Involvement of Ras and Ral in chemotactic migration of skeletal myoblasts.
In skeletal myoblasts, Ras has been considered to be a strong inhibitor of myogenesis. Here, we demonstrate that Ras is involved also in the chemotactic response of skeletal myoblasts. Expression of a dominant-negative mutant of Ras inhibited chemotaxis of C2C12 myoblasts in response to basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), and insulin-like growth factor 1 (IGF-1), key regulators of limb muscle development and skeletal muscle regeneration. A dominant-negative Ral also decreased chemotactic migration by these growth factors, while inhibitors for phosphatidylinositol 3-kinase and mitogen-activated protein kinase kinase (MEK) showed no effect. Activation of the Ras-Ral pathway by expression of an activated mutant of either Ras, the guanine-nucleotide dissociation stimulator for Ral, or Ral resulted in increased motility of myoblasts. The ability of Ral to stimulate motility was reduced by introduction of a mutation which prevents binding to Ral-binding protein 1 or phospholipase D. These results suggest that the Ras-Ral pathway is essential for the migration of myoblasts. Furthermore, we found that Ras and Ral are activated in C2C12 cells by bFGF, HGF and IGF-1 and that the Ral activation is regulated by the Ras- and the intracellular Ca(2+)-mediated pathways. Taken together, our data indicate that Ras and Ral regulate the chemotactic migration of skeletal muscle progenitors.
Suzuki
J
J
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8501, Japan.
Yamazaki
Y
Y
Li
G
G
Kaziro
Y
Y
Koide
H
H
Guang
L
L
D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D002867:Chromones / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000378:metabolism; D011905:Genes, ras; D006133:Growth Substances / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D048728:MAP Kinase Kinase Kinase 1; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D020725:ral GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
D002070:Butadienes; D000001:Calcimycin; D002118:Calcium; D002867:Chromones; D004533:Egtazic Acid; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D006133:Growth Substances; D007334:Insulin-Like Growth Factor I; D007544:Isopropyl Thiogalactoside; D048728:MAP Kinase Kinase Kinase 1; D009025:Morpholines; D009570:Nitriles; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D020725:ral GTP-Binding Proteins; D018631:ras Proteins; C113580:U 0126; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C482578:Map3k1 protein, mouse