Elongator's toxin-target (TOT) function is nuclear localization sequence dependent and suppressed by

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Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance
10:41

Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance

Published on: January 3, 2012

Lars Fichtner1, Daniel Jablonowski, Angelika Schierhorn

  • 1Biologicum, Institut für Genetik, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 10, D-06120 Halle (Saale), Germany.

Molecular Microbiology
|August 28, 2003
PubMed

Insights

The Elongator complex

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The Elongator complex in Saccharomyces cerevisiae is crucial for the toxin target (TOT) function.
  • This function is essential for Kluyveromyces lactis zymocin to induce cell cycle arrest.
  • Post-translational modification and proteolysis of Elongator subunit Tot1p (Elp1p) impact its TOT function.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying the Elongator complex's toxin target (TOT) function.
  • To identify proteins interacting with the Elongator complex and their role in zymocin-induced cell cycle arrest.
  • To elucidate the role of nuclear import in Elongator's TOT function.

Main Methods:

  • TAP tagging to identify protein interactions.
  • Analysis of gene deletions affecting Elongator modification and function.
  • Localization studies using green fluorescent protein (GFP) fusions and nuclear localization sequences (NLS).

Main Results:

  • Loss of ubiquitin-related system (URM1-UBA4) and KTI11 leads to increased Tot1p modification/proteolysis and abrogates TOT function.
  • Kti11p interacts with Elongator and translational proteins, suggesting a role in toxin response.
  • Loss of YIL103w and DPH2 suppresses zymocin toxicity, indicating overlapping pathways mediated by Kti11p.
  • Unmodified Tot1p is found in a complex with RNA polymerase II (pol II) and nucleolin.
  • Elongator's nuclear import via NLS and karyopherin-dependent import is essential for its TOT function.

Conclusions:

  • Post-translational modification and proteolysis of Elongator may regulate its association with pol II and cellular localization.
  • The Elongator complex's toxin target (TOT) function is dependent on its nuclear import pathway.
  • Kti11p acts as a scaffold, linking Elongator to translational machinery and potentially mediating overlapping toxin response pathways.

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