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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP-Binding Cassette Transporters / genetics
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ATP-Binding Cassette Transporters / metabolism*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Endoribonucleases / genetics
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Endoribonucleases / metabolism*
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GTP-Binding Proteins / genetics
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GTP-Binding Proteins / metabolism*
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Glucose / metabolism
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HSP70 Heat-Shock Proteins / genetics
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HSP70 Heat-Shock Proteins / metabolism*
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Peptide Elongation Factors / genetics
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Peptide Elongation Factors / metabolism*
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Polyribosomes / metabolism
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Protein Biosynthesis*
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Ribosome Subunits / metabolism
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Ribosomes / metabolism*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Sequence Deletion
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Stress, Physiological
Substances
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ATP-Binding Cassette Transporters
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Cell Cycle Proteins
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DNA-Binding Proteins
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HBS1 protein, S cerevisiae
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HSP70 Heat-Shock Proteins
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Peptide Elongation Factors
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RLI1 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Stm1 protein, S cerevisiae
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Dom34 protein, S cerevisiae
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Endoribonucleases
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GTP-Binding Proteins
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Glucose