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From a Natural Product to Its Biosynthetic Gene Cluster: A Demonstration Using Polyketomycin from Streptomyces diastatochromogenes Tü6028
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The marine polyketide myriaporone 3/4 stalls translation by targeting the elongation phase

Yazh Muthukumar1, Myriam Roy, Aruna Raja

  • 1Department of Chemical Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.

Chembiochem : a European Journal of Chemical Biology
|January 11, 2013
PubMed

Insights

Myriaporone 3/4 inhibits eukaryotic protein synthesis by stalling translation elongation. This occurs through direct binding to eukaryotic elongation factor 2 kinase, leading to factor 2 phosphorylation and reduced endothelial cell tube formation.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Cell Biology

Background:

  • Myriaporone 3/4 is a known cytotoxic polyketide.
  • Its role as an inhibitor of eukaryotic protein synthesis has been documented.
  • The precise mechanism of translation inhibition by myriaporone 3/4 remained unclear.

Purpose of the Study:

  • To elucidate the mechanism by which myriaporone 3/4 inhibits eukaryotic protein synthesis.
  • To investigate the effect of myriaporone 3/4 on endothelial cell function.
  • To assess the differential toxicity of myriaporone 3/4 in various cell types.

Main Methods:

  • Investigated the effect of myriaporone 3/4 on protein synthesis elongation.
  • Examined the phosphorylation status of eukaryotic elongation factor 2 (eEF2).
  • Assessed the binding of myriaporone 3/4 to eukaryotic elongation factor 2 kinase (eEF2K).
  • Evaluated the impact of myriaporone 3/4 on in vitro endothelial cell tube formation.
  • Compared the cytotoxicity of myriaporone 3/4 in primary and tumor cells.

Main Results:

  • Myriaporone 3/4 was found to stall protein synthesis during the elongation phase.
  • This stalling is mediated by the induction of eEF2 phosphorylation.
  • Myriaporone 3/4 directly binds to eEF2K, causing the observed phosphorylation.
  • Inhibition of in vitro endothelial cell tube formation was observed at nanomolar concentrations.
  • Myriaporone 3/4 exhibited significantly lower toxicity towards primary cells compared to tumor cells (at least 300-fold difference).

Conclusions:

  • Myriaporone 3/4 inhibits eukaryotic translation by targeting the eEF2K-eEF2 pathway.
  • The compound demonstrates anti-angiogenic potential by inhibiting endothelial cell tube formation at low, non-cytotoxic concentrations.
  • Myriaporone 3/4 displays a favorable therapeutic window due to its selective toxicity towards tumor cells over primary cells.

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