.1160/TH03-01-0034.

Abstract

The serpin plasminogen activator inhibitor-1 (PAI-1) is a potential target for anti-thrombotic and anti-cancer therapy. PAI-1 has 3 potential sites for N-linked glycosylation. We demonstrate here that PAI-1 expressed recombinantly or naturally by human cell lines display a heterogeneous glycosylation pattern of the sites at N209 and N265, while that at N329 is not utilised. The IC(50)-values for inactivation of PAI-1 by 4 monoclonal antibodies differed strongly between glycosylated PAI-1 and non-glycosylated PAI-1 expressed in E. coli. For 3 antibodies, an overlap of the epitopes with the glycosylation sites could be excluded as explanation for the differential reactivity. The latency transition of non-glycosylated, but not of glycosylated PAI-1, was strongly accelerated by a non-ionic detergent. The different biochemical properties of glycosylated and non-glycosylated PAI-1 depended specifically on glycosylation of either one or the other of the utilised sites. The PAI-1-binding protein vitronectin reversed the changes associated with the lack of glycosylation at one of the sites. Our results stress the importance of the source of PAI-1 when studying the mechanisms of action of PAI-1-inactivating compounds of potential clinical importance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Cell Line
  • Detergents / pharmacology
  • Genetic Variation
  • Glycosylation*
  • Half-Life
  • Humans
  • Molecular Structure
  • Octoxynol / pharmacology
  • Plasminogen Activator Inhibitor 1 / chemistry
  • Plasminogen Activator Inhibitor 1 / immunology
  • Plasminogen Activator Inhibitor 1 / metabolism*
  • Vitronectin / pharmacology

Substances

  • Antibodies, Monoclonal
  • Detergents
  • Plasminogen Activator Inhibitor 1
  • Vitronectin
  • Octoxynol