title: PAI-1 inhibits urokinase-induced chemotaxis by internalizing the urokinase receptor.
abstract: PAI-1 (plasminogen activator inhibitor-1) binds the urokinase-type plasminogen activator (uPA) and causes its degradation via its receptor uPAR and low-density lipoprotein receptor-related protein (LRP). While both uPA and PAI-1 are chemoattractants, we find that a preformed uPA-PAI-1 complex has no chemotactic activity and that PAI-1 inhibits uPA-induced chemotaxis. The inhibitory effect of PAI-1 on uPA-dependent chemotaxis is reversed when uPAR internalization is inhibited by the 39 kDa receptor-associated protein or by anti-LRP antibodies. Under the same conditions, the uPA-PAI-1 complex is turned into a chemoattractant causing cytoskeleton reorganization and extracellular-regulated kinase/mitogen-activated protein kinases activation. Thus, uPAR internalization by PAI-1 regulates cell migration.
authors.affiliation: Molecular Genetics Unit, DIBIT, Department of Cell Biology and Functional Genetics, University Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Degryse
authors.forename: C F
authors.initials: CF
authors.lastname: Sier
authors.forename: M
authors.initials: M
authors.lastname: Resnati
authors.forename: M
authors.initials: M
authors.lastname: Conese
authors.forename: F
authors.initials: F
authors.lastname: Blasi
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured; D002633:Chemotaxis; D003599:Cytoskeleton / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008024:Ligands; D020935:MAP Kinase Signaling System; D051379:Mice; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
chemical_list: D008024:Ligands; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; C524899:Plaur protein, mouse; C524900:Plaur protein, rat; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D020928:Mitogen-Activated Protein Kinases; D014568:Urokinase-Type Plasminogen Activator