A novel, specific pro-urokinase complex on monocyte-like cells, detected by transglutaminase-catalyzed cross-linking.
Radiolabeled pro-urokinase plasminogen activator (pro-uPA) was cross-linked to a specific protein on the surface of human monocyte-like U937 cells in a reaction catalyzed by tissue transglutaminase. The conjugate formed with this unknown component had a much higher molecular weight (apparent M(r) 250,000-300,000) than the complex of pro-uPA and the urokinase plasminogen activator receptor (uPAR). There was a strong preference for the pro-form of uPA. The conjugate was recognized by antibodies against uPA but not by anti-uPAR antibodies. Nevertheless, the blocking of uPAR with a monoclonal antibody abolished the formation of the conjugate, thus showing a role of uPAR in this process.
Behrendt
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Finsen Laboratory, Righospitalet, Copenhagen, Denmark.
Rønne
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Danø
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D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse; D008970:Molecular Weight; D009000:Monocytes / Q000201:enzymology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D011503:Transglutaminases / Q000302:isolation & purification / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*
D003432:Cross-Linking Reagents; C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D011503:Transglutaminases; D014568:Urokinase-Type Plasminogen Activator; C067551:saruplase