title: Biochemical importance of glycosylation of plasminogen activator inhibitor-1.
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.
authors.affiliation: Laboratory of Pharmaceutical Biology and Phytopharmacology, Faculaty of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Gils
authors.forename: Katrine E
authors.initials: KE
authors.lastname: Pedersen
authors.forename: Peter
authors.initials: P
authors.lastname: Skottrup
authors.forename: Anni
authors.initials: A
authors.lastname: Christensen
authors.forename: Dominik
authors.initials: D
authors.lastname: Naessens
authors.forename: Johanna
authors.initials: J
authors.lastname: Deinum
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Enghild
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Declerck
authors.forename: Peter A
authors.initials: PA
authors.lastname: Andreasen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D002460:Cell Line; D003902:Detergents / Q000494:pharmacology; D014644:Genetic Variation; D006031:Glycosylation; D006207:Half-Life; D006801:Humans; D015394:Molecular Structure; D017830:Octoxynol / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D019096:Vitronectin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D003902:Detergents; D017395:Plasminogen Activator Inhibitor 1; D019096:Vitronectin; D017830:Octoxynol