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p70 S6K1 nuclear localization depends on its mTOR-mediated phosphorylation at T389, but not on its kinase activity

M Rosner1, K Schipany, M Hengstschläger

  • 1Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, 1090, Vienna, Austria.

Amino Acids
|June 29, 2011
PubMed

Insights

The protein kinase p70 S6K1

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The protein kinase p70 S6K1 is crucial in human diseases.
  • Mammalian target of rapamycin (mTOR) activates p70 S6K1 via phosphorylation.
  • p70 S6K1 regulates protein synthesis, cell cycle, growth, and survival.

Purpose of the Study:

  • To determine if p70 S6K1 phosphorylation or kinase activity is essential for its localization.
  • To investigate the role of mTOR-mediated phosphorylation at T389 in p70 S6K1 localization.

Main Methods:

  • Utilized the compound PF-4708671 to selectively inhibit p70 S6K1 kinase activity.
  • Assessed the impact of inhibiting kinase activity on p70 S6K1 phosphorylation at T389.
  • Analyzed the nucleocytoplasmic localization of p70 S6K1 under different conditions.

Main Results:

  • PF-4708671 inhibits p70 S6K1 kinase activity while maintaining T389 phosphorylation.
  • Nucleocytoplasmic localization of p70 S6K1 is dependent on mTOR-mediated phosphorylation at T389.
  • Kinase activity of p70 S6K1 is not essential for its proper subcellular localization.

Conclusions:

  • mTOR-mediated phosphorylation, not kinase activity, dictates p70 S6K1's nucleocytoplasmic localization.
  • These findings enhance understanding of p70 S6K1 regulation and enzyme localization.
  • Provides insights into cellular mechanisms underlying human disease development.

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