title: Prion protein stimulates tissue-type plasminogen activator-mediated plasmin generation via a lysine-binding site on kringle 2.
abstract: Recombinant human prion-protein (PrP23-231) stimulates plasminogen activation by tissue-type plasminogen activator (t-PA). The stimulatory activity is conserved in the N-terminal fragment (PrP23-110). It has further been shown by others that PrP(c) binds to kringle-domains of plasminogen. We compared the stimulatory activity of recombinant PrP23-231 and PrP23-110 on plasminogen activation catalyzed by t-PA, urokinase (u-PA), streptokinase and Desmodus salivary plasminogen activator (DSPAalpha1). As these plasminogen activators are distinct, with respect to their kringle domains we studied their binding to immobilized PrP23-110. Plasminogen activation was measured in a chromogenic assay in vitro and binding studies were carried out using surface plasmon resonance technology. We found that recombinant full-length prion protein, PrP23-231, and PrP23-110 specifically stimulate t-PA mediated plasminogen activation. Two hundred nanomoles per liter of PrP23-110 stimulated 1.8 nmol L(-1) t-PA 48-fold, 180 nmol L(-1) DSPA(alpha1) 2.5-fold, 1.8 nmol L(-1) u-PA 1.1-fold, and 1.8 nmol L(-1) streptokinase 1.8-fold. Our data show no specific binding for streptokinase. In contrast all plasminogen activators carrying a kringle domain bound to PrP23-110. We further studied the effect of lysine on binding to PrP23-110 and on plasminogen activation by DSPA(alpha1) or t-PA. Lysine decreased both the binding of t-PA to PrP23-110 and the stimulation of plasmin generation by t-PA. Both binding and plasminogen activation of DSPA(alpha1) were not influenced by the presence of lysine. All plasminogen activators tested bearing kringle domains bind to PrP23-110. Binding to PrP23-110 is not sufficient for stimulation of plasmin generation. Thus the lysine-binding site of kringle 2 that is unique to t-PA appears to mediate the specific stimulation of plasminogen activation by the cellular prion protein.
authors.affiliation: Institut für Laboratoriumsmedizin und Pathobiochemie, Charité, Berlin, Medizinische Fakultät der Humboldt Universität zu Berlin, Berlin, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Epple
authors.forename: Wolf-Dieter
authors.initials: WD
authors.lastname: Schleuning
authors.forename: Gerhard
authors.initials: G
authors.lastname: Kettelgerdes
authors.forename: Eckart
authors.initials: E
authors.lastname: Kottgen
authors.forename: Reinhard
authors.initials: R
authors.lastname: Gessner
authors.forename: Michael
authors.initials: M
authors.lastname: Praus
mesh_terms: D001665:Binding Sites; D005341:Fibrinolysin / Q000096:biosynthesis*; D006801:Humans; D018082:Kringles; D008239:Lysine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D010958:Plasminogen / Q000378:metabolism; D011328:Prions / Q000494:pharmacology*; D011485:Protein Binding; D010959:Tissue Plasminogen Activator / Q000737:chemistry* / Q000502:physiology*
chemical_list: D010446:Peptide Fragments; D011328:Prions; C495134:prion protein (23-110); C428437:prion protein (23-231); D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D008239:Lysine