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Inappropriate translation inhibition and P-body formation cause cold-sensitivity in tryptophan-auxotroph yeast mutants

  • Authors: Ballester-Tomás L, Prieto JA, Alepuz P, González A, Garre E, Randez-Gil F.
  • (2017).
  • Publication types: Article
  • URL Publication: Inappropriate translation inhibition and P-body formation cause cold-sensitivity in tryptophan-auxotroph yeast mutants
  • Publication Title (name of the book or magazine): Molecular Cell Research.
  • No.Volume 1864, Issue 2, February 2017, Pages 314-323

  • Abstract:

    [Biochimica et Biophysica Acta (BBA)]. In response to different adverse conditions, most eukaryotic organisms, including Saccharomyces cerevisiae, downregulate protein synthesis through the phosphorylation of eIF2α (eukaryotic initiation factor 2α) by Gcn2, a highly conserved protein kinase. Gcn2 also controls the translation of Gcn4, a transcription factor involved in the induction of amino acid biosynthesis enzymes. Here, we have studied the functional role of Gcn2 and Gcn2-regulating proteins, in controlling translation during temperature downshifts of TRP1 and trp1 yeast cells. Our results suggest that neither cold-instigated amino acid limitation nor Gcn2 are involved in the translation suppression at low temperature. However, loss of TRP1 causes increased eIF2α phosphorylation, Gcn2-dependent polysome disassembly and overactivity of Gcn4, which result in cold-sensitivity. Indeed, knock-out of GCN2 improves cold growth of trp1 cells. Likewise, mutation of several Gcn2-regulators and effectors results in cold-growth effects. Remarkably, we found that Hog1, the osmoresponsive MAPK, plays a role in the regulatory mechanism of Gcn2-eIF2α. Finally, we demonstrated that P-body formation responds to a downshift in temperature in a TRP1-dependent manner and is required for cold tolerance.

  • Highlights

    • Cold results in eIF2α phosphorylation and Gcn2-independent polysome disassembly.
    • Loss of TRP1 increases these effects, which correlates with cold sensitivity.
    • Knock-out of GCN2 improves cold growth of trp1 cells.
    • The MAPK Hog1 plays a role in the regulatory mechanism of Gcn2-eIF2α.
    • P-body formation response is required for cold tolerance.
    DOI: 10.1016/j.bbamcr.2016.11.012