title: Signal transduction through extracellular signal-regulated kinase-like pp57 blocked in differentiated colon carcinoma cells having low levels of c-src kinase.
abstract: Basic fibroblast growth factor (FGF) induced a rapid increase in tyrosine phosphorylation of a 57-kDa cytoplasmic protein with functional myelin basic protein kinase activity and antigenic properties common to mitogen-activated kinases or extracellular signal-regulated kinases. Basic and acidic FGFs and the diacylglycerol diolein used the same signal transduction pathway to activate pp57. These FGFs, like diolein (Lee, H., Ghose-Dastidar, J., Winawer, S., and Friedman, E. (1993) J. Biol. Chem., 268, 5255-5263), increased the cellular concentration of long-chain diacylglycerols within the same short time period as they increased pp57 tyrosine phosphorylation. Both FGF and diolein increased phosphorylation of pp57 on the same V8 protease-generated fragments, suggesting a common pathway for the phosphorylation of pp57. FGF-induced signal transduction through pp57 mitogen-activated kinase led to cell growth in two undifferentiated colon carcinoma cell lines. In contrast, basic FGF neither increased tyrosine phosphorylation of pp57 nor increased cell growth in two colon goblet cell differentiated lines derived from the same parental line as the undifferentiated cells. Both goblet cell lines exhibited levels of protein-tyrosine kinase activity about one-fifth that of the undifferentiated lines. The decrease in tyrosine kinase activity was not due to down-regulation of FGF receptors or their tyrosine kinase activities. c-src kinase-specific activity was decreased 4-5-fold in both goblet cell lines, suggesting a role for c-src in pp57-mediated signal transduction.
authors.affiliation: Laboratory of Gastrointestinal Tumor Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Hsu
authors.forename: S
authors.initials: S
authors.lastname: Winawer
authors.forename: E
authors.initials: E
authors.lastname: Friedman
mesh_terms: D000081247:CSK Tyrosine-Protein Kinase; D002454:Cell Differentiation; D002999:Clone Cells; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000235:genetics; D004075:Diglycerides / Q000494:pharmacology*; D016220:Fibroblast Growth Factor 1 / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D016391:Genes, src; D038362:Glycogen Synthase Kinase 3; D006801:Humans; D007700:Kinetics; D008970:Molecular Weight; D011494:Protein Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
chemical_list: D004075:Diglycerides; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; C000631346:CSK protein, human; D038362:Glycogen Synthase Kinase 3; C013965:diolein