Phosphatidylinositol 3′-Kinase-independent p70 S6 Kinase Activation by Fibroblast Growth Factor Receptor-1 Is Important for Proliferation but Not Differentiation of Endothelial Cells
| Autor: | Richard J. Woodfield, Michael J.O. Wakelam, George Thomas, Matthew Hodgkin, Lena Claesson-Welsh, Shigeru Kanda |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Bisindolylmaleimide
Polyenes Protein Serine-Threonine Kinases Biology Fibroblast growth factor Biochemistry Wortmannin Mice Phosphatidylinositol 3-Kinases chemistry.chemical_compound Animals Receptor Fibroblast Growth Factor Type 1 Phosphatidylinositol Molecular Biology Cells Cultured Protein kinase C Sirolimus Dose-Response Relationship Drug Phospholipase C gamma Kinase Muscles Ribosomal Protein S6 Kinases Fibroblast growth factor receptor 1 Brain Receptor Protein-Tyrosine Kinases Cell Differentiation Cell Biology Receptors Fibroblast Growth Factor Rats Cell biology Enzyme Activation Isoenzymes Phosphotransferases (Alcohol Group Acceptor) chemistry Type C Phospholipases Mutation Fibroblast Growth Factor 2 Endothelium Vascular Signal transduction Cell Division Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 272:23347-23353 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.272.37.23347 |
| Popis: | p70(s6k) has a role in cell cycle progression in response to specific extracellular stimuli. The signal transduction pathway leading to activation of p70(s6k) by fibroblast growth factor receptor-1 (FGFR-1) was examined in FGF-2-treated rat L6 myoblasts. p70(s6k) was activated in a biphasic and rapamycin-sensitive manner. Although phosphatidylinositol 3'-kinase was not activated in the FGF-2 treated cells, as judged from in vitro and in vivo analyses, wortmannin and LY294002 treatment inhibited p70(s6k) activation. Inhibition of protein kinase C (PKC), by bisindolylmaleimide or by chronic phorbol ester treatment of the FGFR-1 cells, suppressed but did not block p70(s6k) activation. In cells expressing a point-mutated FGFR-1, Y766F, unable to mediate PKC activation, p70(s6k) was still activated, in a bisindolylmaleimide- and phorbol ester-resistant manner. The involvement of S6 kinase in FGFR-1-dependent biological responses was examined in murine brain endothelial cells. In response to FGF-2, these cells differentiate to form tube-like structures in collagen gel cultures and proliferate when cultured on fibronectin. p70(s6k) was not activated in endothelial cells on collagen, whereas activation was observed during proliferation on fibronectin. In agreement with this finding, rapamycin inhibited the proliferative but not the differentiation response. Our results indicate that FGFR-1 mediates p70(s6k) activation by a phosphatidylinositol 3'-kinase-independent mechanism that does not require PKC activation and, furthermore, proliferation, but not differentiation of endothelial cells in response to FGF-2, is associated with p70(s6k) activation. |
| Databáze: | OpenAIRE |
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