1
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McLaren M, Conners R, Isupov MN, Gil-Díez P, Gambelli L, Gold VAM, Walter A, Connell SR, Williams B, Daum B. CryoEM reveals that ribosomes in microsporidian spores are locked in a dimeric hibernating state. Nat Microbiol 2023; 8:1834-1845. [PMID: 37709902 PMCID: PMC10522483 DOI: 10.1038/s41564-023-01469-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/11/2023] [Indexed: 09/16/2023]
Abstract
Translational control is an essential process for the cell to adapt to varying physiological or environmental conditions. To survive adverse conditions such as low nutrient levels, translation can be shut down almost entirely by inhibiting ribosomal function. Here we investigated eukaryotic hibernating ribosomes from the microsporidian parasite Spraguea lophii in situ by a combination of electron cryo-tomography and single-particle electron cryo-microscopy. We show that microsporidian spores contain hibernating ribosomes that are locked in a dimeric (100S) state, which is formed by a unique dimerization mechanism involving the beak region. The ribosomes within the dimer are fully assembled, suggesting that they are ready to be activated once the host cell is invaded. This study provides structural evidence for dimerization acting as a mechanism for ribosomal hibernation in microsporidia, and therefore demonstrates that eukaryotes utilize this mechanism in translational control.
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Affiliation(s)
- Mathew McLaren
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Rebecca Conners
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Michail N Isupov
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Patricia Gil-Díez
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
- Crop Science Centre, Cambridge University, Cambridge, UK
| | - Lavinia Gambelli
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Vicki A M Gold
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Andreas Walter
- Center of Optical Technologies, Aalen University, Aalen, Germany
| | - Sean R Connell
- Structural Biology of Cellular Machines, IIS Biobizkaia, Barakaldo, Spain
| | - Bryony Williams
- Living Systems Institute, University of Exeter, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Bertram Daum
- Living Systems Institute, University of Exeter, Exeter, UK.
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK.
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2
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Fernández-García L, Muthami JM, Tomas M, Wood TK. What are the options for treating infections by persister-forming pathogens? Environ Microbiol 2022; 24:4500-4504. [PMID: 35912818 DOI: 10.1111/1462-2920.16117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Laura Fernández-García
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA.,Microbiology Translational and Multidisciplinary (MicroTM)-Research Institute Biomedical A Coruña (INIBIC) and Microbiology Department of Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Joy M Muthami
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Maria Tomas
- Microbiology Translational and Multidisciplinary (MicroTM)-Research Institute Biomedical A Coruña (INIBIC) and Microbiology Department of Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
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3
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Jiang W, Wagner J, Du W, Plitzko J, Baumeister W, Beck F, Guo Q. A transformation clustering algorithm and its application in polyribosomes structural profiling. Nucleic Acids Res 2022; 50:9001-9011. [PMID: 35811088 PMCID: PMC9458451 DOI: 10.1093/nar/gkac547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/01/2022] [Accepted: 06/10/2022] [Indexed: 12/26/2022] Open
Abstract
Improvements in cryo-electron tomography sample preparation, electron-microscopy instrumentations, and image processing algorithms have advanced the structural analysis of macromolecules in situ. Beyond such analyses of individual macromolecules, the study of their interactions with functionally related neighbors in crowded cellular habitats, i.e. ‘molecular sociology’, is of fundamental importance in biology. Here we present a NEighboring Molecule TOpology Clustering (NEMO-TOC) algorithm. We optimized this algorithm for the detection and profiling of polyribosomes, which play both constitutive and regulatory roles in gene expression. Our results suggest a model where polysomes are formed by connecting multiple nonstochastic blocks, in which translation is likely synchronized.
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Affiliation(s)
- Wenhong Jiang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University , Beijing 100871, China
| | - Jonathan Wagner
- Department of Structural Molecular Biology, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Wenjing Du
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University , Beijing 100871, China
| | - Juergen Plitzko
- CryoEM Technology, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Structural Molecular Biology, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Florian Beck
- CryoEM Technology, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Qiang Guo
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University , Beijing 100871, China
- Changping Laboratory , Beijing, China
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4
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Vahlensieck C, Thiel CS, Pöschl D, Bradley T, Krammer S, Lauber B, Polzer J, Ullrich O. Post-Transcriptional Dynamics is Involved in Rapid Adaptation to Hypergravity in Jurkat T Cells. Front Cell Dev Biol 2022; 10:933984. [PMID: 35859900 PMCID: PMC9289288 DOI: 10.3389/fcell.2022.933984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 06/10/2022] [Indexed: 12/12/2022] Open
Abstract
The transcriptome of human immune cells rapidly reacts to altered gravity in a highly dynamic way. We could show in previous experiments that transcriptional patterns show profound adaption after seconds to minutes of altered gravity. To gain further insight into these transcriptional alteration and adaption dynamics, we conducted a highly standardized RNA-Seq experiment with human Jurkat T cells exposed to 9xg hypergravity for 3 and 15 min, respectively. We investigated the frequency with which individual exons were used during transcription and discovered that differential exon usage broadly appeared after 3 min and became less pronounced after 15 min. Additionally, we observed a shift in the transcript pool from coding towards non-coding transcripts. Thus, adaption of gravity-sensitive differentially expressed genes followed a dynamic transcriptional rebound effect. The general dynamics were compatible with previous studies on the transcriptional effects of short hypergravity on human immune cells and suggest that initial up-regulatory changes mostly result from increased elongation rates. The shift correlated with a general downregulation of the affected genes. All chromosome bands carried homogenous numbers of gravity-sensitive genes but showed a specific tendency towards up- or downregulation. Altered gravity affected transcriptional regulation throughout the entire genome, whereby the direction of differential expression was strongly dependent on the structural location in the genome. A correlation analysis with potential mediators of the early transcriptional response identified a link between initially upregulated genes with certain transcription factors. Based on these findings, we have been able to further develop our model of the transcriptional response to altered gravity.
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Affiliation(s)
- Christian Vahlensieck
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Innovation Cluster Space and Aviation (UZH Space Hub), Air Force Center, University of Zurich, Dübendorf, Switzerland
| | - Cora S. Thiel
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Innovation Cluster Space and Aviation (UZH Space Hub), Air Force Center, University of Zurich, Dübendorf, Switzerland
- Space Life Sciences Laboratory (SLSL), Kennedy Space Center (KSC), Merritt Island, FL, United States
- Space Biotechnology, Department of Machine Design, Engineering Design and Product Development, Institute of Mechanical Engineering, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- *Correspondence: Cora S. Thiel, ; Oliver Ullrich,
| | - Daniel Pöschl
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Timothy Bradley
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Sonja Krammer
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Innovation Cluster Space and Aviation (UZH Space Hub), Air Force Center, University of Zurich, Dübendorf, Switzerland
| | - Beatrice Lauber
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Jennifer Polzer
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Oliver Ullrich
- Institute of Anatomy, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Innovation Cluster Space and Aviation (UZH Space Hub), Air Force Center, University of Zurich, Dübendorf, Switzerland
- Space Life Sciences Laboratory (SLSL), Kennedy Space Center (KSC), Merritt Island, FL, United States
- Space Biotechnology, Department of Machine Design, Engineering Design and Product Development, Institute of Mechanical Engineering, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Space Medicine, Ernst-Abbe-Hochschule (EAH) Jena, Department of Industrial Engineering, Jena, Germany
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- *Correspondence: Cora S. Thiel, ; Oliver Ullrich,
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5
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Yaeshima C, Murata N, Ishino S, Sagawa I, Ito K, Uchiumi T. A novel ribosome-dimerization protein found in the hyperthermophilic archaeon Pyrococcus furiosus using ribosome-associated proteomics. Biochem Biophys Res Commun 2022; 593:116-121. [DOI: 10.1016/j.bbrc.2022.01.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022]
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6
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Misal SA, Zhao B, Reilly JP. Interpretation of Anomalously Long Crosslinks in Ribosome Crosslinking reveals the ribosome interaction in stationary phase E. coli. RSC Chem Biol 2022; 3:886-894. [PMID: 35866168 PMCID: PMC9257603 DOI: 10.1039/d2cb00101b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/15/2022] [Indexed: 11/21/2022] Open
Abstract
Crosslinking mass spectrometry (XL-MS) of bacterial ribosomes revealed the dynamic intra and intermolecular interactions within the ribosome structure. It has been also extended to capture the interactions of ribosome binding...
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Affiliation(s)
- Santosh A Misal
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
| | - Bingqing Zhao
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
| | - James P Reilly
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
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7
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Li Y, Sharma MR, Koripella RK, Banavali NK, Agrawal RK, Ojha AK. Ribosome hibernation: a new molecular framework for targeting nonreplicating persisters of mycobacteria. MICROBIOLOGY-SGM 2021; 167. [PMID: 33555244 DOI: 10.1099/mic.0.001035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Treatment of tuberculosis requires a multi-drug regimen administered for at least 6 months. The long-term chemotherapy is attributed in part to a minor subpopulation of nonreplicating Mycobacterium tuberculosis cells that exhibit phenotypic tolerance to antibiotics. The origins of these cells in infected hosts remain unclear. Here we discuss some recent evidence supporting the hypothesis that hibernation of ribosomes in M. tuberculosis, induced by zinc starvation, could be one of the primary mechanisms driving the development of nonreplicating persisters in hosts. We further analyse inconsistencies in previously reported studies to clarify the molecular principles underlying mycobacterial ribosome hibernation.
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Affiliation(s)
- Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Nilesh K Banavali
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA.,Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
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8
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Keysberg C, Hertel O, Schelletter L, Busche T, Sochart C, Kalinowski J, Hoffrogge R, Otte K, Noll T. Exploring the molecular content of CHO exosomes during bioprocessing. Appl Microbiol Biotechnol 2021; 105:3673-3689. [PMID: 33937930 PMCID: PMC8102462 DOI: 10.1007/s00253-021-11309-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/25/2021] [Accepted: 03/15/2021] [Indexed: 01/21/2023]
Abstract
Abstract In biopharmaceutical production, Chinese hamster ovary (CHO) cells derived from Cricetulus griseus remain the most commonly used host cell for recombinant protein production, especially antibodies. Over the last decade, in-depth multi-omics characterization of these CHO cells provided data for extensive cell line engineering and corresponding increases in productivity. However, exosomes, extracellular vesicles containing proteins and nucleic acids, are barely researched at all in CHO cells. Exosomes have been proven to be a ubiquitous mediator of intercellular communication and are proposed as new biopharmaceutical format for drug delivery, indicator reflecting host cell condition and anti-apoptotic factor in spent media. Here we provide a brief overview of different separation techniques and subsequently perform a proteome and regulatory, non-coding RNA analysis of exosomes, derived from lab-scale bioreactor cultivations of a CHO-K1 cell line, to lay out reference data for further research in the field. Applying bottom-up orbitrap shotgun proteomics and next-generation small RNA sequencing, we detected 1395 proteins, 144 micro RNA (miRNA), and 914 PIWI-interacting RNA (piRNA) species differentially across the phases of a batch cultivation process. The exosomal proteome and RNA data are compared with other extracellular fractions and cell lysate, yielding several significantly exosome-enriched species. Graphical Abstract ![]()
Key points • First-time comprehensive protein and miRNA characterization of CHO exosomes. • Isolation protocol and time point of bioprocess strongly affect quality of extracellular vesicles. • CHO-derived exosomes also contain numerous piRNA species of yet unknown function. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11309-8.
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Affiliation(s)
- Christoph Keysberg
- Bielefeld University, Bielefeld, Germany. .,University of Applied Sciences Biberach, Biberach, Germany.
| | - Oliver Hertel
- Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Louise Schelletter
- Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Tobias Busche
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | | | - Jörn Kalinowski
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Raimund Hoffrogge
- Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Kerstin Otte
- University of Applied Sciences Biberach, Biberach, Germany
| | - Thomas Noll
- Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
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9
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Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation. Sci Rep 2021; 11:2410. [PMID: 33510206 PMCID: PMC7844247 DOI: 10.1038/s41598-021-81610-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 01/06/2021] [Indexed: 12/11/2022] Open
Abstract
Arabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10 °C, reil mutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while controlling the balance of non-translating 40S- and 60S-subunits. Reil mutations respond by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis may buffer fluctuating translation by pre-existing non-translating ribosomes before de novo synthesis meets temperature-induced demands. Reil1 reil2 double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and alter paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement of de novo synthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control of NUC2 and eIF3C2 transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation.
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10
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Han NC, Kelly P, Ibba M. Translational quality control and reprogramming during stress adaptation. Exp Cell Res 2020; 394:112161. [PMID: 32619498 DOI: 10.1016/j.yexcr.2020.112161] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/18/2022]
Abstract
Organisms encounter stress throughout their lives, and therefore require the ability to respond rapidly to environmental changes. Although transcriptional responses are crucial for controlling changes in gene expression, regulation at the translational level often allows for a faster response at the protein levels which permits immediate adaptation. The fidelity and robustness of protein synthesis are actively regulated under stress. For example, mistranslation can be beneficial to cells upon environmental changes and also alters cellular stress responses. Additionally, stress modulates both global and selective translational regulation through mechanisms including the change of aminoacyl-tRNA activity, tRNA pool reprogramming and ribosome heterogeneity. In this review, we draw on studies from both the prokaryotic and eukaryotic systems to discuss current findings of cellular adaptation at the level of translation, specifically translational fidelity and activity changes in response to a wide array of environmental stressors including oxidative stress, nutrient depletion, temperature variation, antibiotics and host colonization.
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Affiliation(s)
- Nien-Ching Han
- Department of Microbiology, The Ohio State University, Columbus, OH, 43220, USA
| | - Paul Kelly
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH, 43220, USA
| | - Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, OH, 43220, USA.
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11
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Jungers CF, Elliff JM, Masson-Meyers DS, Phiel CJ, Origanti S. Regulation of eukaryotic translation initiation factor 6 dynamics through multisite phosphorylation by GSK3. J Biol Chem 2020; 295:12796-12813. [PMID: 32703900 DOI: 10.1074/jbc.ra120.013324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/16/2020] [Indexed: 01/25/2023] Open
Abstract
Eukaryotic translation initiation factor 6 (eIF6) is essential for the synthesis of 60S ribosomal subunits and for regulating the association of 60S and 40S subunits. A mechanistic understanding of how eIF6 modulates translation in response to stress, specifically starvation-induced stress, is lacking. We here show a novel mode of eIF6 regulation by glycogen synthase kinase 3 (GSK3) that is predominantly active in response to serum starvation. Both GSK3α and GSK3β phosphorylate human eIF6. Multiple residues in the C terminus of eIF6 are phosphorylated by GSK3 in a sequential manner. In response to serum starvation, eIF6 accumulates in the cytoplasm, and this altered localization depends on phosphorylation by GSK3. Disruption of eIF6 phosphorylation exacerbates the translation inhibitory response to serum starvation and stalls cell growth. These results suggest that eIF6 regulation by GSK3 contributes to the attenuation of global protein synthesis that is critical for adaptation to starvation-induced stress.
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Affiliation(s)
- Courtney F Jungers
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA
| | - Jonah M Elliff
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA
| | | | - Christopher J Phiel
- Department of Integrative Biology, University of Colorado Denver, Colorado, USA
| | - Sofia Origanti
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA .,Department of Biology, Saint Louis University, St. Louis, Missouri, USA
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12
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Wells JN, Buschauer R, Mackens-Kiani T, Best K, Kratzat H, Berninghausen O, Becker T, Gilbert W, Cheng J, Beckmann R. Structure and function of yeast Lso2 and human CCDC124 bound to hibernating ribosomes. PLoS Biol 2020; 18:e3000780. [PMID: 32687489 PMCID: PMC7392345 DOI: 10.1371/journal.pbio.3000780] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/30/2020] [Accepted: 07/01/2020] [Indexed: 12/20/2022] Open
Abstract
Cells adjust to nutrient deprivation by reversible translational shutdown. This is accompanied by maintaining inactive ribosomes in a hibernation state, in which they are bound by proteins with inhibitory and protective functions. In eukaryotes, such a function was attributed to suppressor of target of Myb protein 1 (Stm1; SERPINE1 mRNA-binding protein 1 [SERBP1] in mammals), and recently, late-annotated short open reading frame 2 (Lso2; coiled-coil domain containing short open reading frame 124 [CCDC124] in mammals) was found to be involved in translational recovery after starvation from stationary phase. Here, we present cryo-electron microscopy (cryo-EM) structures of translationally inactive yeast and human ribosomes. We found Lso2/CCDC124 accumulating on idle ribosomes in the nonrotated state, in contrast to Stm1/SERBP1-bound ribosomes, which display a rotated state. Lso2/CCDC124 bridges the decoding sites of the small with the GTPase activating center (GAC) of the large subunit. This position allows accommodation of the duplication of multilocus region 34 protein (Dom34)-dependent ribosome recycling system, which splits Lso2-containing, but not Stm1-containing, ribosomes. We propose a model in which Lso2 facilitates rapid translation reactivation by stabilizing the recycling-competent state of inactive ribosomes.
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Affiliation(s)
- Jennifer N. Wells
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Robert Buschauer
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Timur Mackens-Kiani
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Katharina Best
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Hanna Kratzat
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Otto Berninghausen
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Thomas Becker
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Wendy Gilbert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jingdong Cheng
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Roland Beckmann
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
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13
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Ribosome Dimerization Protects the Small Subunit. J Bacteriol 2020; 202:JB.00009-20. [PMID: 32123037 PMCID: PMC7186458 DOI: 10.1128/jb.00009-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/25/2020] [Indexed: 01/21/2023] Open
Abstract
When nutrients become scarce, bacteria can enter an extended state of quiescence. A major challenge of this state is how to preserve ribosomes for the return to favorable conditions. Here, we show that the ribosome dimerization protein hibernation-promoting factor (HPF) functions to protect essential ribosomal proteins. Ribosomes isolated from strains lacking HPF (Δhpf) or encoding a mutant allele of HPF that binds the ribosome but does not mediate dimerization were substantially depleted of the small subunit proteins S2 and S3. Strikingly, these proteins are located directly at the ribosome dimer interface. We used single-particle cryo-electron microscopy (cryo-EM) to further characterize these ribosomes and observed that a high percentage of ribosomes were missing S2, S3, or both. These data support a model in which the ribosome dimerization activity of HPF evolved to protect labile proteins that are essential for ribosome function. HPF is almost universally conserved in bacteria, and HPF deletions in diverse species exhibit decreased viability during starvation. Our data provide mechanistic insight into this phenotype and establish a mechanism for how HPF protects ribosomes during quiescence.IMPORTANCE The formation of ribosome dimers during periods of dormancy is widespread among bacteria. Dimerization is typically mediated by a single protein, hibernation-promoting factor (HPF). Bacteria lacking HPF exhibit strong defects in viability and pathogenesis and, in some species, extreme loss of rRNA. The mechanistic basis of these phenotypes has not been determined. Here, we report that HPF from the Gram-positive bacterium Bacillus subtilis preserves ribosomes by preventing the loss of essential ribosomal proteins at the dimer interface. This protection may explain phenotypes associated with the loss of HPF, since ribosome protection would aid survival during nutrient limitation and impart a strong selective advantage when the bacterial cell rapidly reinitiates growth in the presence of sufficient nutrients.
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14
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Trösch R, Willmund F. The conserved theme of ribosome hibernation: from bacteria to chloroplasts of plants. Biol Chem 2020; 400:879-893. [PMID: 30653464 DOI: 10.1515/hsz-2018-0436] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/03/2019] [Indexed: 12/21/2022]
Abstract
Cells are highly adaptive systems that respond and adapt to changing environmental conditions such as temperature fluctuations or altered nutrient availability. Such acclimation processes involve reprogramming of the cellular gene expression profile, tuning of protein synthesis, remodeling of metabolic pathways and morphological changes of the cell shape. Nutrient starvation can lead to limited energy supply and consequently, remodeling of protein synthesis is one of the key steps of regulation since the translation of the genetic code into functional polypeptides may consume up to 40% of a cell's energy during proliferation. In eukaryotic cells, downregulation of protein synthesis during stress is mainly mediated by modification of the translation initiation factors. Prokaryotic cells suppress protein synthesis by the active formation of dimeric so-called 'hibernating' 100S ribosome complexes. Such a transition involves a number of proteins which are found in various forms in prokaryotes but also in chloroplasts of plants. Here, we review the current understanding of these hibernation factors and elaborate conserved principles which are shared between species.
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Affiliation(s)
- Raphael Trösch
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
| | - Felix Willmund
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
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15
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Boye E, Grallert B. eIF2α phosphorylation and the regulation of translation. Curr Genet 2019; 66:293-297. [PMID: 31485739 DOI: 10.1007/s00294-019-01026-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/27/2022]
Abstract
We discuss novel insight into the role and consequences of the phosphorylation of the translation initiation factor eIF2α in the context of stress responses and cell-cycle regulation. eIF2α is centrally located to regulate translation and its phosphorylation in response to different environmental challenges is one of the best characterized stress-response pathways. In addition to its role in stress management, eIF2α phosphorylation is also linked to cell-cycle progression and memory consolidation in the nervous system. The best known consequences of eIF2α phosphorylation are downregulation of global translation and stimulation of translation of some mRNAs. However, recent evidence shows that (i) eIF2α phosphorylation is not always required for the downregulation of global translation after exposure to stress and (ii) eIF2α phosphorylation does not necessarily lead to the downregulation of global translation. These results suggest that the textbook view of eIF2α phosphorylation needs to be revised and that there must be additional regulatory mechanisms at play.
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Affiliation(s)
- Erik Boye
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Beáta Grallert
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
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16
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Matzov D, Bashan A, Yap MNF, Yonath A. Stress response as implemented by hibernating ribosomes: a structural overview. FEBS J 2019; 286:3558-3565. [PMID: 31230411 PMCID: PMC6746590 DOI: 10.1111/febs.14968] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/14/2019] [Accepted: 06/20/2019] [Indexed: 02/07/2023]
Abstract
Protein synthesis is one of the most energy demanding cellular processes. The ability to regulate protein synthesis is essential for cells under normal as well as stress conditions, such as nutrient deficiencies. One mechanism for protein synthesis suppression is the dimerization of ribosomes into hibernation complexes. In most cells, this process is promoted by the hibernating promoting factor (HPF) and in a small group of Gram-negative bacteria (γ-proteobacteria), the dimer formation is induced by a shorter version of HPF (HPFshort ) and by an additional protein, the ribosome modulation factor. In most bacteria, the product of this process is the 100S ribosome complex. Recent advances in cryogenic electron microscopy methods resulted in an abundance of detailed structures of near atomic resolutions 100S complexes that allow for a better understanding of the dimerization process and the way it inhibits protein synthesis. As ribosomal dimerization is vital for cell survival, this process is an attractive target for the development of novel antimicrobial substances that might inhibit or stabilize the complex formation. As different dimerization processes exist among bacteria, including pathogens, this process may provide the basis for species-specific design of antimicrobial agents. Here, we review in detail the various dimerization mechanisms and discuss how they affect the overall dimer structures of the bacterial ribosomes.
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Affiliation(s)
- Donna Matzov
- Structural Biology, Weizmann Institute. Rehovot, Israel
| | - Anat Bashan
- Structural Biology, Weizmann Institute. Rehovot, Israel
| | - Mee-Ngan F Yap
- Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA.,Microbiology and Immunology, Northwestern University, Chicago, IL, USA
| | - Ada Yonath
- Structural Biology, Weizmann Institute. Rehovot, Israel
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17
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Abstract
Protein synthesis consumes a large fraction of available resources in the cell. When bacteria encounter unfavorable conditions and cease to grow, specialized mechanisms are in place to ensure the overall reduction of costly protein synthesis while maintaining a basal level of translation. A number of ribosome-associated factors are involved in this regulation; some confer an inactive, hibernating state of the ribosome in the form of 70S monomers (RaiA; this and the following are based on Escherichia coli nomenclature) or 100S dimers (RMF and HPF homologs), and others inhibit translation at different stages in the translation cycle (RsfS, YqjD and paralogs, SRA, and EttA). Stationary phase cells therefore exhibit a complex array of different ribosome subpopulations that adjusts the translational capacity of the cell to the encountered conditions and ensures efficient reactivation of translation when conditions improve. Here, we review the current state of research regarding stationary phase-specific translation factors, in particular ribosome hibernation factors and other forms of translational regulation in response to stress conditions.
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Affiliation(s)
- Thomas Prossliner
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark;
| | | | | | - Kenn Gerdes
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark;
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18
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O’Connell AE, Gerashchenko MV, O’Donohue MF, Rosen SM, Huntzinger E, Gleeson D, Galli A, Ryder E, Cao S, Murphy Q, Kazerounian S, Morton SU, Schmitz-Abe K, Gladyshev VN, Gleizes PE, Séraphin B, Agrawal PB. Mammalian Hbs1L deficiency causes congenital anomalies and developmental delay associated with Pelota depletion and 80S monosome accumulation. PLoS Genet 2019; 15:e1007917. [PMID: 30707697 PMCID: PMC6373978 DOI: 10.1371/journal.pgen.1007917] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 02/13/2019] [Accepted: 12/25/2018] [Indexed: 12/18/2022] Open
Abstract
Hbs1 has been established as a central component of the cell's translational quality control pathways in both yeast and prokaryotic models; however, the functional characteristics of its human ortholog (Hbs1L) have not been well-defined. We recently reported a novel human phenotype resulting from a mutation in the critical coding region of the HBS1L gene characterized by facial dysmorphism, severe growth restriction, axial hypotonia, global developmental delay and retinal pigmentary deposits. Here we further characterize downstream effects of the human HBS1L mutation. HBS1L has three transcripts in humans, and RT-PCR demonstrated reduced mRNA levels corresponding with transcripts V1 and V2 whereas V3 expression was unchanged. Western blot analyses revealed Hbs1L protein was absent in the patient cells. Additionally, polysome profiling revealed an abnormal aggregation of 80S monosomes in patient cells under baseline conditions. RNA and ribosomal sequencing demonstrated an increased translation efficiency of ribosomal RNA in Hbs1L-deficient fibroblasts, suggesting that there may be a compensatory increase in ribosome translation to accommodate the increased 80S monosome levels. This enhanced translation was accompanied by upregulation of mTOR and 4-EBP protein expression, suggesting an mTOR-dependent phenomenon. Furthermore, lack of Hbs1L caused depletion of Pelota protein in both patient cells and mouse tissues, while PELO mRNA levels were unaffected. Inhibition of proteasomal function partially restored Pelota expression in human Hbs1L-deficient cells. We also describe a mouse model harboring a knockdown mutation in the murine Hbs1l gene that shared several of the phenotypic elements observed in the Hbs1L-deficient human including facial dysmorphism, growth restriction and retinal deposits. The Hbs1lKO mice similarly demonstrate diminished Pelota levels that were rescued by proteasome inhibition.
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Affiliation(s)
- Amy E. O’Connell
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Maxim V. Gerashchenko
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marie-Francoise O’Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Samantha M. Rosen
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Eric Huntzinger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Université de Strasbourg, Centre National de La Recherche Scientifique UMR 7104, INSERM U964, Strasbourg, France
| | - Diane Gleeson
- Wellcome Sanger Institute, Cambridge, United Kingdom
| | | | - Edward Ryder
- Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Siqi Cao
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Quinn Murphy
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Shideh Kazerounian
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Sarah U. Morton
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Klaus Schmitz-Abe
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Vadim N. Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Bertrand Séraphin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Université de Strasbourg, Centre National de La Recherche Scientifique UMR 7104, INSERM U964, Strasbourg, France
| | - Pankaj B. Agrawal
- Division of Newborn Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
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19
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The Structural and Functional Organization of Ribosomal Compartment in the Cell: A Mystery or a Reality? Trends Biochem Sci 2018; 43:938-950. [PMID: 30337135 DOI: 10.1016/j.tibs.2018.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/21/2018] [Accepted: 09/21/2018] [Indexed: 11/23/2022]
Abstract
Great progress has been made toward solving the atomic structure of the ribosome, which is the main biosynthetic machine in cells, but we still do not have a full picture of exactly how cellular ribosomes function. Based on the analysis of crystallographic and electron microscopy data, we propose a basic model of the structural organization of ribosomes into a compartment. This compartment is regularly formed by arrays of ribosomal tetramers made up of two dimers that are actually facing in opposite directions. The compartment functions as the main 'factory' for the production of cellular proteins. The model is consistent with the existing biochemical and genetic data. We also consider the functional connections of such a compartment with cellular transcription and ribosomal biogenesis.
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20
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Ho YH, Shishkova E, Hose J, Coon JJ, Gasch AP. Decoupling Yeast Cell Division and Stress Defense Implicates mRNA Repression in Translational Reallocation during Stress. Curr Biol 2018; 28:2673-2680.e4. [PMID: 30078561 DOI: 10.1016/j.cub.2018.06.044] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/24/2018] [Accepted: 06/19/2018] [Indexed: 12/29/2022]
Abstract
Stress tolerance and rapid growth are often competing interests in cells. Upon severe environmental stress, many organisms activate defense systems concurrent with growth arrest. There has been debate as to whether aspects of the stress-activated transcriptome are regulated by stress or an indirect byproduct of reduced proliferation. For example, stressed Saccharomyces cerevisiae cells mount a common gene expression program called the environmental stress response (ESR) [1] comprised of ∼300 induced (iESR) transcripts involved in stress defense and ∼600 reduced (rESR) mRNAs encoding ribosomal proteins (RPs) and ribosome biogenesis factors (RiBi) important for division. Because ESR activation also correlates with reduced growth rate in nutrient-restricted chemostats and prolonged G1 in slow-growing mutants, an alternate proposal is that the ESR is simply a consequence of reduced division [2-5]. A major challenge is that past studies did not separate effects of division arrest and stress defense; thus, the true responsiveness of the ESR-and the purpose of stress-dependent rESR repression in particular-remains unclear. Here, we decoupled cell division from the stress response by following transcriptome, proteome, and polysome changes in arrested cells responding to acute stress. We show that the ESR cannot be explained by changes in growth rate or cell-cycle phase during stress acclimation. Instead, failure to repress rESR transcripts reduces polysome association of induced transcripts, delaying production of their proteins. Our results suggest that stressed cells alleviate competition for translation factors by removing mRNAs and ribosomes from the translating pool, directing translational capacity toward induced transcripts to accelerate protein production.
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Affiliation(s)
- Yi-Hsuan Ho
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Evgenia Shishkova
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - James Hose
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Joshua J Coon
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Morgridge Institute for Research, Madison, WI 53715, USA
| | - Audrey P Gasch
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA.
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21
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Survival of the drowsiest: the hibernating 100S ribosome in bacterial stress management. Curr Genet 2017; 64:753-760. [PMID: 29243175 PMCID: PMC6060826 DOI: 10.1007/s00294-017-0796-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/09/2017] [Accepted: 12/11/2017] [Indexed: 11/24/2022]
Abstract
In response to nutrient deprivation and environmental insults, bacteria conjoin two copies of non-translating 70S ribosomes that form the translationally inactive 100S dimer. This widespread phenomenon is believed to prevent ribosome turnover and serves as a reservoir that, when conditions become favorable, allows the hibernating ribosomes to be disassembled and recycled for translation. New structural studies have revealed two distinct mechanisms for dimerizing 70S ribosomes, but the molecular basis of the disassembly process is still in its infancy. Many details regarding the sequence of dimerization-dissociation events with respect to the binding and departure of the hibernation factor and its antagonizing disassembly factor remain unclear.
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22
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Opitz N, Schmitt K, Hofer-Pretz V, Neumann B, Krebber H, Braus GH, Valerius O. Capturing the Asc1p/ Receptor for Activated C Kinase 1 (RACK1) Microenvironment at the Head Region of the 40S Ribosome with Quantitative BioID in Yeast. Mol Cell Proteomics 2017; 16:2199-2218. [PMID: 28982715 DOI: 10.1074/mcp.m116.066654] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 09/29/2017] [Indexed: 12/13/2022] Open
Abstract
The Asc1 protein of Saccharomyces cerevisiae is a scaffold protein at the head region of ribosomal 40S that links mRNA translation to cellular signaling. In this study, proteins that colocalize with Asc1p were identified with proximity-dependent Biotin IDentification (BioID), an in vivo labeling technique described here for the first time for yeast. Biotinylated Asc1p-birA*-proximal proteins were identified and quantitatively verified against controls applying SILAC and mass spectrometry. The mRNA-binding proteins Sro9p and Gis2p appeared together with Scp160p, each providing ribosomes with nuclear transcripts. The cap-binding protein eIF4E (Cdc33p) and the eIF3/a-subunit (Rpg1p) were identified reflecting the encounter of proteins involved in the initiation of mRNA translation at the head region of ribosomal 40S. Unexpectedly, a protein involved in ribosome preservation (the clamping factor Stm1p), the deubiquitylation complex Ubp3p-Bre5p, the RNA polymerase II degradation factor 1 (Def1p), and transcription factors (Spt5p, Mbf1p) colocalize with Asc1p in exponentially growing cells. For Asc1R38D, K40Ep, a variant considered to be deficient in binding to ribosomes, BioID revealed its predominant ribosome localization. Glucose depletion replaced most of the Asc1p colocalizing proteins for additional ribosomal proteins, suggesting a ribosome aggregation process during early nutrient limitation, possibly concomitant with ribosomal subunit clamping. Overall, the characterization of the Asc1p microenvironment with BioID confirmed and substantiated our recent findings that the β-propeller broadly contributes to signal transduction influencing phosphorylation of colocalizing proteins (e.g. of Bre5p), and by that might affect nuclear gene transcription and the fate of ribosomes.
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Affiliation(s)
- Nadine Opitz
- From the ‡Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Kerstin Schmitt
- From the ‡Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Verena Hofer-Pretz
- From the ‡Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Bettina Neumann
- §Department of Molecular Genetics, Institute of Microbiology and Genetics, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Heike Krebber
- §Department of Molecular Genetics, Institute of Microbiology and Genetics, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Gerhard H Braus
- From the ‡Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Oliver Valerius
- From the ‡Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany;
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23
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A general mechanism of ribosome dimerization revealed by single-particle cryo-electron microscopy. Nat Commun 2017; 8:722. [PMID: 28959045 PMCID: PMC5620043 DOI: 10.1038/s41467-017-00718-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 07/20/2017] [Indexed: 12/15/2022] Open
Abstract
Bacteria downregulate their ribosomal activity through dimerization of 70S ribosomes, yielding inactive 100S complexes. In Escherichia coli, dimerization is mediated by the hibernation promotion factor (HPF) and ribosome modulation factor. Here we report the cryo-electron microscopy study on 100S ribosomes from Lactococcus lactis and a dimerization mechanism involving a single protein: HPFlong. The N-terminal domain of HPFlong binds at the same site as HPF in Escherichia coli 100S ribosomes. Contrary to ribosome modulation factor, the C-terminal domain of HPFlong binds exactly at the dimer interface. Furthermore, ribosomes from Lactococcus lactis do not undergo conformational changes in the 30S head domains upon binding of HPFlong, and the Shine–Dalgarno sequence and mRNA entrance tunnel remain accessible. Ribosome activity is blocked by HPFlong due to the inhibition of mRNA recognition by the platform binding center. Phylogenetic analysis of HPF proteins suggests that HPFlong-mediated dimerization is a widespread mechanism of ribosome hibernation in bacteria. When bacteria enter the stationary growth phase, protein translation is suppressed via the dimerization of 70S ribosomes into inactive complexes. Here the authors provide a structural basis for how the dual domain hibernation promotion factor promotes ribosome dimerization and hibernation in bacteria.
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24
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Curran JA, Weiss B. What Is the Impact of mRNA 5' TL Heterogeneity on Translational Start Site Selection and the Mammalian Cellular Phenotype? Front Genet 2016; 7:156. [PMID: 27630668 PMCID: PMC5005323 DOI: 10.3389/fgene.2016.00156] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/16/2016] [Indexed: 12/23/2022] Open
Abstract
A major determinant in the efficiency of ribosome loading onto mRNAs is the 5′ TL (transcript leader or 5′ UTR). In addition, elements within this region also impact on start site selection demonstrating that it can modulate the protein readout at both quantitative and qualitative levels. With the increasing wealth of data generated by the mining of the mammalian transcriptome, it has become evident that a genes 5′ TL is not homogeneous but actually exhibits significant heterogeneity. This arises due to the utilization of alternative promoters, and is further compounded by significant variability with regards to the precise transcriptional start sites of each (not to mention alternative splicing). Consequently, the transcript for a protein coding gene is not a unique mRNA, but in-fact a complexed quasi-species of variants whose composition may respond to the changing physiological environment of the cell. Here we examine the potential impact of these events with regards to the protein readout.
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Affiliation(s)
- Joseph A Curran
- Department of Microbiology and Molecular Medicine, Medical School, University of GenevaGeneva, Switzerland; Institute of Genetics and Genomics of Geneva, University of GenevaGeneva, Switzerland
| | - Benjamin Weiss
- Department of Microbiology and Molecular Medicine, Medical School, University of Geneva Geneva, Switzerland
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25
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Ma C, Yan K, Tan D, Li N, Zhang Y, Yuan Y, Li Z, Dong MQ, Lei J, Gao N. Structural dynamics of the yeast Shwachman-Diamond syndrome protein (Sdo1) on the ribosome and its implication in the 60S subunit maturation. Protein Cell 2016; 7:187-200. [PMID: 26850260 PMCID: PMC4791427 DOI: 10.1007/s13238-015-0242-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 12/14/2015] [Indexed: 12/16/2022] Open
Abstract
The human Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease caused by mutations in a highly conserved ribosome assembly factor SBDS. The functional role of SBDS is to cooperate with another assembly factor, elongation factor 1-like (Efl1), to promote the release of eukaryotic initiation factor 6 (eIF6) from the late-stage cytoplasmic 60S precursors. In the present work, we characterized, both biochemically and structurally, the interaction between the 60S subunit and SBDS protein (Sdo1p) from yeast. Our data show that Sdo1p interacts tightly with the mature 60S subunit in vitro through its domain I and II, and is capable of bridging two 60S subunits to form a stable 2:2 dimer. Structural analysis indicates that Sdo1p bind to the ribosomal P-site, in the proximity of uL16 and uL5, and with direct contact to H69 and H38. The dynamic nature of Sdo1p on the 60S subunit, together with its strategic binding position, suggests a surveillance role of Sdo1p in monitoring the conformational maturation of the ribosomal P-site. Altogether, our data support a conformational signal-relay cascade during late-stage 60S maturation, involving uL16, Sdo1p, and Efl1p, which interrogates the functional P-site to control the departure of the anti-association factor eIF6.
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Affiliation(s)
- Chengying Ma
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Kaige Yan
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Dan Tan
- National Institute of Biological Sciences, Beijing, 102206, China.,Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Ningning Li
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yixiao Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yi Yuan
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhifei Li
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, 102206, China.,Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Jianlin Lei
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ning Gao
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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26
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Nomura T, Ito M, Kanamori M, Shigeno Y, Uchiumi T, Arai R, Tsukada M, Hirabayashi K, Ohkawa K. Characterization of silk gland ribosomes from a bivoltine caddisfly, Stenopsyche marmorata: translational suppression of a silk protein in cold conditions. Biochem Biophys Res Commun 2015; 469:210-5. [PMID: 26646291 DOI: 10.1016/j.bbrc.2015.11.112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
Abstract
Larval Stenopsyche marmorata constructs food capture nets and fixed retreats underwater using self-produced proteinaceous silk fibers. In the Chikuma River (Nagano Prefecture, Japan) S. marmorata has a bivoltine life cycle; overwintering larvae grow slowly with reduced net spinning activity in winter. We recently reported constant transcript abundance of S. marmorata silk protein 1 (Smsp-1), a core S. marmorata silk fiber component, in all seasons, implying translational suppression in the silk gland during winter. Herein, we prepared and characterized silk gland ribosomes from seasonally collected S. marmorata larvae. Ribosomes from silk glands immediately frozen in liquid nitrogen (LN2) after dissection exhibited comparable translation elongation activity in spring, summer, and autumn. Conversely, silk glands obtained in winter did not contain active ribosomes and Smsp-1. Ribosomes from silk glands immersed in ice-cold physiological saline solution for approximately 4 h were translationally inactive, despite summer collection and Smsp-1 expression. The ribosomal inactivation occurs because of defects in the formation of 80S ribosomes, presumably due to splitting of 60S subunits containing 28S rRNA with central hidden break, in response to cold stress. These results suggest a novel-type ribosome-regulated translation control mechanism.
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Affiliation(s)
- Takaomi Nomura
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan.
| | - Miho Ito
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan
| | - Mai Kanamori
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan
| | - Yuta Shigeno
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan
| | - Toshio Uchiumi
- Department of Biology, Faculty of Science, Niigata University, Niigata 950-2181, Japan
| | - Ryoichi Arai
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto 390-8621, Japan
| | - Masuhiro Tsukada
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan
| | - Kimio Hirabayashi
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan; Institute of Mountain Science, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Minamiminowa, Nagano 399-4598, Japan
| | - Kousaku Ohkawa
- Institute for Fiber Engineering, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Ueda 386-8567, Japan
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27
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Krokowski D, Jobava R, Guan BJ, Farabaugh K, Wu J, Majumder M, Bianchi MG, Snider MD, Bussolati O, Hatzoglou M. Coordinated Regulation of the Neutral Amino Acid Transporter SNAT2 and the Protein Phosphatase Subunit GADD34 Promotes Adaptation to Increased Extracellular Osmolarity. J Biol Chem 2015; 290:17822-17837. [PMID: 26041779 DOI: 10.1074/jbc.m114.636217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Indexed: 02/04/2023] Open
Abstract
Cells respond to shrinkage induced by increased extracellular osmolarity via programmed changes in gene transcription and mRNA translation. The immediate response to this stress includes the induction of expression of the neutral amino acid transporter SNAT2. Increased SNAT2-mediated uptake of neutral amino acids is an essential adaptive mechanism for restoring cell volume. In contrast, stress-induced phosphorylation of the α subunit of the translation initiation factor eIF2 (eIF2α) can promote apoptosis. Here we show that the response to mild hyperosmotic stress involves regulation of the phosphorylation of eIF2α by increased levels of GADD34, a regulatory subunit of protein phosphatase 1 (PP1). The induction of GADD34 was dependent on transcriptional control by the c-Jun-binding cAMP response element in the GADD34 gene promoter and posttranscriptional stabilization of its mRNA. This mechanism differs from the regulation of GADD34 expression by other stresses that involve activating transcription factor 4 (ATF4). ATF4 was not translated during hyperosmotic stress despite an increase in eIF2α phosphorylation. The SNAT2-mediated increase in amino acid uptake was enhanced by increased GADD34 levels in a manner involving decreased eIF2α phosphorylation. It is proposed that the induction of the SNAT2/GADD34 axis enhances cell survival by promoting the immediate adaptive response to stress.
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Affiliation(s)
- Dawid Krokowski
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
| | - Raul Jobava
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Bo-Jhih Guan
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Kenneth Farabaugh
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Jing Wu
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Mithu Majumder
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Massimiliano G Bianchi
- Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, 43100 Parma, Italy
| | - Martin D Snider
- Departments of Biochemistry, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Ovidio Bussolati
- Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, 43100 Parma, Italy
| | - Maria Hatzoglou
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
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28
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Goel A, Eckhardt TH, Puri P, de Jong A, Branco Dos Santos F, Giera M, Fusetti F, de Vos WM, Kok J, Poolman B, Molenaar D, Kuipers OP, Teusink B. Protein costs do not explain evolution of metabolic strategies and regulation of ribosomal content: does protein investment explain an anaerobic bacterial Crabtree effect? Mol Microbiol 2015; 97:77-92. [PMID: 25828364 DOI: 10.1111/mmi.13012] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2015] [Indexed: 01/21/2023]
Abstract
Protein investment costs are considered a major driver for the choice of alternative metabolic strategies. We tested this premise in Lactococcus lactis, a bacterium that exhibits a distinct, anaerobic version of the bacterial Crabtree/Warburg effect; with increasing growth rates it shifts from a high yield metabolic mode [mixed-acid fermentation; 3 adenosine triphosphate (ATP) per glucose] to a low yield metabolic mode (homolactic fermentation; 2 ATP per glucose). We studied growth rate-dependent relative transcription and protein ratios, enzyme activities, and fluxes of L. lactis in glucose-limited chemostats, providing a high-quality and comprehensive data set. A three- to fourfold higher growth rate rerouted metabolism from acetate to lactate as the main fermentation product. However, we observed hardly any changes in transcription, protein levels and enzyme activities. Even levels of ribosomal proteins, constituting a major investment in cellular machinery, changed only slightly. Thus, contrary to the original hypothesis, central metabolism in this organism appears to be hardly regulated at the level of gene expression, but rather at the metabolic level. We conclude that L. lactis is either poorly adapted to growth at low and constant glucose concentrations, or that protein costs play a less important role in fitness than hitherto assumed.
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Affiliation(s)
- Anisha Goel
- Systems Bioinformatics IBIVU, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.,Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands.,Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands
| | - Thomas H Eckhardt
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Pranav Puri
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Anne de Jong
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Filipe Branco Dos Santos
- Systems Bioinformatics IBIVU, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.,Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands
| | - Martin Giera
- Systems Bioinformatics IBIVU, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Fabrizia Fusetti
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Willem M de Vos
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands
| | - Jan Kok
- Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands.,Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Bert Poolman
- Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands.,Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Douwe Molenaar
- Systems Bioinformatics IBIVU, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.,Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands
| | - Oscar P Kuipers
- Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands.,Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Netherlands Proteomics Centre and Zernike Institute for Advanced Materials (ZIAM), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Bas Teusink
- Systems Bioinformatics IBIVU, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.,Kluyver Centre for Genomics of Industrial Fermentation/Netherlands consortium for Systems Biology (NCSB), P.O. Box 5057, 2600 GA, Delft, The Netherlands
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29
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Development, antibiotic production, and ribosome assembly in Streptomyces venezuelae are impacted by RNase J and RNase III deletion. J Bacteriol 2014; 196:4253-67. [PMID: 25266378 DOI: 10.1128/jb.02205-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA metabolism is a critical but frequently overlooked control element affecting virtually every cellular process in bacteria. RNA processing and degradation is mediated by a suite of ribonucleases having distinct cleavage and substrate specificity. Here, we probe the role of two ribonucleases (RNase III and RNase J) in the emerging model system Streptomyces venezuelae. We show that each enzyme makes a unique contribution to the growth and development of S. venezuelae and further affects the secondary metabolism and antibiotic production of this bacterium. We demonstrate a connection between the action of these ribonucleases and translation, with both enzymes being required for the formation of functional ribosomes. RNase III mutants in particular fail to properly process 23S rRNA, form fewer 70S ribosomes, and show reduced translational processivity. The loss of either RNase III or RNase J additionally led to the appearance of a new ribosomal species (the 100S ribosome dimer) during exponential growth and dramatically sensitized these mutants to a range of antibiotics.
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30
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Yoshida H, Wada A. The 100S ribosome: ribosomal hibernation induced by stress. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:723-32. [PMID: 24944100 DOI: 10.1002/wrna.1242] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/18/2014] [Accepted: 04/18/2014] [Indexed: 01/01/2023]
Abstract
One of the most important cellular events in all organisms is protein synthesis (translation), which is catalyzed by ribosomes. The regulation of translational activity is dependent on the environmental situation of the cell. A decrease in overall translation under stress conditions is mainly accompanied by the formation of functionally inactive 100S ribosomes in bacteria. The 100S ribosome is a dimer of two 70S ribosomes that is formed through interactions between their 30S subunits. Two mechanisms of 100S ribosome formation are known: one involving ribosome modulation factor (RMF) and short hibernation promoting factor (HPF) in a part of Gammaproteobacteria including Escherichia coli, and the other involving only long HPF in the majority of bacteria. The expression of RMF is regulated by ppGpp and cyclic AMP-cAMP receptor protein (cAMP-CRP) induced by amino acid starvation and glucose depletion, respectively. When stress conditions are removed, the 100S ribosome immediately dissociates into the active 70S ribosomes by releasing RMF. The stage in the ribosome cycle at which the ribosome loses translational activity is referred to as 'Hibernation'. The lifetime of cells that cannot form 100S ribosomes by deletion of the rmf gene is shorter than that of parental cells under stress conditions in E. coli. This fact indicates that the interconversion system between active 70S ribosomes and inactive 100S ribosomes is an important survival strategy for bacteria.
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Affiliation(s)
- Hideji Yoshida
- Department of Physics, Osaka Medical College, Osaka, Japan
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31
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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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32
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Ueta M, Wada C, Daifuku T, Sako Y, Bessho Y, Kitamura A, Ohniwa RL, Morikawa K, Yoshida H, Kato T, Miyata T, Namba K, Wada A. Conservation of two distinct types of 100S ribosome in bacteria. Genes Cells 2013; 18:554-74. [PMID: 23663662 DOI: 10.1111/gtc.12057] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 03/19/2013] [Indexed: 11/29/2022]
Abstract
In bacteria, 70S ribosomes (consisting of 30S and 50S subunits) dimerize to form 100S ribosomes, which were first discovered in Escherichia coli. Ribosome modulation factor (RMF) and hibernation promoting factor (HPF) mediate this dimerization in stationary phase. The 100S ribosome is translationally inactive, but it dissociates into two translationally active 70S ribosomes after transfer from starvation to fresh medium. Therefore, the 100S ribosome is called the 'hibernating ribosome'. The gene encoding RMF is found widely throughout the Gammaproteobacteria class, but is not present in any other bacteria. In this study, 100S ribosome formation in six species of Gammaproteobacteria and eight species belonging to other bacterial classes was compared. There were several marked differences between the two groups: (i) Formation of 100S ribosomes was mediated by RMF and short HPF in Gammaproteobacteria species, similar to E. coli, whereas it was mediated only by long HPF in the other bacterial species; (ii) RMF/short HPF-mediated 100S ribosome formation occurred specifically in stationary phase, whereas long HPF-mediated 100S ribosome formation occurred in all growth phases; and (iii) 100S ribosomes formed by long HPF were much more stable than those formed by RMF and short HPF.
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Affiliation(s)
- Masami Ueta
- Yoshida Biological Laboratory, Yamashina, Kyoto 607-8081, Japan
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33
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Saikia M, Krokowski D, Guan BJ, Ivanov P, Parisien M, Hu GF, Anderson P, Pan T, Hatzoglou M. Genome-wide identification and quantitative analysis of cleaved tRNA fragments induced by cellular stress. J Biol Chem 2012; 287:42708-25. [PMID: 23086926 DOI: 10.1074/jbc.m112.371799] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Certain stress conditions can induce cleavage of tRNAs around the anticodon loop via the use of the ribonuclease angiogenin. The cellular factors that regulate tRNA cleavage are not well known. In this study we used normal and eIF2α phosphorylation-deficient mouse embryonic fibroblasts and applied a microarray-based methodology to identify and compare tRNA cleavage patterns in response to hypertonic stress, oxidative stress (arsenite), and treatment with recombinant angiogenin. In all three scenarios mouse embryonic fibroblasts deficient in eIF2α phosphorylation showed a higher accumulation of tRNA fragments including those derived from initiator-tRNA(Met). We have shown that tRNA cleavage is regulated by the availability of angiogenin, its substrate (tRNA), the levels of the angiogenin inhibitor RNH1, and the rates of protein synthesis. These conclusions are supported by the following findings: (i) exogenous treatment with angiogenin or knockdown of RNH1 increased tRNA cleavage; (ii) tRNA fragment accumulation was higher during oxidative stress than hypertonic stress, in agreement with a dramatic decrease of RNH1 levels during oxidative stress; and (iii) a positive correlation was observed between angiogenin-mediated tRNA cleavage and global protein synthesis rates. Identification of the stress-specific tRNA cleavage mechanisms and patterns will provide insights into the role of tRNA fragments in signaling pathways and stress-related disorders.
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Affiliation(s)
- Mridusmita Saikia
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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