Asunto(s)
Plaquetas/fisiología , Calcio/metabolismo , Agregación Plaquetaria/fisiología , Activador de Plasminógeno de Tipo Uroquinasa/metabolismo , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Activación Enzimática , Humanos , Técnicas In Vitro , Líquido Intracelular/metabolismo , Agregación Plaquetaria/efectos de los fármacos , Proteínas Recombinantes/farmacología , Activador de Plasminógeno de Tipo Uroquinasa/farmacologíaRESUMEN
Urokinase type plasminogen activator (uPA) converts plasminogen to plasmin and is highly chemotactic for many cell types. We examined, using recombinant wild type and mutated forms of uPA, the extent to which its proteolytic properties, its growth-like domain (GFD) and/or interactions with the specific receptor (uPAR) contribute to the chemotactic activity towards vascular smooth muscle cells (SMC). Recombinant wild type uPA (r-uPA) stimulated cell migration nearly 5.8-fold, inactive r-uPA, with a mutation in the catalitic domain (r-uPA(H/Q)), 3-fold, uPA without growth factor like domain (r-uPA(GFD )), 2.6-fold, and a form containing both mutations (r-uPA(H/Q, GFD ), 3.3-fold. All recombinant forms of uPA, wild type and those with mutations were equally and highly effective (IC50 approximately 20 nM) in displacing 125I-r-uPA bound to SMC. These results indicate that additional mechanisms, not dependent on uPA's proteolytic activity or the binding ability of its GFD to uPAR, are the major contributors to its chemotactic action on SMC.
Asunto(s)
Quimiotaxis/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/patología , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Animales , Sitios de Unión/genética , Unión Competitiva , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Mutación , Ratas , Receptores de Superficie Celular/metabolismo , Receptores del Activador de Plasminógeno Tipo Uroquinasa , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacología , Activador de Plasminógeno de Tipo Uroquinasa/química , Activador de Plasminógeno de Tipo Uroquinasa/genéticaRESUMEN
Urokinase activates adhesion of monocytic U937 cells to fibrinogen-coated surface. This effect is due to urokinase proteolytic activity and does not depend on the urokinase binding to its receptor.