title: Activation of p38 MAP-kinase and caldesmon phosphorylation are essential for urokinase-induced human smooth muscle cell migration.
abstract: We have explored intracellular pathways involved in the urokinase type plasminogen activator (urokinase or uPA)-stimulated migration of human airway smooth muscle cells (hAWSMC). Using a set of uPA mutants we found that protease activity, growth factor-like and kringle domains of uPA differentially contribute to activation of p42/p44erk1,2 and p38 MAP-kinases. Consistent with our earlier data [Mukhina et al., J. Biol. Chem. 275 (2000), 16450-16458], the kringle domain of uPA was sufficient and required to stimulate cell motility. Here we report that uPA mutants containing the kringle domain specifically activate the p38 MAP-kinase pathway and actomyosin by increasing phosphorylation of the critical Ser-19 on the myosin regulatory light chain and MAP-kinase sites of the actin-associated regulatory protein caldesmon. While pharmacological inhibition of p38 MAP-kinase activation did not affect myosin light chain phosphorylation, it blocked the increase in caldesmon phosphorylation and uPA-stimulated migration of hAWSMC on a collagen-coated surface. We conclude that activation of p38 MAP-kinase and downstream phosphorylation of non-muscle caldesmon is essential for urokinase-stimulated smooth muscle cell migration.
authors.affiliation: Laboratory of Cell Motility, Institute of Experimental Cardiology, Russian Cardiology Research Center, Moscow.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Goncharova
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Vorotnikov
authors.forename: Elena O
authors.initials: EO
authors.lastname: Gracheva
authors.forename: C L Albert
authors.initials: CL
authors.lastname: Wang
authors.forename: Reynold A
authors.initials: RA
authors.lastname: Panettieri
authors.forename: Victoria V
authors.initials: VV
authors.lastname: Stepanova
authors.forename: Vsevolod A
authors.initials: VA
authors.lastname: Tkachuk
mesh_terms: D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D006801:Humans; D018082:Kringles / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D014132:Trachea / Q000166:cytology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002148:Calmodulin-Binding Proteins; D011994:Recombinant Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D014568:Urokinase-Type Plasminogen Activator