Protein Kinase C Phosphorylates Ribosomal Protein S6 Kinase βII and Regulates Its Subcellular Localization
| Autor: | Mong-Lien Wang, Taras Valovka, Alexander Lutsyk, Rainer Cramer, Tim R. Fenton, Ivan Gout, Valeriy Filonenko, Frederique Verdier, Christopher G. Proud, Heike Rebholz, Miechyslav Gzhegotsky, Lijun Wang, Genadiy Matsuka, Alexander Zhyvoloup, Peter J. Parker |
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| Rok vydání: | 2003 |
| Předmět: |
Molecular Sequence Data
Active Transport Cell Nucleus P70-S6 Kinase 1 In Vitro Techniques Mitogen-activated protein kinase kinase Biology Transfection Cell Line MAP2K7 Phenylephrine Humans Insulin ASK1 Amino Acid Sequence Phosphorylation Protein kinase A Cell Growth and Development Molecular Biology Protein Kinase C Binding Sites MAP kinase kinase kinase Cyclin-dependent kinase 2 Ribosomal Protein S6 Kinases 70-kDa Cell Biology Recombinant Proteins Cell biology Isoenzymes Biochemistry Fatty Acids Unsaturated biology.protein Tetradecanoylphorbol Acetate Cyclin-dependent kinase 9 Mitogens Signal Transduction Subcellular Fractions |
| Zdroj: | Molecular and Cellular Biology. 23:852-863 |
| ISSN: | 1098-5549 |
| Popis: | The ribosomal protein S6 kinase (S6K) belongs to the AGC family of Ser/Thr kinases and is known to be involved in the regulation of protein synthesis and the G(1)/S transition of the cell cycle. There are two forms of S6K, termed S6Kalpha and S6Kbeta, which have cytoplasmic and nuclear splice variants. Nucleocytoplasmic shuttling has been recently proposed for S6Kalpha, based on the use of the nuclear export inhibitor, leptomycin B. However, the molecular mechanisms regulating subcellular localization of S6Ks in response to mitogenic stimuli remain to be elucidated. Here we present data on the in vitro and in vivo phosphorylation of S6Kbeta, but not S6Kalpha, by protein kinase C (PKC). The site of phosphorylation was identified as S486, which is located within the C-terminal nuclear localization signal. Mutational analysis and the use of phosphospecific antibodies provided evidence that PKC-mediated phosphorylation at S486 does not affect S6K activity but eliminates the function of its nuclear localization signal and causes retention of an activated form of the kinase in the cytoplasm. Taken together, this study uncovers a novel mechanism for the regulation of nucleocytoplasmic shuttling of S6KbetaII by PKC-mediated phosphorylation. |
| Databáze: | OpenAIRE |
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