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Dom34‐Hbs1 mediated dissociation of inactive 80S ribosomes promotes restart of translation after stress

Antonia M G van den Elzen, Anthony Schuller, Rachel Green, Bertrand Séraphin

Author Affiliations

  1. Antonia M G van den Elzen1,
  2. Anthony Schuller2,
  3. Rachel Green2 and
  4. Bertrand Séraphin*,1
  1. 1Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) Centre National de Recherche Scientifique (CNRS) UMR 7104/Institut National de Santé et de Recherche Médicale (INSERM) U964/Université de Strasbourg, Illkirch, France
  2. 2Department of Molecular Biology and Genetics, Howard Hughes Medical Institute Johns Hopkins University School of Medicine, Baltimore, MD, USA
  1. *Corresponding author. Tel.: +33 3 88 65 33 36; Fax: +33 3 88 65 33 37; E‐mail: seraphin{at}igbmc.fr
  1. Author contributions

    AMGvdE performed all the in vivo experiments, as well as the in vitro translation, with input from BS. In vitro analyses of ribosome dissociation were performed by AS and AMGvdE with input from RG and BS. BS supervised the project. AMGvdE, AS, RG and BS wrote the manuscript.

Abstract

Following translation termination, ribosomal subunits dissociate to become available for subsequent rounds of protein synthesis. In many translation‐inhibiting stress conditions, e.g. glucose starvation in yeast, free ribosomal subunits reassociate to form a large pool of non‐translating 80S ribosomes stabilized by the ‘clamping’ Stm1 factor. The subunits of these inactive ribosomes need to be mobilized for translation restart upon stress relief. The Dom34‐Hbs1 complex, together with the Rli1 NTPase (also known as ABCE1), have been shown to split ribosomes stuck on mRNAs in the context of RNA quality control mechanisms. Here, using in vitro and in vivo methods, we report a new role for the Dom34‐Hbs1 complex and Rli1 in dissociating inactive ribosomes, thereby facilitating translation restart in yeast recovering from glucose starvation stress. Interestingly, we found that this new role is not restricted to stress conditions, indicating that in growing yeast there is a dynamic pool of inactive ribosomes that needs to be split by Dom34‐Hbs1 and Rli1 to participate in protein synthesis. We propose that this provides a new level of translation regulation.

Synopsis

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Stresses such as glucose starvation generate inactive 80S ribosome complexes. Dom34‐Hbs1 together with Rli1 actively dissociate and re‐activate these complexes, offering a new level of translational control.

  • Non‐translating 80S ribosomes accumulating under stress conditions are actively dissociated into 40S and 60S subunits by the termination factor‐like complex Dom34‐Hbs1 and NTPase Rli1.

  • By making ribosomal subunits available for polypeptide synthesis, splitting of inactive ribosomes by Dom34‐Hbs1 is important for recovery from translation inhibiting stress.

  • By controlling ribosomal subunit availability, Dom34‐Hbs1 also modulates translation in non‐stressed cells.

Footnotes

  • Conflict of interest

    The authors declare that they have no conflict of interest.

  • Received June 28, 2013.
  • Revision received October 14, 2013.
  • Accepted October 30, 2013.

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