Src-dependence and pertussis-toxin sensitivity of urokinase receptor-dependent chemotaxis and cytoskeleton reorganization in rat smooth muscle cells.
The catalytically inactive precursor of urokinase-type plasminogen activator (pro-u-PA) induced a chemotactic response in rat smooth muscle cells (RSMC) through binding to the membrane receptor of urokinase (u-PA receptor [u-PAR]). A soluble form of u-PAR activated by chymotrypsin cleavage as well as a peptide located between domain 1 and 2 of u-PAR reproduced the effect of pro-u-PA on cell migration. The chemotactic pro-u-PA effect correlates with a dramatic reorganization of actin cytoskeleton, of adhesion plaques, and with major cell shape changes in RSMC. Pro-u-PA induced a decrease in stress fiber content, membrane ruffling, actin ring formation, and disruption leading to the characteristic elongated cell shape of motile cells with an actin semi-ring located close to the leading edge of cells. u-PAR effects on both chemotaxis and cytoskeleton were sensitive to pertussis toxin and, hence, possibly require G proteins. u-PAR effects are accompanied by a relocation of u-PAR, vitronectin receptor (VNR) alphavbeta3, beta1 integrin subunit, and Src tyrosine kinase to the leading membrane of migrating cells. In conclusion, our data show that pro-u-PA, via binding to u-PAR, controls a signaling pathway, regulated by tyrosine kinases and possibly G proteins, leading to cell cytoskeleton reorganization and cell migration.
Degryse
B
B
DIBIT, Università Vita-Salute San Raffaele, Milano, Italy; McGill University and Royal Victoria Hospital, Montreal, Quebec, Canada.
Resnati
M
M
Rabbani
S A
SA
Villa
A
A
Fazioli
F
F
Blasi
F
F
D000199:Actins / Q000032:analysis; D000818:Animals; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects*; D003599:Cytoskeleton / Q000187:drug effects* / Q000648:ultrastructure; D004792:Enzyme Precursors / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000494:pharmacology; D037342:Pertussis Toxin; D011487:Protein Conformation; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology; D051381:Rats; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000502:physiology*; D055293:Receptors, Urokinase Plasminogen Activator; D019030:Receptors, Vitronectin / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D019061:src-Family Kinases / Q000502:physiology*
D000199:Actins; D004792:Enzyme Precursors; D010446:Peptide Fragments; C524899:Plaur protein, mouse; C524900:Plaur protein, rat; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D019030:Receptors, Vitronectin; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; D014568:Urokinase-Type Plasminogen Activator; D019204:GTP-Binding Proteins; C067551:saruplase