Regulatory role of major tyrosine autophosphorylation site of kinase domain of c-Met receptor (scatter factor/hepatocyte growth factor receptor).
Ligand-induced tyrosine kinase activation of the scatter factor/hepatocyte growth factor receptor (c-Met) is thought to be essential for the biological responses of target cells. To assess the regulatory role of the major tyrosine autophosphorylation site (tyrosine 1233) of the mouse c-Met receptor in the tyrosine kinase activation of the receptor, we constructed a mutant receptor in which the tyrosine residue was replaced with phenylalanine. When the cells expressing the mutant receptor were incubated with the ligand, no biological responses were observed, and the level of tyrosine phosphorylation of the receptor was very low compared with that of the wild-type receptor. The in vitro kinase activity of the mutant receptor toward an exogenous substrate and the receptor itself was also low. Furthermore, tyrosine phosphorylation of the cellular proteins by ligand stimulation was not detected in intact cells expressing the mutant receptor. The low level of kinase activity and the lack of biological activity of the mutant receptor indicate that the major autophosphorylation site positively regulates the tyrosine kinase of the c-Met receptor and phosphorylation of cellular substrates in the scatter factor/hepatocyte growth factor signaling pathway.
Komada
M
M
Institute for Liver Research, Kansai Medical University, Osaka, Japan.
Kitamura
N
N
D000818:Animals; D001483:Base Sequence; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D008969:Molecular Sequence Data; D004676:Myelin Basic Protein / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism*
D008024:Ligands; D004676:Myelin Basic Protein; D011993:Recombinant Fusion Proteins; D014443:Tyrosine; D004815:Epidermal Growth Factor; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases