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Hayashi H, Nagai R, Abe T, Wada M, Ito K, Takeuchi-Tomita N. Tight interaction of eEF2 in the presence of Stm1 on ribosome. J Biochem 2018; 163:177-185. [PMID: 29069440 DOI: 10.1093/jb/mvx070] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/07/2017] [Indexed: 11/14/2022] Open
Abstract
The stress-related protein Stm1 interacts with ribosomes, and is implicated in repressing translation. Stm1 was previously studied both in vivo and in vitro by cell-free translation systems using crude yeast lysates, but its precise functional mechanism remains obscure. Using an in vitro reconstituted translation system, we now show that Stm1 severely inhibits translation through its N-terminal region, aa 1 to 107, and this inhibition is antagonized by eEF3. We found that Stm1 stabilizes eEF2 on the 80 S ribosome in the GTP-bound form, independently of eEF2's diphthamide modification, a conserved post-translational modification at the tip of domain IV. Systematic analyses of N- or C-terminal truncated mutants revealed that the core region of Stm1, aa 47 to 143, is crucial for its ribosome binding and eEF2 stabilization. Stm1 does not inhibit the 80 S-dependent GTPase activity of eEF2, at least during the first round of GTP-hydrolysis. The mechanism and the role of the stable association of eEF2 with the ribosome in the presence of Stm1 are discussed in relation to the translation repression by Stm1.
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Affiliation(s)
- Hikari Hayashi
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Riku Nagai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Taisho Abe
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Miki Wada
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Nono Takeuchi-Tomita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
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Zinoviev A, Hellen CUT, Pestova TV. Multiple mechanisms of reinitiation on bicistronic calicivirus mRNAs. Mol Cell 2016; 57:1059-1073. [PMID: 25794616 DOI: 10.1016/j.molcel.2015.01.039] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 12/31/2014] [Accepted: 01/26/2015] [Indexed: 02/05/2023]
Abstract
Reinitiation is a strategy used by viruses to express several cistrons from one mRNA. Although extremely weak after translation of long open reading frames (ORFs) on cellular mRNAs, reinitiation occurs efficiently on subgenomic bicistronic calicivirus mRNAs, enabling synthesis of minor capsid proteins. The process is governed by a short element upstream of the restart AUG, designated "termination upstream ribosomal binding site" (TURBS). It contains the conserved Motif 1 complementary to h26 of 18S rRNA, displayed in the loop of a hairpin formed by species-specific Motifs 2/2(∗). To determine the advantages conferred on reinitiation by TURBS, we reconstituted this process in vitro on two model bicistronic calicivirus mRNAs. We found that post-termination ribosomal tethering of mRNA by TURBS allows reinitiation by post-termination 80S ribosomes and diminishes dependence on eukaryotic initiation factor 3 (eIF3) of reinitiation by recycled 40S subunits, which can be mediated either by eIFs 2/1/1A or by Ligatin following ABCE1-dependent or -independent splitting of post-termination complexes.
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Affiliation(s)
- Alexandra Zinoviev
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
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van den Elzen AMG, Schuller A, Green R, Séraphin B. Dom34-Hbs1 mediated dissociation of inactive 80S ribosomes promotes restart of translation after stress. EMBO J 2014; 33:265-76. [PMID: 24424461 DOI: 10.1002/embj.201386123] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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.
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Affiliation(s)
- Antonia M G van den Elzen
- Equipe 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
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Van Dyke N, Baby J, Van Dyke MW. Stm1p, a ribosome-associated protein, is important for protein synthesis in Saccharomyces cerevisiae under nutritional stress conditions. J Mol Biol 2006; 358:1023-31. [PMID: 16580682 DOI: 10.1016/j.jmb.2006.03.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 03/06/2006] [Accepted: 03/09/2006] [Indexed: 12/22/2022]
Abstract
Stm1p is a Saccharomyces cerevisiae protein that has been implicated in several biological processes, ranging from apoptosis to telomere biosynthesis. Likewise, Stm1p has been identified as a protein associated with supramolecular structures, including ribosomes and nuclear telomere cap complexes. Using a variety of biochemical methods, we found that the vast majority of cellular Stm1p is associated with free cytosolic 80S ribosomes and polysomes. In its association with ribosomes, Stm1p interacts in an equimolar complex with both ribosomal subunits and is not associated with mRNA. Functionally, targeted disruption of the STM1 gene results in rapamycin hypersensitivity and a defect in recovery following nitrogen starvation and replenishment. These effects coincide with severe polysome depletion and reduced total protein synthesis. Taken together, our data indicate that Stm1p plays a critical role in facilitating translation under nutrient stress conditions and suggest that Stm1p acts in concert with the target of rapamycin (TOR) signaling pathway.
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Affiliation(s)
- Natalya Van Dyke
- Department of Molecular and Cellular Oncology, Unit 079, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA
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Current awareness on yeast. Yeast 2005; 22:745-52. [PMID: 16106592 DOI: 10.1002/yea.1165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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