1
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Sinha NK, McKenney C, Yeow ZY, Li JJ, Nam KH, Yaron-Barir TM, Johnson JL, Huntsman EM, Cantley LC, Ordureau A, Regot S, Green R. The ribotoxic stress response drives UV-mediated cell death. Cell 2024; 187:3652-3670.e40. [PMID: 38843833 PMCID: PMC11246228 DOI: 10.1016/j.cell.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 03/03/2024] [Accepted: 05/09/2024] [Indexed: 06/13/2024]
Abstract
While ultraviolet (UV) radiation damages DNA, eliciting the DNA damage response (DDR), it also damages RNA, triggering transcriptome-wide ribosomal collisions and eliciting a ribotoxic stress response (RSR). However, the relative contributions, timing, and regulation of these pathways in determining cell fate is unclear. Here we use time-resolved phosphoproteomic, chemical-genetic, single-cell imaging, and biochemical approaches to create a chronological atlas of signaling events activated in cells responding to UV damage. We discover that UV-induced apoptosis is mediated by the RSR kinase ZAK and not through the DDR. We identify two negative-feedback modules that regulate ZAK-mediated apoptosis: (1) GCN2 activation limits ribosomal collisions and attenuates ZAK-mediated RSR and (2) ZAK activity leads to phosphodegron autophosphorylation and its subsequent degradation. These events tune ZAK's activity to collision levels to establish regimes of homeostasis, tolerance, and death, revealing its key role as the cellular sentinel for nucleic acid damage.
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Affiliation(s)
- Niladri K Sinha
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Connor McKenney
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhong Y Yeow
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jeffrey J Li
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ki Hong Nam
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Tomer M Yaron-Barir
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Englander Institute for Precision Medicine, Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY 10021, USA; Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Jared L Johnson
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Emily M Huntsman
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Alban Ordureau
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Sergi Regot
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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2
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Wei G, Russo S, Tuorto F. Lost in translation: How neurons cope with tRNA decoding. Bioessays 2024:e2400107. [PMID: 38990077 DOI: 10.1002/bies.202400107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024]
Abstract
Post-transcriptional tRNA modifications contribute to the decoding efficiency of tRNAs by supporting codon recognition and tRNA stability. Recent work shows that the molecular and cellular functions of tRNA modifications and tRNA-modifying-enzymes are linked to brain development and neurological disorders. Lack of these modifications affects codon recognition and decoding rate, promoting protein aggregation and translational stress response pathways with toxic consequences to the cell. In this review, we discuss the peculiarity of local translation in neurons, suggesting a role for fine-tuning of translation performed by tRNA modifications. We provide several examples of tRNA modifications involved in physiology and pathology of the nervous system, highlighting their effects on protein translation and discussing underlying mechanisms, like the unfolded protein response (UPR), ribosome quality control (RQC), and no-go mRNA decay (NGD), which could affect neuronal functions. We aim to deepen the understanding of the roles of tRNA modifications and the coordination of these modifications with the protein translation machinery in the nervous system.
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Affiliation(s)
- Guo Wei
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Stefano Russo
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Francesca Tuorto
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
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3
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Gibbs VJ, Lin YH, Ghuge AA, Anderson RA, Schiemann AH, Conaglen L, Sansom BJM, da Silva RC, Sattlegger E. GCN2 in Viral Defence and the Subversive Tactics Employed by Viruses. J Mol Biol 2024; 436:168594. [PMID: 38724002 DOI: 10.1016/j.jmb.2024.168594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/01/2024] [Accepted: 05/01/2024] [Indexed: 06/10/2024]
Abstract
The recent SARS-CoV-2 pandemic and associated COVID19 disease illustrates the important role of viral defence mechanisms in ensuring survival and recovery of the host or patient. Viruses absolutely depend on the host's protein synthesis machinery to replicate, meaning that impeding translation is a powerful way to counteract viruses. One major approach used by cells to obstruct protein synthesis is to phosphorylate the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α). Mammals possess four different eIF2α-kinases: PKR, HRI, PEK/PERK, and GCN2. While PKR is currently considered the principal eIF2α-kinase involved in viral defence, the other eIF2α-kinases have also been found to play significant roles. Unsurprisingly, viruses have developed mechanisms to counteract the actions of eIF2α-kinases, or even to exploit them to their benefit. While some of these virulence factors are specific to one eIF2α-kinase, such as GCN2, others target all eIF2α-kinases. This review critically evaluates the current knowledge of viral mechanisms targeting the eIF2α-kinase GCN2. A detailed and in-depth understanding of the molecular mechanisms by which viruses evade host defence mechanisms will help to inform the development of powerful anti-viral measures.
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Affiliation(s)
- Victoria J Gibbs
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Yu H Lin
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Aditi A Ghuge
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Reuben A Anderson
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Anja H Schiemann
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Layla Conaglen
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Bianca J M Sansom
- School of Natural Sciences, Massey University, Auckland, New Zealand
| | - Richard C da Silva
- School of Natural Sciences, Massey University, Auckland, New Zealand; Genome Biology and Epigenetics, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Evelyn Sattlegger
- School of Food Technology and Natural Sciences, Massey University, Palmerston North, New Zealand; School of Natural Sciences, Massey University, Auckland, New Zealand; Maurice Wilkins Centre for Molecular BioDiscovery, Palmerston North, New Zealand.
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4
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Karasik A, Lorenzi HA, DePass AV, Guydosh NR. Endonucleolytic RNA cleavage drives changes in gene expression during the innate immune response. Cell Rep 2024; 43:114287. [PMID: 38823018 PMCID: PMC11251458 DOI: 10.1016/j.celrep.2024.114287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 04/05/2024] [Accepted: 05/13/2024] [Indexed: 06/03/2024] Open
Abstract
Viral infection triggers several double-stranded RNA (dsRNA) sensors that lead to changes in gene expression in the cell. One of these sensors activates an endonuclease, ribonuclease L (RNase L), that cleaves single-stranded RNA. However, how the resultant widespread RNA fragmentation affects gene expression is not fully understood. Here, we show that this fragmentation induces the ribotoxic stress response via ZAKα, potentially through stalled ribosomes and/or ribosome collisions. The p38 and JNK pathways that are activated as part of this response promote outcomes that inhibit the virus, such as programmed cell death. We also show that RNase L limits the translation of stress-responsive genes. Intriguingly, we found that the activity of the generic endonuclease, RNase A, recapitulates many of the same molecular phenotypes as activated RNase L, demonstrating how widespread RNA cleavage can evoke an antiviral program.
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Affiliation(s)
- Agnes Karasik
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hernan A Lorenzi
- TriLab Bioinformatics Group, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew V DePass
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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5
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Yin JZ, Keszei AFA, Houliston S, Filandr F, Beenstock J, Daou S, Kitaygorodsky J, Schriemer DC, Mazhab-Jafari MT, Gingras AC, Sicheri F. The HisRS-like domain of GCN2 is a pseudoenzyme that can bind uncharged tRNA. Structure 2024; 32:795-811.e6. [PMID: 38531363 DOI: 10.1016/j.str.2024.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 01/09/2024] [Accepted: 02/28/2024] [Indexed: 03/28/2024]
Abstract
GCN2 is a stress response kinase that phosphorylates the translation initiation factor eIF2α to inhibit general protein synthesis when activated by uncharged tRNA and stalled ribosomes. The presence of a HisRS-like domain in GCN2, normally associated with tRNA aminoacylation, led to the hypothesis that eIF2α kinase activity is regulated by the direct binding of this domain to uncharged tRNA. Here we solved the structure of the HisRS-like domain in the context of full-length GCN2 by cryoEM. Structure and function analysis shows the HisRS-like domain of GCN2 has lost histidine and ATP binding but retains tRNA binding abilities. Hydrogen deuterium exchange mass spectrometry, site-directed mutagenesis and computational docking experiments support a tRNA binding model that is partially shifted from that employed by bona fide HisRS enzymes. These results demonstrate that the HisRS-like domain of GCN2 is a pseudoenzyme and advance our understanding of GCN2 regulation and function.
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Affiliation(s)
- Jay Z Yin
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Alexander F A Keszei
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Scott Houliston
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada; Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Frantisek Filandr
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jonah Beenstock
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada
| | - Salima Daou
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada
| | - Julia Kitaygorodsky
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Mohammad T Mazhab-Jafari
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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6
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Aviner R, Lee TT, Masto VB, Li KH, Andino R, Frydman J. Polyglutamine-mediated ribotoxicity disrupts proteostasis and stress responses in Huntington's disease. Nat Cell Biol 2024; 26:892-902. [PMID: 38741019 DOI: 10.1038/s41556-024-01414-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/01/2024] [Indexed: 05/16/2024]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the Huntingtin (HTT) gene, encoding a homopolymeric polyglutamine (polyQ) tract. Although mutant HTT (mHTT) protein is known to aggregate, the links between aggregation and neurotoxicity remain unclear. Here we show that both translation and aggregation of wild-type HTT and mHTT are regulated by a stress-responsive upstream open reading frame and that polyQ expansions cause abortive translation termination and release of truncated, aggregation-prone mHTT fragments. Notably, we find that mHTT depletes translation elongation factor eIF5A in brains of symptomatic HD mice and cultured HD cells, leading to pervasive ribosome pausing and collisions. Loss of eIF5A disrupts homeostatic controls and impairs recovery from acute stress. Importantly, drugs that inhibit translation initiation reduce premature termination and mitigate this escalating cascade of ribotoxic stress and dysfunction in HD.
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Affiliation(s)
- Ranen Aviner
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub San Francisco, San Francisco, CA, USA
| | - Ting-Ting Lee
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Vincent B Masto
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Kathy H Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Judith Frydman
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA.
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7
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Zheng X, Shen J, Jiang H, Tian M, Wang Q, Guo K, Chen R, Xia Q, Yan Q, Du L, Duan S. Exploring the multifaceted role of GCN1: Implications in cellular responses and disease pathogenesis. Biomed Pharmacother 2024; 175:116681. [PMID: 38705128 DOI: 10.1016/j.biopha.2024.116681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/21/2024] [Accepted: 04/29/2024] [Indexed: 05/07/2024] Open
Abstract
GCN1 is a highly conserved protein present widely across eukaryotes. As an upstream activator of protein kinase GCN2, GCN1 plays a pivotal role in integrated stress responses, such as amino acid starvation and oxidative stress. Through interaction with GCN2, GCN1 facilitates the activation of GCN2, thus initiating downstream signaling cascades in response to cellular stressors. In these contexts, the activation of GCN2 necessitates the presence and action of GCN1. Notably, GCN1 also operates as a ribosome collision sensor, contributing significantly to the translation quality control pathway. These discoveries offer valuable insights into cellular responses to internal stresses, vital for maintaining cellular homeostasis. Additionally, GCN1 exhibits the ability to regulate the cell cycle and suppress inflammation, among other processes, independently of GCN2. Our review outlines the structural characteristics and biological functions of GCN1, shedding light on its significant involvement in the onset and progression of various cancer and non-cancer diseases. Our work underscores the role of GCN1 in the context of drug therapeutic effects, hinting at its potential as a promising drug target. Furthermore, our work delves deep into the functional mechanisms of GCN1, promising innovative avenues for the diagnosis and treatment of diseases in the future. The exploration of GCN1's multifaceted roles not only enhances our understanding of its mechanisms but also paves the way for novel therapeutic interventions. The ongoing quest to unveil additional functions of GCN1 holds the promise of further enriching our comprehension of its mode of action.
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Affiliation(s)
- Xinying Zheng
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Jinze Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Hongting Jiang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Mei Tian
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China; Geriatric Medicine Center, Department of Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, China
| | - Qurui Wang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Kailin Guo
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Ruixiu Chen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Qing Xia
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Qibin Yan
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Lihua Du
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Shiwei Duan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China.
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8
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Turnbull K, Paternoga H, von der Weth E, Egorov AA, Pochopien AA, Zhang Y, Nersisyan L, Margus T, Johansson MJ, Pelechano V, Wilson DN, Hauryliuk V. The ABCF ATPase New1 resolves translation termination defects associated with specific tRNA Arg and tRNA Lys isoacceptors in the P site. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596377. [PMID: 38854126 PMCID: PMC11160720 DOI: 10.1101/2024.05.29.596377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The efficiency of translation termination is determined by the nature of the stop codon as well as its context. In eukaryotes, recognition of the A-site stop codon and release of the polypeptide are mediated by release factors eRF1 and eRF3, respectively. Translation termination is modulated by other factors which either directly interact with release factors or bind to the E-site and modulate the activity of the peptidyl transferase center. Previous studies suggested that the Saccharomyces cerevisiae ABCF ATPase New1 is involved in translation termination and/or ribosome recycling, however, the exact function remained unclear. Here, we have applied 5PSeq, single-particle cryo-EM and readthrough reporter assays to provide insight into the biological function of New1. We show that the lack of New1 results in ribosomal stalling at stop codons preceded by a lysine or arginine codon and that the stalling is not defined by the nature of the C-terminal amino acid but rather by the identity of the tRNA isoacceptor in the P-site. Collectively, our results suggest that translation termination is inefficient when ribosomes have specific tRNA isoacceptors in the P-site and that the recruitment of New1 rescues ribosomes at these problematic termination contexts.
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Affiliation(s)
- Kathryn Turnbull
- Department of Clinical Microbiology, Rigshospitalet, 2200 Copenhagen, Denmark
| | - Helge Paternoga
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Esther von der Weth
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Artyom A. Egorov
- Department of Experimental Medicine, University of Lund, 221 84 Lund, Sweden
| | - Agnieszka A Pochopien
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Yujie Zhang
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna, Sweden
| | - Lilit Nersisyan
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna, Sweden
- Armenian Bioinformatics Institute, Yerevan, Armenia
- Institute of Molecular Biology, National Academy of Sciences of Armenia, Yerevan, Armenia
| | | | | | - Vicent Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna, Sweden
| | - Daniel N. Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Vasili Hauryliuk
- Department of Experimental Medicine, University of Lund, 221 84 Lund, Sweden
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
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9
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Emanuelli G, Zhu J, Li W, Morrell NW, Marciniak SJ. Functional validation of EIF2AK4 (GCN2) missense variants associated with pulmonary arterial hypertension. Hum Mol Genet 2024:ddae082. [PMID: 38776952 DOI: 10.1093/hmg/ddae082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Pulmonary arterial hypertension (PAH) is a disorder with a large genetic component. Biallelic mutations of EIF2AK4, which encodes the kinase GCN2, are causal in two ultra-rare subtypes of PAH, pulmonary veno-occlusive disease and pulmonary capillary haemangiomatosis. EIF2AK4 variants of unknown significance have also been identified in patients with classical PAH, though their relationship to disease remains unclear. To provide patients with diagnostic information and enable family testing, the functional consequences of such rare variants must be determined, but existing computational methods are imperfect. We applied a suite of bioinformatic and experimental approaches to sixteen EIF2AK4 variants that had been identified in patients. By experimentally testing the functional integrity of the integrated stress response (ISR) downstream of GCN2, we determined that existing computational tools have insufficient sensitivity to reliably predict impaired kinase function. We determined experimentally that several EIF2AK4 variants identified in patients with classical PAH had preserved function and are therefore likely to be non-pathogenic. The dysfunctional variants of GCN2 that we identified could be subclassified into three groups: misfolded, kinase-dead, and hypomorphic. Intriguingly, members of the hypomorphic group were amenable to paradoxical activation by a type-1½ GCN2 kinase inhibitor. This experiment approach may aid in the clinical stratification of EIF2AK4 variants and potentially identify hypomorophic alleles receptive to pharmacological activation.
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Affiliation(s)
- Giulia Emanuelli
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Keith Peters Building, Biomedical Campus, Hills Rd, Cambridge CB2 0XY, United Kingdom
| | - JiaYi Zhu
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Keith Peters Building, Biomedical Campus, Hills Rd, Cambridge CB2 0XY, United Kingdom
| | - Wei Li
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Papworth Road, Trumpington, Cambridge CB2 0BB, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Box 157), Hills Road, Cambridge CB2 2QQ, United Kingdom
| | - Nicholas W Morrell
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Papworth Road, Trumpington, Cambridge CB2 0BB, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Box 157), Hills Road, Cambridge CB2 2QQ, United Kingdom
- Royal Papworth Hospital NHS Foundation Trust, Papworth Rd, Trumpington, Cambridge CB2 0AY, United Kingdom
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Keith Peters Building, Biomedical Campus, Hills Rd, Cambridge CB2 0XY, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital (Box 157), Hills Road, Cambridge CB2 2QQ, United Kingdom
- Royal Papworth Hospital NHS Foundation Trust, Papworth Rd, Trumpington, Cambridge CB2 0AY, United Kingdom
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10
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Surya A, Bolton BM, Rothe R, Mejia-Trujillo R, Zhao Q, Leonita A, Liu Y, Rangan R, Gorusu Y, Nguyen P, Cenik C, Cenik ES. Cytosolic Ribosomal Protein Haploinsufficiency affects Mitochondrial Morphology and Respiration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589775. [PMID: 38659761 PMCID: PMC11042305 DOI: 10.1101/2024.04.16.589775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The interplay between ribosomal protein composition and mitochondrial function is essential for sustaining energy homeostasis. Precise stoichiometric production of ribosomal proteins is crucial to maximize protein synthesis efficiency while reducing the energy costs to the cell. However, the impact of this balance on mitochondrial ATP generation, morphology and function remains unclear. Particularly, the loss of a single copy ribosomal protein gene is observed in Mendelian disorders like Diamond Blackfan Anemia and is common in somatic tumors, yet the implications of this imbalance on mitochondrial function and energy dynamics are still unclear. In this study, we investigated the impact of haploinsufficiency for four ribosomal protein genes implicated in ribosomopathy disorders (rps-10, rpl-5, rpl-33, rps-23) in Caenorhabditis elegans and corresponding reductions in human lymphoblast cells. Our findings uncover significant, albeit variably penetrant, mitochondrial morphological differences across these mutants, alongside an upregulation of glutathione transferases, and SKN-1 dependent increase in oxidative stress resistance, indicative of increased ROS production. Specifically, loss of a single copy of rps-10 in C. elegans led to decreased mitochondrial activity, characterized by lower energy levels and reduced oxygen consumption. A similar reduction in mitochondrial activity and energy levels was observed in human leukemia cells with a 50% reduction in RPS10 transcript levels. Importantly, we also observed alterations in the translation efficiency of nuclear and mitochondrial electron transport chain components in response to reductions in ribosomal protein genes' expression in both C. elegans and human cells. This suggests a conserved mechanism whereby the synthesis of components vital for mitochondrial function are adjusted in the face of compromised ribosomal machinery. Finally, mitochondrial membrane and cytosolic ribosomal components exhibited significant covariation at the RNA and translation efficiency level in lymphoblastoid cells across a diverse group of individuals, emphasizing the interplay between the protein synthesis machinery and mitochondrial energy production. By uncovering the impact of ribosomal protein haploinsufficiency on the translation efficiency of electron transport chain components, mitochondrial physiology, and the adaptive stress responses, we provide evidence for an evolutionarily conserved strategy to safeguard cellular functionality under genetic stress.
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Affiliation(s)
- Agustian Surya
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Blythe Marie Bolton
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Reed Rothe
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Raquel Mejia-Trujillo
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Qiuxia Zhao
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Amanda Leonita
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Yue Liu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Rekha Rangan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Yasash Gorusu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Pamela Nguyen
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Can Cenik
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Elif Sarinay Cenik
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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11
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Nanjaraj Urs AN, Lasehinde V, Kim L, McDonald E, Yan LL, Zaher HS. Inability to rescue stalled ribosomes results in overactivation of the integrated stress response. J Biol Chem 2024; 300:107290. [PMID: 38636664 PMCID: PMC11106528 DOI: 10.1016/j.jbc.2024.107290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 04/20/2024] Open
Abstract
Endogenous and exogenous chemical agents are known to compromise the integrity of RNA and cause ribosome stalling and collisions. Recent studies have shown that collided ribosomes serve as sensors for multiple processes, including ribosome quality control (RQC) and the integrated stress response (ISR). Since RQC and the ISR have distinct downstream consequences, it is of great importance that organisms activate the appropriate process. We previously showed that RQC is robustly activated in response to collisions and suppresses the ISR activation. However, the molecular mechanics behind this apparent competition were not immediately clear. Here we show that Hel2 does not physically compete with factors of the ISR, but instead its ribosomal-protein ubiquitination activity, and downstream resolution of collided ribosomes, is responsible for suppressing the ISR. Introducing a mutation in the RING domain of Hel2-which inhibits its ubiquitination activity and downstream RQC but imparts higher affinity of the factor for collided ribosomes-resulted in increased activation of the ISR upon MMS-induced alkylation stress. Similarly, mutating Hel2's lysine targets in uS10, which is responsible for RQC activation, resulted in increased Gcn4 target induction. Remarkably, the entire process of RQC appears to be limited by the action of Hel2, as the overexpression of this one factor dramatically suppressed the activation of the ISR. Collectively, our data suggest that cells evolved Hel2 to bind collided ribosomes with a relatively high affinity but kept its concentration relatively low, ensuring that it gets exhausted under stress conditions that cannot be resolved by quality control processes.
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Affiliation(s)
| | - Victor Lasehinde
- Department of Biology, Washington University in St Louis, St Louis, Missouri, USA
| | - Lucas Kim
- Department of Biology, Washington University in St Louis, St Louis, Missouri, USA
| | - Elesa McDonald
- Department of Biology, Washington University in St Louis, St Louis, Missouri, USA
| | - Liewei L Yan
- Department of Biology, Washington University in St Louis, St Louis, Missouri, USA
| | - Hani S Zaher
- Department of Biology, Washington University in St Louis, St Louis, Missouri, USA.
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12
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Shanmugam R, Anderson R, Schiemann AH, Sattlegger E. Evidence that Xrn1 is in complex with Gcn1, and is required for full levels of eIF2α phosphorylation. Biochem J 2024; 481:481-498. [PMID: 38440860 PMCID: PMC11088878 DOI: 10.1042/bcj20220531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/04/2024] [Accepted: 03/05/2024] [Indexed: 03/06/2024]
Abstract
The protein kinase Gcn2 and its effector protein Gcn1 are part of the general amino acid control signalling (GAAC) pathway best known in yeast for its function in maintaining amino acid homeostasis. Under amino acid limitation, Gcn2 becomes activated, subsequently increasing the levels of phosphorylated eIF2α (eIF2α-P). This leads to the increased translation of transcriptional regulators, such as Gcn4 in yeast and ATF4 in mammals, and subsequent re-programming of the cell's gene transcription profile, thereby allowing cells to cope with starvation. Xrn1 is involved in RNA decay, quality control and processing. We found that Xrn1 co-precipitates Gcn1 and Gcn2, suggesting that these three proteins are in the same complex. Growth under starvation conditions was dependent on Xrn1 but not on Xrn1-ribosome association, and this correlated with reduced eIF2α-P levels. Constitutively active Gcn2 leads to a growth defect due to eIF2α-hyperphosphorylation, and we found that this phenotype was independent of Xrn1, suggesting that xrn1 deletion does not enhance eIF2α de-phosphorylation. Our study provides evidence that Xrn1 is required for efficient Gcn2 activation, directly or indirectly. Thus, we have uncovered a potential new link between RNA metabolism and the GAAC.
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Affiliation(s)
- Renuka Shanmugam
- School of Natural Sciences, Massey University, Auckland, New Zealand
| | - Reuben Anderson
- School of Natural Sciences, Massey University, Auckland, New Zealand
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Anja H. Schiemann
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Evelyn Sattlegger
- School of Natural Sciences, Massey University, Auckland, New Zealand
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
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13
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Bharti N, Santos L, Davyt M, Behrmann S, Eichholtz M, Jimenez-Sanchez A, Hong JS, Rab A, Sorscher EJ, Albers S, Ignatova Z. Translation velocity determines the efficacy of engineered suppressor tRNAs on pathogenic nonsense mutations. Nat Commun 2024; 15:2957. [PMID: 38580646 PMCID: PMC10997658 DOI: 10.1038/s41467-024-47258-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 03/20/2024] [Indexed: 04/07/2024] Open
Abstract
Nonsense mutations - the underlying cause of approximately 11% of all genetic diseases - prematurely terminate protein synthesis by mutating a sense codon to a premature stop or termination codon (PTC). An emerging therapeutic strategy to suppress nonsense defects is to engineer sense-codon decoding tRNAs to readthrough and restore translation at PTCs. However, the readthrough efficiency of the engineered suppressor tRNAs (sup-tRNAs) largely varies in a tissue- and sequence context-dependent manner and has not yet yielded optimal clinical efficacy for many nonsense mutations. Here, we systematically analyze the suppression efficacy at various pathogenic nonsense mutations. We discover that the translation velocity of the sequence upstream of PTCs modulates the sup-tRNA readthrough efficacy. The PTCs most refractory to suppression are embedded in a sequence context translated with an abrupt reversal of the translation speed leading to ribosomal collisions. Moreover, modeling translation velocity using Ribo-seq data can accurately predict the suppression efficacy at PTCs. These results reveal previously unknown molecular signatures contributing to genotype-phenotype relationships and treatment-response heterogeneity, and provide the framework for the development of personalized tRNA-based gene therapies.
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Affiliation(s)
- Nikhil Bharti
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany
| | - Leonardo Santos
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany
| | - Marcos Davyt
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany
| | - Stine Behrmann
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany
| | - Marie Eichholtz
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany
| | | | - Jeong S Hong
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
- Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Andras Rab
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
- Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Eric J Sorscher
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
- Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Suki Albers
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany.
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146, Hamburg, Germany.
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14
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Ryoo HD. The integrated stress response in metabolic adaptation. J Biol Chem 2024; 300:107151. [PMID: 38462161 PMCID: PMC10998230 DOI: 10.1016/j.jbc.2024.107151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/28/2024] [Accepted: 03/03/2024] [Indexed: 03/12/2024] Open
Abstract
The integrated stress response (ISR) refers to signaling pathways initiated by stress-activated eIF2α kinases. Distinct eIF2α kinases respond to different stress signals, including amino acid deprivation and mitochondrial stress. Such stress-induced eIF2α phosphorylation attenuates general mRNA translation and, at the same time, stimulates the preferential translation of specific downstream factors to orchestrate an adaptive gene expression program. In recent years, there have been significant new advances in our understanding of ISR during metabolic stress adaptation. Here, I discuss those advances, reviewing among others the ISR activation mechanisms in response to amino acid deprivation and mitochondrial stress. In addition, I review how ISR regulates the amino acid metabolic pathways and how changes in the ISR impact the physiology and pathology of various disease models.
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Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York, USA.
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15
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Fedry J, Silva J, Vanevic M, Fronik S, Mechulam Y, Schmitt E, des Georges A, Faller WJ, Förster F. Visualization of translation reorganization upon persistent ribosome collision stress in mammalian cells. Mol Cell 2024; 84:1078-1089.e4. [PMID: 38340715 PMCID: PMC7615912 DOI: 10.1016/j.molcel.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 11/06/2023] [Accepted: 01/18/2024] [Indexed: 02/12/2024]
Abstract
Aberrantly slow ribosomes incur collisions, a sentinel of stress that triggers quality control, signaling, and translation attenuation. Although each collision response has been studied in isolation, the net consequences of their collective actions in reshaping translation in cells is poorly understood. Here, we apply cryoelectron tomography to visualize the translation machinery in mammalian cells during persistent collision stress. We find that polysomes are compressed, with up to 30% of ribosomes in helical polysomes or collided disomes, some of which are bound to the stress effector GCN1. The native collision interface extends beyond the in vitro-characterized 40S and includes the L1 stalk and eEF2, possibly contributing to translocation inhibition. The accumulation of unresolved tRNA-bound 80S and 60S and aberrant 40S configurations identifies potentially limiting steps in collision responses. Our work provides a global view of the translation machinery in response to persistent collisions and a framework for quantitative analysis of translation dynamics in situ.
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Affiliation(s)
- Juliette Fedry
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands; MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
| | - Joana Silva
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Mihajlo Vanevic
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Stanley Fronik
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Amédée des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, City University of New York, New York, NY, USA; Department of Chemistry and Biochemistry, The City College of New York, New York, NY, USA; Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center, City University of New York, New York, NY, USA
| | - William James Faller
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
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16
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Tatara Y, Kasai S, Kokubu D, Tsujita T, Mimura J, Itoh K. Emerging Role of GCN1 in Disease and Homeostasis. Int J Mol Sci 2024; 25:2998. [PMID: 38474243 PMCID: PMC10931611 DOI: 10.3390/ijms25052998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/29/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
GCN1 is recognized as a factor that is essential for the activation of GCN2, which is a sensor of amino acid starvation. This function is evolutionarily conserved from yeast to higher eukaryotes. However, recent studies have revealed non-canonical functions of GCN1 that are independent of GCN2, such as its participation in cell proliferation, apoptosis, and the immune response, beyond the borders of species. Although it is known that GCN1 and GCN2 interact with ribosomes to accomplish amino acid starvation sensing, recent studies have reported that GCN1 binds to disomes (i.e., ribosomes that collide each other), thereby regulating both the co-translational quality control and stress response. We propose that GCN1 regulates ribosome-mediated signaling by dynamically changing its partners among RWD domain-possessing proteins via unknown mechanisms. We recently demonstrated that GCN1 is essential for cell proliferation and whole-body energy regulation in mice. However, the manner in which ribosome-initiated signaling via GCN1 is related to various physiological functions warrants clarification. GCN1-mediated mechanisms and its interaction with other quality control and stress response signals should be important for proteostasis during aging and neurodegenerative diseases, and may be targeted for drug development.
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Affiliation(s)
- Yota Tatara
- Department of Stress Response Science, Biomedical Research Center, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
| | - Shuya Kasai
- Department of Stress Response Science, Biomedical Research Center, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
| | - Daichi Kokubu
- Diet and Well-Being Research Institute, KAGOME, Co., Ltd., 17 Nishitomiyama, Nasushiobara 329-2762, Tochigi, Japan
- Department of Vegetable Life Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
| | - Tadayuki Tsujita
- Laboratory of Biochemistry, Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, 1 Honjo-machi, Saga City 840-8502, Saga, Japan;
| | - Junsei Mimura
- Department of Stress Response Science, Biomedical Research Center, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
| | - Ken Itoh
- Department of Stress Response Science, Biomedical Research Center, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
- Department of Vegetable Life Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Aomori, Japan
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17
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Zhang H, Ling J. Serine mistranslation induces the integrated stress response without accumulation of uncharged tRNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.04.578812. [PMID: 38370842 PMCID: PMC10871240 DOI: 10.1101/2024.02.04.578812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that support robust and accurate protein synthesis. A rapidly expanding number of studies show that mutations in aaRSs lead to multiple human diseases, including neurological disorders and cancer. Much remains unknown about how aaRS mutations impact human health. In particular, how aminoacylation errors affect stress responses and fitness in eukaryotic cells remains poorly understood. The integrated stress response (ISR) is an adaptive mechanism in response to multiple stresses. However, chronic activation of the ISR contributes to the development of multiple diseases (e.g., neuropathies). Here we show that Ser misincorporation into Ala and Thr codons, resulting from aaRS editing defects or mutations in tRNAs, constitutively active the ISR. Such activation does not appear to depend on the accumulation of uncharged tRNAs, implicating that Ser mistranslation may lead to ribosome stalling and collision.
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Affiliation(s)
- Hong Zhang
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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18
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Lamsal M, Luker HA, Pinch M, Hansen IA. RNAi-Mediated Knockdown of Acidic Ribosomal Stalk Protein P1 Arrests Egg Development in Adult Female Yellow Fever Mosquitoes, Aedes aegypti. INSECTS 2024; 15:84. [PMID: 38392504 PMCID: PMC10889338 DOI: 10.3390/insects15020084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/10/2024] [Accepted: 01/20/2024] [Indexed: 02/24/2024]
Abstract
After taking a blood meal, the fat body of the adult female yellow fever mosquito, Aedes aegypti, switches from a previtellogenic state of arrest to an active state of synthesizing large quantities of yolk protein precursors (YPPs) that are crucial for egg development. The synthesis of YPPs is regulated at both the transcriptional and translational levels. Previously, we identified the cytoplasmic protein general control nonderepressible 1 (GCN1) as a part of the translational regulatory pathway for YPP synthesis. In the current study, we used the C-terminal end of GCN1 to screen for protein-protein interactions and identified 60S acidic ribosomal protein P1 (P1). An expression analysis and RNAi-mediated knockdown of P1 was performed to further investigate the role of P1 in mosquito reproduction. We showed that in unfed (absence of a blood meal) adult A. aegypti mosquitoes, P1 was expressed ubiquitously in the mosquito organs and tissues tested. We also showed that the RNAi-mediated knockdown of P1 in unfed adult female mosquitoes resulted in a strong, transient knockdown with observable phenotypic changes in ovary length and egg deposition. Our results suggest that 60S acidic ribosomal protein P1 is necessary for mosquito reproduction and is a promising target for mosquito population control.
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Affiliation(s)
- Mahesh Lamsal
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Hailey A Luker
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Matthew Pinch
- Department of Biology, University of Texas El Paso, El Paso, TX 79968, USA
| | - Immo A Hansen
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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19
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Duan N, Hand E, Pheko M, Sharma S, Emiola A. Structure-guided discovery of anti-CRISPR and anti-phage defense proteins. Nat Commun 2024; 15:649. [PMID: 38245560 PMCID: PMC10799925 DOI: 10.1038/s41467-024-45068-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/12/2024] [Indexed: 01/22/2024] Open
Abstract
Bacteria use a variety of defense systems to protect themselves from phage infection. In turn, phages have evolved diverse counter-defense measures to overcome host defenses. Here, we use protein structural similarity and gene co-occurrence analyses to screen >66 million viral protein sequences and >330,000 metagenome-assembled genomes for the identification of anti-phage and counter-defense systems. We predict structures for ~300,000 proteins and perform large-scale, pairwise comparison to known anti-CRISPR (Acr) and anti-phage proteins to identify structural homologs that otherwise may not be uncovered using primary sequence search. This way, we identify a Bacteroidota phage Acr protein that inhibits Cas12a, and an Akkermansia muciniphila anti-phage defense protein, termed BxaP. Gene bxaP is found in loci encoding Bacteriophage Exclusion (BREX) and restriction-modification defense systems, but confers immunity independently. Our work highlights the advantage of combining protein structural features and gene co-localization information in studying host-phage interactions.
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Affiliation(s)
- Ning Duan
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Emily Hand
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Mannuku Pheko
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Shikha Sharma
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Akintunde Emiola
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
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20
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Zhao S, Cordes J, Caban KM, Götz MJ, Mackens-Kiani T, Veltri AJ, Sinha NK, Weickert P, Kaya S, Hewitt G, Nedialkova DD, Fröhlich T, Beckmann R, Buskirk AR, Green R, Stingele J. RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks. Mol Cell 2023; 83:4290-4303.e9. [PMID: 37951216 PMCID: PMC10783637 DOI: 10.1016/j.molcel.2023.10.012] [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: 04/13/2023] [Revised: 08/17/2023] [Accepted: 10/13/2023] [Indexed: 11/13/2023]
Abstract
Reactive aldehydes are abundant endogenous metabolites that challenge homeostasis by crosslinking cellular macromolecules. Aldehyde-induced DNA damage requires repair to prevent cancer and premature aging, but it is unknown whether cells also possess mechanisms that resolve aldehyde-induced RNA lesions. Here, we establish photoactivatable ribonucleoside-enhanced crosslinking (PAR-CL) as a model system to study RNA crosslinking damage in the absence of confounding DNA damage in human cells. We find that such RNA damage causes translation stress by stalling elongating ribosomes, which leads to collisions with trailing ribosomes and activation of multiple stress response pathways. Moreover, we discovered a translation-coupled quality control mechanism that resolves covalent RNA-protein crosslinks. Collisions between translating ribosomes and crosslinked mRNA-binding proteins trigger their modification with atypical K6- and K48-linked ubiquitin chains. Ubiquitylation requires the E3 ligase RNF14 and leads to proteasomal degradation of the protein adduct. Our findings identify RNA lesion-induced translational stress as a central component of crosslinking damage.
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Affiliation(s)
- Shubo Zhao
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jacqueline Cordes
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Karolina M Caban
- Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Maximilian J Götz
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Timur Mackens-Kiani
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Anthony J Veltri
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Niladri K Sinha
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Pedro Weickert
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Selay Kaya
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Graeme Hewitt
- King's College London School of Cancer & Pharmaceutical Sciences, London, UK
| | - Danny D Nedialkova
- Max Planck Institute of Biochemistry, Martinsried, Germany; Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Garching, Germany
| | - Thomas Fröhlich
- Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Roland Beckmann
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Allen R Buskirk
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Julian Stingele
- Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany.
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21
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Boone M, Zappa F. Signaling plasticity in the integrated stress response. Front Cell Dev Biol 2023; 11:1271141. [PMID: 38143923 PMCID: PMC10740175 DOI: 10.3389/fcell.2023.1271141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023] Open
Abstract
The Integrated Stress Response (ISR) is an essential homeostatic signaling network that controls the cell's biosynthetic capacity. Four ISR sensor kinases detect multiple stressors and relay this information to downstream effectors by phosphorylating a common node: the alpha subunit of the eukaryotic initiation factor eIF2. As a result, general protein synthesis is repressed while select transcripts are preferentially translated, thus remodeling the proteome and transcriptome. Mounting evidence supports a view of the ISR as a dynamic signaling network with multiple modulators and feedback regulatory features that vary across cell and tissue types. Here, we discuss updated views on ISR sensor kinase mechanisms, how the subcellular localization of ISR components impacts signaling, and highlight ISR signaling differences across cells and tissues. Finally, we consider crosstalk between the ISR and other signaling pathways as a determinant of cell health.
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22
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Ugajin N, Imami K, Takada H, Ishihama Y, Chiba S, Mishima Y. Znf598-mediated Rps10/eS10 ubiquitination contributes to the ribosome ubiquitination dynamics during zebrafish development. RNA (NEW YORK, N.Y.) 2023; 29:1910-1927. [PMID: 37751929 PMCID: PMC10653392 DOI: 10.1261/rna.079633.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023]
Abstract
The ribosome is a translational apparatus that comprises about 80 ribosomal proteins and four rRNAs. Recent studies reported that ribosome ubiquitination is crucial for translational regulation and ribosome-associated quality control (RQC). However, little is known about the dynamics of ribosome ubiquitination under complex biological processes of multicellular organisms. To explore ribosome ubiquitination during animal development, we generated a zebrafish strain that expresses a FLAG-tagged ribosomal protein Rpl36/eL36 from its endogenous locus. We examined ribosome ubiquitination during zebrafish development by combining affinity purification of ribosomes from rpl36-FLAG zebrafish embryos with immunoblotting analysis. Our findings showed that the ubiquitination of ribosomal proteins dynamically changed as development proceeded. We also showed that during zebrafish development, the ribosome was ubiquitinated by Znf598, an E3 ubiquitin ligase that activates RQC. Ribosomal protein Rps10/eS10 was found to be a key ubiquitinated protein during development. Furthermore, we showed that Rps10/eS10 ubiquitination-site mutations reduced the overall ubiquitination pattern of the ribosome. These results demonstrate the complexity and dynamics of ribosome ubiquitination during zebrafish development.
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Affiliation(s)
- Nozomi Ugajin
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555, Japan
| | - Koshi Imami
- RIKEN Center for Integrative Medical Sciences, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiraku Takada
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555, Japan
| | - Yasushi Ishihama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shinobu Chiba
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555, Japan
| | - Yuichiro Mishima
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555, Japan
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23
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Lyons EF, Devanneaux LC, Muller RY, Freitas AV, Meacham ZA, McSharry MV, Trinh VN, Rogers AJ, Ingolia NT, Lareau LF. Codon optimality modulates protein output by tuning translation initiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.27.568910. [PMID: 38076849 PMCID: PMC10705293 DOI: 10.1101/2023.11.27.568910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The impact of synonymous codon choice on protein output has important implications for understanding endogenous gene expression and design of synthetic mRNAs. Previously, we used a neural network model to design a series of synonymous fluorescent reporters whose protein output in yeast spanned a seven-fold range corresponding to their predicted translation speed. Here, we show that this effect is not due primarily to the established impact of slow elongation on mRNA stability, but rather, that an active mechanism further decreases the number of proteins made per mRNA. We combine simulations and careful experiments on fluorescent reporters to argue that translation initiation is limited on non-optimally encoded transcripts. Using a genome-wide CRISPRi screen to discover factors modulating the output from non-optimal transcripts, we identify a set of translation initiation factors including multiple subunits of eIF3 whose depletion restored protein output of a non-optimal reporter. Our results show that codon usage can directly limit protein production, across the full range of endogenous variability in codon usage, by limiting translation initiation.
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Affiliation(s)
| | | | | | | | | | | | - Van N Trinh
- Department of Bioengineering, University of California, Berkeley
| | | | | | - Liana F Lareau
- Department of Molecular and Cell Biology
- California Institute for Quantitative Biosciences
- Department of Bioengineering, University of California, Berkeley
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24
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Alagar Boopathy LR, Beadle E, Garcia-Bueno Rico A, Vera M. Proteostasis regulation through ribosome quality control and no-go-decay. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1809. [PMID: 37488089 DOI: 10.1002/wrna.1809] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 06/14/2023] [Accepted: 06/30/2023] [Indexed: 07/26/2023]
Abstract
Cell functionality relies on the existing pool of proteins and their folding into functional conformations. This is achieved through the regulation of protein synthesis, which requires error-free mRNAs and ribosomes. Ribosomes are quality control hubs for mRNAs and proteins. Problems during translation elongation slow down the decoding rate, leading to ribosome halting and the eventual collision with the next ribosome. Collided ribosomes form a specific disome structure recognized and solved by ribosome quality control (RQC) mechanisms. RQC pathways orchestrate the degradation of the problematic mRNA by no-go decay and the truncated nascent peptide, the repression of translation initiation, and the recycling of the stalled ribosomes. All these events maintain protein homeostasis and return valuable ribosomes to translation. As such, cell homeostasis and function are maintained at the mRNA level by preventing the production of aberrant or unnecessary proteins. It is becoming evident that the crosstalk between RQC and the protein homeostasis network is vital for cell function, as the absence of RQC components leads to the activation of stress response and neurodegenerative diseases. Here, we review the molecular events of RQC discovered through well-designed stalling reporters. Given the impact of RQC in proteostasis, we discuss the relevance of identifying endogenous mRNA regulated by RQC and their preservation in stress conditions. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms Translation > Regulation.
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Affiliation(s)
| | - Emma Beadle
- Department of Biochemistry, McGill University, Montreal, Canada
| | | | - Maria Vera
- Department of Biochemistry, McGill University, Montreal, Canada
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25
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Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
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Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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26
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Iyer KV, Müller M, Tittel LS, Winz ML. Molecular Highway Patrol for Ribosome Collisions. Chembiochem 2023; 24:e202300264. [PMID: 37382189 DOI: 10.1002/cbic.202300264] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/25/2023] [Accepted: 06/28/2023] [Indexed: 06/30/2023]
Abstract
During translation, messenger RNAs (mRNAs) are decoded by ribosomes which can stall for various reasons. These include chemical damage, codon composition, starvation, or translation inhibition. Trailing ribosomes can collide with stalled ribosomes, potentially leading to dysfunctional or toxic proteins. Such aberrant proteins can form aggregates and favor diseases, especially neurodegeneration. To prevent this, both eukaryotes and bacteria have evolved different pathways to remove faulty nascent peptides, mRNAs and defective ribosomes from the collided complex. In eukaryotes, ubiquitin ligases play central roles in triggering downstream responses and several complexes have been characterized that split affected ribosomes and facilitate degradation of the various components. As collided ribosomes signal translation stress to affected cells, in eukaryotes additional stress response pathways are triggered when collisions are sensed. These pathways inhibit translation and modulate cell survival and immune responses. Here, we summarize the current state of knowledge about rescue and stress response pathways triggered by ribosome collisions.
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Affiliation(s)
- Kaushik Viswanathan Iyer
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5, 55128, Mainz, Germany
| | - Max Müller
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5, 55128, Mainz, Germany
| | - Lena Sophie Tittel
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5, 55128, Mainz, Germany
| | - Marie-Luise Winz
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5, 55128, Mainz, Germany
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27
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Gurzeler LA, Link M, Ibig Y, Schmidt I, Galuba O, Schoenbett J, Gasser-Didierlaurant C, Parker CN, Mao X, Bitsch F, Schirle M, Couttet P, Sigoillot F, Ziegelmüller J, Uldry AC, Teodorowicz W, Schmiedeberg N, Mühlemann O, Reinhardt J. Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control. Cell Rep 2023; 42:113056. [PMID: 37651229 DOI: 10.1016/j.celrep.2023.113056] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/15/2023] [Accepted: 08/16/2023] [Indexed: 09/02/2023] Open
Abstract
Suppression of premature termination codons (PTCs) by translational readthrough is a promising strategy to treat a wide variety of severe genetic diseases caused by nonsense mutations. Here, we present two potent readthrough promoters-NVS1.1 and NVS2.1-that restore substantial levels of functional full-length CFTR and IDUA proteins in disease models for cystic fibrosis and Hurler syndrome, respectively. In contrast to other readthrough promoters that affect stop codon decoding, the NVS compounds stimulate PTC suppression by triggering rapid proteasomal degradation of the translation termination factor eRF1. Our results show that this occurs by trapping eRF1 in the terminating ribosome, causing ribosome stalls and subsequent ribosome collisions, and activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25.
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Affiliation(s)
- Lukas-Adrian Gurzeler
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Marion Link
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Yvonne Ibig
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Isabel Schmidt
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Olaf Galuba
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | | | - Xiaohong Mao
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Francis Bitsch
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Markus Schirle
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Philipp Couttet
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Jana Ziegelmüller
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Wojciech Teodorowicz
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
| | - Jürgen Reinhardt
- Novartis Institutes for BioMedical Research, Basel, Switzerland.
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28
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Chen H, Pan T, Zheng X, Huang Y, Wu C, Yang T, Gao S, Wang L, Yan S. The ATR-WEE1 kinase module promotes SUPPRESSOR OF GAMMA RESPONSE 1 translation to activate replication stress responses. THE PLANT CELL 2023; 35:3021-3034. [PMID: 37159556 PMCID: PMC10396359 DOI: 10.1093/plcell/koad126] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/11/2023]
Abstract
DNA replication stress threatens genome stability and is a hallmark of cancer in humans. The evolutionarily conserved kinases ATR (ATM and RAD3-related) and WEE1 are essential for the activation of replication stress responses. Translational control is an important mechanism that regulates gene expression, but its role in replication stress responses is largely unknown. Here we show that ATR-WEE1 control the translation of SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a master transcription factor required for replication stress responses in Arabidopsis thaliana. Through genetic screening, we found that the loss of GENERAL CONTROL NONDEREPRESSIBLE 20 (GCN20) or GCN1, which function together to inhibit protein translation, suppressed the hypersensitivity of the atr or wee1 mutant to replication stress. Biochemically, WEE1 inhibits GCN20 by phosphorylating it; phosphorylated GCN20 is subsequently polyubiquitinated and degraded. Ribosome profiling experiments revealed that that loss of GCN20 enhanced the translation efficiency of SOG1, while overexpressing GCN20 had the opposite effect. The loss of SOG1 reduced the resistance of wee1 gcn20 to replication stress, whereas overexpressing SOG1 enhanced the resistance to atr or wee1 to replication stress. These results suggest that ATR-WEE1 inhibits GCN20-GCN1 activity to promote the translation of SOG1 during replication stress. These findings link translational control to replication stress responses in Arabidopsis.
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Affiliation(s)
- Hanchen Chen
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Ting Pan
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Xueao Zheng
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Yongchi Huang
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Chong Wu
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Tongbin Yang
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Shan Gao
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Lili Wang
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Shunping Yan
- Hubei Hongshan Laboratory, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen 518000, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Shenzhen 518000, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
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29
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Ryder L, Arendrup FS, Martínez JF, Snieckute G, Pecorari C, Shah RA, Lund AH, Blasius M, Bekker-Jensen S. Nitric oxide-induced ribosome collision activates ribosomal surveillance mechanisms. Cell Death Dis 2023; 14:467. [PMID: 37495584 PMCID: PMC10372077 DOI: 10.1038/s41419-023-05997-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 06/23/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023]
Abstract
Impairment of protein translation can cause stalling and collision of ribosomes and is a signal for the activation of ribosomal surveillance and rescue pathways. Despite clear evidence that ribosome collision occurs stochastically at a cellular and organismal level, physiologically relevant sources of such aberrations are poorly understood. Here we show that a burst of the cellular signaling molecule nitric oxide (NO) reduces translational activity and causes ribosome collision in human cell lines. This is accompanied by activation of the ribotoxic stress response, resulting in ZAKα-mediated activation of p38 and JNK kinases. In addition, NO production is associated with ZNF598-mediated ubiquitination of the ribosomal protein RPS10 and GCN2-mediated activation of the integrated stress response, which are well-described responses to the collision of ribosomes. In sum, our work implicates a novel role of NO as an inducer of ribosome collision and activation of ribosomal surveillance mechanisms in human cells.
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Affiliation(s)
- Laura Ryder
- Center for Healthy Aging, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Frederic Schrøder Arendrup
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark
| | - José Francisco Martínez
- Center for Healthy Aging, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Goda Snieckute
- Center for Healthy Aging, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Chiara Pecorari
- Danish Cancer Society Research Center, Strandboulevarden 49, DK-2100, Copenhagen, Denmark
| | - Riyaz Ahmad Shah
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Anders H Lund
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark
| | - Melanie Blasius
- Center for Healthy Aging, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Simon Bekker-Jensen
- Center for Healthy Aging, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark.
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark.
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30
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Barros GC, Guerrero S, Silva GM. The central role of translation elongation in response to stress. Biochem Soc Trans 2023; 51:959-969. [PMID: 37318088 PMCID: PMC11160351 DOI: 10.1042/bst20220584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Protein synthesis is essential to support homeostasis, and thus, must be highly regulated during cellular response to harmful environments. All stages of translation are susceptible to regulation under stress, however, the mechanisms involved in translation regulation beyond initiation have only begun to be elucidated. Methodological advances enabled critical discoveries on the control of translation elongation, highlighting its important role in translation repression and the synthesis of stress-response proteins. In this article, we discuss recent findings on mechanisms of elongation control mediated by ribosome pausing and collisions and the availability of tRNAs and elongation factors. We also discuss how elongation intersects with distinct modes of translation control, further supporting cellular viability and gene expression reprogramming. Finally, we highlight how several of these pathways are reversibly regulated, emphasizing the dynamics of translation control during stress-response progression. A comprehensive understanding of translation regulation under stress will produce fundamental knowledge of protein dynamics while opening new avenues and strategies to overcome dysregulated protein production and cellular sensitivity to stress.
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Affiliation(s)
| | | | - Gustavo M. Silva
- Department of Biology, Duke University, Durham, NC, USA
- Lead contact
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31
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Jennings MD, Srivastava P, Kershaw CJ, Talavera D, Grant C, Pavitt G. Interaction of the La-related protein Slf1 with colliding ribosomes maintains translation of oxidative-stress responsive mRNAs. Nucleic Acids Res 2023; 51:5755-5773. [PMID: 37070186 PMCID: PMC10287931 DOI: 10.1093/nar/gkad272] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/19/2023] Open
Abstract
In response to oxidative stress cells reprogram gene expression to enhance levels of antioxidant enzymes and promote survival. In Saccharomyces cerevisiae the polysome-interacting La-related proteins (LARPs) Slf1 and Sro9 aid adaptation of protein synthesis during stress by undetermined means. To gain insight in their mechanisms of action in stress responses, we determined LARP mRNA binding positions in stressed and unstressed cells. Both proteins bind within coding regions of stress-regulated antioxidant enzyme and other highly translated mRNAs in both optimal and stressed conditions. LARP interaction sites are framed and enriched with ribosome footprints suggesting ribosome-LARP-mRNA complexes are identified. Although stress-induced translation of antioxidant enzyme mRNAs is attenuated in slf1Δ, these mRNAs remain on polysomes. Focusing further on Slf1, we find it binds to both monosomes and disomes following RNase treatment. slf1Δ reduces disome enrichment during stress and alters programmed ribosome frameshifting rates. We propose that Slf1 is a ribosome-associated translational modulator that stabilises stalled/collided ribosomes, prevents ribosome frameshifting and so promotes translation of a set of highly-translated mRNAs that together facilitate cell survival and adaptation to stress.
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Affiliation(s)
- Martin D Jennings
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - Priya Srivastava
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - Christopher J Kershaw
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - David Talavera
- Division of Cardiovascular Sciences, School of Medical Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - Christopher M Grant
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, M13 9PT, UK
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32
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Müller MBD, Kasturi P, Jayaraj GG, Hartl FU. Mechanisms of readthrough mitigation reveal principles of GCN1-mediated translational quality control. Cell 2023:S0092-8674(23)00587-1. [PMID: 37339632 PMCID: PMC10364623 DOI: 10.1016/j.cell.2023.05.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 05/17/2023] [Accepted: 05/24/2023] [Indexed: 06/22/2023]
Abstract
Readthrough into the 3' untranslated region (3' UTR) of the mRNA results in the production of aberrant proteins. Metazoans efficiently clear readthrough proteins, but the underlying mechanisms remain unknown. Here, we show in Caenorhabditis elegans and mammalian cells that readthrough proteins are targeted by a coupled, two-level quality control pathway involving the BAG6 chaperone complex and the ribosome-collision-sensing protein GCN1. Readthrough proteins with hydrophobic C-terminal extensions (CTEs) are recognized by SGTA-BAG6 and ubiquitylated by RNF126 for proteasomal degradation. Additionally, cotranslational mRNA decay initiated by GCN1 and CCR4/NOT limits the accumulation of readthrough products. Unexpectedly, selective ribosome profiling uncovered a general role of GCN1 in regulating translation dynamics when ribosomes collide at nonoptimal codons, enriched in 3' UTRs, transmembrane proteins, and collagens. GCN1 dysfunction increasingly perturbs these protein classes during aging, resulting in mRNA and proteome imbalance. Our results define GCN1 as a key factor acting during translation in maintaining protein homeostasis.
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Affiliation(s)
- Martin B D Müller
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Prasad Kasturi
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Gopal G Jayaraj
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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Hurtig JE, van Hoof A. An unknown essential function of tRNA splicing endonuclease is linked to the integrated stress response and intron debranching. Genetics 2023; 224:iyad044. [PMID: 36943791 PMCID: PMC10213494 DOI: 10.1093/genetics/iyad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 10/31/2022] [Accepted: 03/09/2023] [Indexed: 03/23/2023] Open
Abstract
tRNA splicing endonuclease (TSEN) has a well-characterized role in transfer RNA (tRNA) splicing but also other functions. For yeast TSEN, these other functions include degradation of a subset of mRNAs that encode mitochondrial proteins and an unknown essential function. In this study, we use yeast genetics to characterize the unknown tRNA-independent function(s) of TSEN. Using a high-copy suppressor screen, we found that sen2 mutants can be suppressed by overexpression of SEN54. This effect was seen both for tRNA-dependent and tRNA-independent functions indicating that SEN54 is a general suppressor of sen2, likely through structural stabilization. A spontaneous suppressor screen identified mutations in the intron-debranching enzyme, Dbr1, as tRNA splicing-independent suppressors. Transcriptome analysis showed that sen2 mutation activates the Gcn4 stress response. These Gcn4 target transcripts decreased considerably in the sen2 dbr1 double mutant. We propose that Dbr1 and TSEN may compete for a shared substrate, which TSEN normally processes into an essential RNA, while Dbr1 initiates its degradation. These data provide further insight into the essential function(s) of TSEN. Importantly, single amino acid mutations in TSEN cause the generally fatal neuronal disease pontocerebellar hypoplasia (PCH). The mechanism by which defects in TSEN cause this disease is unknown, and our results reveal new possible mechanisms.
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Affiliation(s)
- Jennifer E Hurtig
- Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ambro van Hoof
- Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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Knowles CM, Goich D, Bloom ALM, Kalem MC, Panepinto JC. Contributions of Ccr4 and Gcn2 to the Translational Response of C. neoformans to Host-Relevant Stressors and Integrated Stress Response Induction. mBio 2023; 14:e0019623. [PMID: 37017529 PMCID: PMC10127693 DOI: 10.1128/mbio.00196-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/06/2023] [Indexed: 04/06/2023] Open
Abstract
In response to the host environment, the human pathogen Cryptococcus neoformans must rapidly reprogram its translatome from one which promotes growth to one which is responsive to host stress. In this study, we investigate the two events which comprise translatome reprogramming: the removal of abundant, pro-growth mRNAs from the translating pool, and the regulated entry of stress-responsive mRNAs into the translating pool. Removal of pro-growth mRNAs from the translating pool is controlled primarily by two regulatory mechanisms, repression of translation initiation via Gcn2, and decay mediated by Ccr4. We determined that translatome reprogramming in response to oxidative stress requires both Gcn2 and Ccr4, whereas the response to temperature requires only Ccr4. Additionally, we assessed ribosome collision in response to host-relevant stress and found that collided ribosomes accumulated during temperature stress but not during oxidative stress. The phosphorylation of eIF2α that occurred as a result of translational stress led us to investigate the induction of the integrated stress response (ISR). We found that eIF2α phosphorylation varied in response to the type and magnitude of stress, yet all tested conditions induced translation of the ISR transcription factor Gcn4. However, Gcn4 translation did not necessarily result in canonical Gcn4-dependent transcription. Finally, we define the ISR regulon in response to oxidative stress. In conclusion, this study begins to reveal the translational regulation in response to host-relevant stressors in an environmental fungus which is capable of adapting to the environment inside the human host. IMPORTANCE Cryptococcus neoformans is a human pathogen capable of causing devastating infections. It must rapidly adapt to changing environments as it leaves its niche in the soil and enters the human lung. Previous work has demonstrated a need to reprogram gene expression at the level of translation to promote stress adaptation. In this work, we investigate the contributions and interplay of the major mechanisms that regulate entry of new mRNAs into the pool (translation initiation) and the clearance of unneeded mRNAs from the pool (mRNA decay). One result of this reprogramming is the induction of the integrated stress response (ISR) regulon. Surprisingly, all stresses tested led to the production of the ISR transcription factor Gcn4, but not necessarily to transcription of ISR target genes. Furthermore, stresses result in differential levels of ribosome collisions, but these are not necessarily predictive of initiation repression as has been suggested in the model yeast.
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Affiliation(s)
- Corey M. Knowles
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - David Goich
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Amanda L. M. Bloom
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Murat C. Kalem
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - John C. Panepinto
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
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Gupta R, Hinnebusch AG. Differential requirements for P stalk components in activating yeast protein kinase Gcn2 by stalled ribosomes during stress. Proc Natl Acad Sci U S A 2023; 120:e2300521120. [PMID: 37043534 PMCID: PMC10120022 DOI: 10.1073/pnas.2300521120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/13/2023] [Indexed: 04/13/2023] Open
Abstract
The General Amino Acid Control is a conserved response to amino acid starvation involving activation of protein kinase Gcn2, which phosphorylates eukaryotic initiation factor 2 (eIF2α) with attendant inhibition of global protein synthesis and increased translation of yeast transcriptional activator GCN4. Gcn2 can be activated by either amino acid starvation or conditions that stall elongating ribosomes without reducing aminoacylation of tRNA, but it is unclear whether distinct molecular mechanisms operate in these two circumstances. We identified three regimes that activate Gcn2 in yeast cells by starvation-independent (SI) ribosome-stalling: treatment with tigecycline, eliminating the sole gene encoding tRNAArgUCC, and depletion of translation termination factor eRF1. We further demonstrated requirements for the tRNA- and ribosome-binding domains of Gcn2, the positive effector proteins Gcn1/Gcn20, and the tethering of at least one of two distinct P1/P2 heterodimers to the uL10 subunit of the ribosomal P stalk, for detectable activation by SI-ribosome stalling. Remarkably, no tethered P1/P2 proteins were required for strong Gcn2 activation elicited by starvation for histidine or branched-chain amino acids isoleucine/valine. These results indicate that Gcn2 activation has different requirements for the P stalk depending on how ribosomes are stalled. We propose that accumulation of deacylated tRNAs in amino acid-starved cells can functionally substitute for the P stalk in binding to the histidyl-tRNA synthetase-like domain of Gcn2 for eIF2α kinase activation by ribosomes stalled with A sites devoid of the eEF1A∙GTP∙aminoacyl-tRNA ternary complex.
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Affiliation(s)
- Ritu Gupta
- Section on Nutrient Control of Gene Expression, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
| | - Alan G. Hinnebusch
- Section on Nutrient Control of Gene Expression, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
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Carlson KR, Georgiadis MM, Tameire F, Staschke KA, Wek RC. Activation of Gcn2 by small molecules designed to be inhibitors. J Biol Chem 2023; 299:104595. [PMID: 36898579 PMCID: PMC10124904 DOI: 10.1016/j.jbc.2023.104595] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/06/2023] [Indexed: 03/10/2023] Open
Abstract
The integrated stress response (ISR) is an important mechanism by which cells confer protection against environmental stresses. Central to the ISR is a collection of related protein kinases that monitor stress conditions, such as Gcn2 (EIF2AK4) that recognizes nutrient limitations, inducing phosphorylation of eukaryotic translation initiation factor 2 (eIF2). Gcn2 phosphorylation of eIF2 lowers bulk protein synthesis, conserving energy and nutrients, coincident with preferential translation of stress-adaptive gene transcripts, such as that encoding the Atf4 transcriptional regulator. While Gcn2 is central for cell protection to nutrient stress and its depletion in humans leads to pulmonary disorders, Gcn2 can also contribute to the progression of cancers and facilitate neurological disorders during chronic stress. Consequently, specific ATP-competitive inhibitors of Gcn2 protein kinase have been developed. In this study, we report that one such Gcn2 inhibitor, Gcn2iB, can activate Gcn2, and we probe the mechanism by which this activation occurs. Low concentrations of Gcn2iB increase Gcn2 phosphorylation of eIF2 and enhance Atf4 expression and activity. Of importance, Gcn2iB can activate Gcn2 mutants devoid of functional regulatory domains or with certain kinase domain substitutions derived from Gcn2-deficient human patients. Other ATP-competitive inhibitors can also activate Gcn2, although there are differences in their mechanisms of activation. These results provide a cautionary note about the pharmacodynamics of eIF2 kinase inhibitors in therapeutic applications. Compounds designed to be kinase inhibitors that instead directly activate Gcn2, even loss of function variants, may provide tools to alleviate deficiencies in Gcn2 and other regulators of the ISR.
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Affiliation(s)
- Kenneth R Carlson
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | | | - Kirk A Staschke
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA.
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Wątor E, Wilk P, Biela A, Rawski M, Zak KM, Steinchen W, Bange G, Glatt S, Grudnik P. Cryo-EM structure of human eIF5A-DHS complex reveals the molecular basis of hypusination-associated neurodegenerative disorders. Nat Commun 2023; 14:1698. [PMID: 36973244 PMCID: PMC10042821 DOI: 10.1038/s41467-023-37305-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 03/09/2023] [Indexed: 03/29/2023] Open
Abstract
Hypusination is a unique post-translational modification of the eukaryotic translation factor 5A (eIF5A) that is essential for overcoming ribosome stalling at polyproline sequence stretches. The initial step of hypusination, the formation of deoxyhypusine, is catalyzed by deoxyhypusine synthase (DHS), however, the molecular details of the DHS-mediated reaction remained elusive. Recently, patient-derived variants of DHS and eIF5A have been linked to rare neurodevelopmental disorders. Here, we present the cryo-EM structure of the human eIF5A-DHS complex at 2.8 Å resolution and a crystal structure of DHS trapped in the key reaction transition state. Furthermore, we show that disease-associated DHS variants influence the complex formation and hypusination efficiency. Hence, our work dissects the molecular details of the deoxyhypusine synthesis reaction and reveals how clinically-relevant mutations affect this crucial cellular process.
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Affiliation(s)
- Elżbieta Wątor
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Kraków, Poland
| | - Piotr Wilk
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Artur Biela
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Michał Rawski
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Krzysztof M Zak
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Wieland Steinchen
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
- Max Planck Institute for Terrestrial Microbiology, Molecular Physiology of Microbes, Marburg, Germany
| | - Sebastian Glatt
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Przemysław Grudnik
- Małopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland.
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Fedry J, Silva J, Vanevic M, Fronik S, Mechulam Y, Schmitt E, des Georges A, Faller W, Förster F. Visualization of translation reorganization upon persistent collision stress in mammalian cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533914. [PMID: 36993420 PMCID: PMC10055323 DOI: 10.1101/2023.03.23.533914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Aberrantly slow mRNA translation leads to ribosome stalling and subsequent collision with the trailing neighbor. Ribosome collisions have recently been shown to act as stress sensors in the cell, with the ability to trigger stress responses balancing survival and apoptotic cell-fate decisions depending on the stress level. However, we lack a molecular understanding of the reorganization of translation processes over time in mammalian cells exposed to an unresolved collision stress. Here we visualize the effect of a persistent collision stress on translation using in situ cryo electron tomography. We observe that low dose anisomycin collision stress leads to the stabilization of Z-site bound tRNA on elongating 80S ribosomes, as well as to the accumulation of an off-pathway 80S complex possibly resulting from collision splitting events. We visualize collided disomes in situ, occurring on compressed polysomes and revealing a stabilized geometry involving the Z-tRNA and L1 stalk on the stalled ribosome, and eEF2 bound to its collided rotated-2 neighbor. In addition, non-functional post-splitting 60S complexes accumulate in the stressed cells, indicating a limiting Ribosome associated Quality Control clearing rate. Finally, we observe the apparition of tRNA-bound aberrant 40S complexes shifting with the stress timepoint, suggesting a succession of different initiation inhibition mechanisms over time. Altogether, our work visualizes the changes of translation complexes under persistent collision stress in mammalian cells, indicating how perturbations in initiation, elongation and quality control processes contribute to an overall reduced protein synthesis.
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Affiliation(s)
- Juliette Fedry
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Joana Silva
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Mihajlo Vanevic
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Stanley Fronik
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Amédée des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, City University of New York, New York, NY, USA
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY, USA
- Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center, City University of New York, New York, NY, USA
| | - William Faller
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
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Martínez-Férriz A, Gandía C, Pardo-Sánchez JM, Fathinajafabadi A, Ferrando A, Farràs R. Eukaryotic Initiation Factor 5A2 localizes to actively translating ribosomes to promote cancer cell protrusions and invasive capacity. Cell Commun Signal 2023; 21:54. [PMID: 36915194 PMCID: PMC10009989 DOI: 10.1186/s12964-023-01076-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/11/2023] [Indexed: 03/14/2023] Open
Abstract
BACKGROUND Eukaryotic Initiation Factor 5A (eIF-5A), an essential translation factor, is post-translationally activated by the polyamine spermidine. Two human genes encode eIF-5A, being eIF5-A1 constitutively expressed whereas eIF5-A2 is frequently found overexpressed in human tumours. The contribution of both isoforms with regard to cellular proliferation and invasion in non-small cell lung cancer remains to be characterized. METHODS We have evaluated the use of eIF-5A2 gene as prognosis marker in lung adenocarcinoma (LUAD) patients and validated in immunocompromised mice. We have used cell migration and cell proliferation assays in LUAD lines after silencing each eIF-5A isoform to monitor their contribution to both phenotypes. Cytoskeleton alterations were analysed in the same cells by rhodamine-phalloidin staining and fluorescence microscopy. Polysome profiles were used to monitor the effect of eIF-5A2 overexpression on translation. Western blotting was used to study the levels of eIF-5A2 client proteins involved in migration upon TGFB1 stimulation. Finally, we have co-localized eIF-5A2 with puromycin to visualize the subcellular pattern of actively translating ribosomes. RESULTS We describe the differential functions of both eIF-5A isoforms, to show that eIF5-A2 properties on cell proliferation and migration are coincident with its features as a poor prognosis marker. Silencing of eIF-5A2 leads to more dramatic consequences of cellular proliferation and migration compared to eIF-5A1. Overexpression of eIF-5A2 leads to enhanced global translation. We also show that TGFβ signalling enhances the expression and activity of eIF-5A2 which promotes the translation of polyproline rich proteins involved in cytoskeleton and motility features as it is the case of Fibronectin, SNAI1, Ezrin and FHOD1. With the use of puromycin labelling we have co-localized active ribosomes with eIF-5A2 not only in cytosol but also in areas of cellular protrusion. We have shown the bulk invasive capacity of cells overexpressing eIF-5A2 in mice. CONCLUSIONS We propose the existence of a coordinated temporal and positional interaction between TFGB and eIF-5A2 pathways to promote cell migration in NSCLC. We suggest that the co-localization of actively translating ribosomes with hypusinated eIF-5A2 facilitates the translation of key proteins not only in the cytosol but also in areas of cellular protrusion. Video Abstract.
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Affiliation(s)
| | | | | | | | - Alejandro Ferrando
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas. Universidad Politécnica de Valencia, 46022, Valencia, Spain
| | - Rosa Farràs
- Centro de Investigación Príncipe Felipe, Valencia, Spain.
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40
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Matsuo Y, Inada T. Co-Translational Quality Control Induced by Translational Arrest. Biomolecules 2023; 13:biom13020317. [PMID: 36830686 PMCID: PMC9953336 DOI: 10.3390/biom13020317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/19/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Genetic mutations, mRNA processing errors, and lack of availability of charged tRNAs sometimes slow down or completely stall translating ribosomes. Since an incomplete nascent chain derived from stalled ribosomes may function anomalously, such as by forming toxic aggregates, surveillance systems monitor every step of translation and dispose of such products to prevent their accumulation. Over the past decade, yeast models with powerful genetics and biochemical techniques have contributed to uncovering the mechanism of the co-translational quality control system, which eliminates the harmful products generated from aberrant translation. We here summarize the current knowledge of the molecular mechanism of the co-translational quality control systems in yeast, which eliminate the incomplete nascent chain, improper mRNAs, and faulty ribosomes to maintain cellular protein homeostasis.
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41
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Oltion K, Carelli JD, Yang T, See SK, Wang HY, Kampmann M, Taunton J. An E3 ligase network engages GCN1 to promote the degradation of translation factors on stalled ribosomes. Cell 2023; 186:346-362.e17. [PMID: 36638793 PMCID: PMC9994462 DOI: 10.1016/j.cell.2022.12.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 11/29/2022] [Accepted: 12/13/2022] [Indexed: 01/14/2023]
Abstract
Ribosomes frequently stall during mRNA translation, resulting in the context-dependent activation of quality control pathways to maintain proteostasis. However, surveillance mechanisms that specifically respond to stalled ribosomes with an occluded A site have not been identified. We discovered that the elongation factor-1α (eEF1A) inhibitor, ternatin-4, triggers the ubiquitination and degradation of eEF1A on stalled ribosomes. Using a chemical genetic approach, we unveiled a signaling network comprising two E3 ligases, RNF14 and RNF25, which are required for eEF1A degradation. Quantitative proteomics revealed the RNF14 and RNF25-dependent ubiquitination of eEF1A and a discrete set of ribosomal proteins. The ribosome collision sensor GCN1 plays an essential role by engaging RNF14, which directly ubiquitinates eEF1A. The site-specific, RNF25-dependent ubiquitination of the ribosomal protein RPS27A/eS31 provides a second essential signaling input. Our findings illuminate a ubiquitin signaling network that monitors the ribosomal A site and promotes the degradation of stalled translation factors, including eEF1A and the termination factor eRF1.
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Affiliation(s)
- Keely Oltion
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jordan D Carelli
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tangpo Yang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stephanie K See
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hao-Yuan Wang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Martin Kampmann
- Institute for Neurodegenerative Diseases, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA.
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42
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Sabbarini IM, Reif D, McQuown AJ, Nelliat AR, Prince J, Membreno BS, Wu CCC, Murray AW, Denic V. Zinc-finger protein Zpr1 is a bespoke chaperone essential for eEF1A biogenesis. Mol Cell 2023; 83:252-265.e13. [PMID: 36630955 PMCID: PMC10016025 DOI: 10.1016/j.molcel.2022.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/15/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023]
Abstract
The conserved regulon of heat shock factor 1 in budding yeast contains chaperones for general protein folding as well as zinc-finger protein Zpr1, whose essential role in archaea and eukaryotes remains unknown. Here, we show that Zpr1 depletion causes acute proteotoxicity driven by biosynthesis of misfolded eukaryotic translation elongation factor 1A (eEF1A). Prolonged Zpr1 depletion leads to eEF1A insufficiency, thereby inducing the integrated stress response and inhibiting protein synthesis. Strikingly, we show by using two distinct biochemical reconstitution approaches that Zpr1 enables eEF1A to achieve a conformational state resistant to protease digestion. Lastly, we use a ColabFold model of the Zpr1-eEF1A complex to reveal a folding mechanism mediated by the Zpr1's zinc-finger and alpha-helical hairpin structures. Our work uncovers the long-sought-after function of Zpr1 as a bespoke chaperone tailored to the biogenesis of one of the most abundant proteins in the cell.
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Affiliation(s)
- Ibrahim M Sabbarini
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Dvir Reif
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Alexander J McQuown
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anjali R Nelliat
- Graduate Program in Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey Prince
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Britnie Santiago Membreno
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Colin Chih-Chien Wu
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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Decoding of the ubiquitin code for clearance of colliding ribosomes by the RQT complex. Nat Commun 2023; 14:79. [PMID: 36627279 PMCID: PMC9831982 DOI: 10.1038/s41467-022-35608-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
The collision sensor Hel2 specifically recognizes colliding ribosomes and ubiquitinates the ribosomal protein uS10, leading to noncanonical subunit dissociation by the ribosome-associated quality control trigger (RQT) complex. Although uS10 ubiquitination is essential for rescuing stalled ribosomes, its function and recognition steps are not fully understood. Here, we show that the RQT complex components Cue3 and Rqt4 interact with the K63-linked ubiquitin chain and accelerate the recruitment of the RQT complex to the ubiquitinated colliding ribosome. The CUE domain of Cue3 and the N-terminal domain of Rqt4 bind independently to the K63-linked ubiquitin chain. Their deletion abolishes ribosomal dissociation mediated by the RQT complex. High-speed atomic force microscopy (HS-AFM) reveals that the intrinsically disordered regions of Rqt4 enable the expansion of the searchable area for interaction with the ubiquitin chain. These findings provide mechanistic insight into the decoding of the ubiquitin code for clearance of colliding ribosomes by the RQT complex.
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44
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Baymukhametov TN, Lyabin DN, Chesnokov YM, Sorokin II, Pechnikova E, Vasiliev A, Afonina Z. Polyribosomes of circular topology are prevalent in mammalian cells. Nucleic Acids Res 2022; 51:908-918. [PMID: 36583341 PMCID: PMC9881139 DOI: 10.1093/nar/gkac1208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/31/2022] Open
Abstract
Polyribosomes, the groups of ribosomes simultaneously translating a single mRNA molecule, are very common in both, prokaryotic and eukaryotic cells. Even in early EM studies, polyribosomes have been shown to possess various spatial conformations, including a ring-shaped configuration which was considered to be functionally important. However, a recent in situ cryo-ET analysis of predominant regular inter-ribosome contacts did not confirm the abundance of ring-shaped polyribosomes in a cell cytoplasm. To address this discrepancy, here we analyzed the cryo-ET structure of polyribosomes in diluted lysates of HeLa cells. It was shown that the vast majority of the ribosomes were combined into polysomes and were proven to be translationally active. Tomogram analysis revealed that circular polyribosomes are indeed very common in the cytoplasm, but they mostly possess pseudo-regular structures without specific inter-ribosomal contacts. Although the size of polyribosomes varied widely, most circular polysomes were relatively small in size (4-8 ribosomes). Our results confirm the recent data that it is cellular mRNAs with short ORF that most commonly form circular structures providing an enhancement of translation.
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Affiliation(s)
- Timur N Baymukhametov
- Structural biology department, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia
| | - Dmitry N Lyabin
- Institute of Protein Research RAS, Pushchino, Moscow Region 142290, Russia
| | - Yury M Chesnokov
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia
| | - Ivan I Sorokin
- Institute of Protein Research RAS, Pushchino, Moscow Region 142290, Russia
| | - Evgeniya V Pechnikova
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia,Electron Microscopy Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre ‘Crystallography and Photonics’ RAS, Moscow 119333, Russia
| | - Alexander L Vasiliev
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia,Electron Microscopy Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre ‘Crystallography and Photonics’ RAS, Moscow 119333, Russia
| | - Zhanna A Afonina
- To whom correspondence should be addressed. Tel: +7 985 7232812; Fax: +7 4967 318435;
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45
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Tomomatsu S, Watanabe A, Tesina P, Hashimoto S, Ikeuchi K, Li S, Matsuo Y, Beckmann R, Inada T. Two modes of Cue2-mediated mRNA cleavage with distinct substrate recognition initiate no-go decay. Nucleic Acids Res 2022; 51:253-270. [PMID: 36583309 PMCID: PMC9841427 DOI: 10.1093/nar/gkac1172] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/17/2022] [Accepted: 11/25/2022] [Indexed: 12/31/2022] Open
Abstract
Ribosome collisions are recognized by E3 ubiquitin ligase Hel2/ZNF598, leading to RQC (ribosome-associated quality control) and to endonucleolytic cleavage and degradation of the mRNA termed NGD (no-go decay). NGD in yeast requires the Cue2 endonuclease and occurs in two modes, either coupled to RQC (NGDRQC+) or RQC uncoupled (NGDRQC-). This is mediated by an unknown mechanism of substrate recognition by Cue2. Here, we show that the ubiquitin binding activity of Cue2 is required for NGDRQC- but not for NGDRQC+, and that it involves the first two N-terminal Cue domains. In contrast, Trp122 of Cue2 is crucial for NGDRQC+. Moreover, Mbf1 is required for quality controls by preventing +1 ribosome frameshifting induced by a rare codon staller. We propose that in Cue2-dependent cleavage upstream of the collided ribosomes (NGDRQC-), polyubiquitination of eS7 is recognized by two N-terminal Cue domains of Cue2. In contrast, for the cleavage within collided ribosomes (NGDRQC+), the UBA domain, Trp122 and the interaction between Mbf1 and uS3 are critical.
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Affiliation(s)
| | | | - Petr Tesina
- Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Satoshi Hashimoto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ken Ikeuchi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan,Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Sihan Li
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan,Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Yoshitaka Matsuo
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan,Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Roland Beckmann
- Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Toshifumi Inada
- To whom correspondence should be addressed. Tel: +81 3 5449 5275; Fax: +81 3 5449 5275;
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46
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Is bRaQCing bad? New roles for ribosome associated quality control factors in stress granule regulation. Biochem Soc Trans 2022; 50:1715-1724. [DOI: 10.1042/bst20220549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 12/13/2022]
Abstract
Maintenance of proteostasis is of utmost importance to cellular viability and relies on the coordination of many post-transcriptional processes to respond to stressful stimuli. Stress granules (SGs) are RNA–protein condensates that form after translation initiation is inhibited, such as during the integrated stress response (ISR), and may facilitate cellular adaptation to stress. The ribosome-associated quality control (RQC) pathway is a critical translation monitoring system that recognizes aberrant mRNAs encoding potentially toxic nascent peptides to target them for degradation. Both SG regulation and the RQC pathway are directly associated with translation regulation, thus it is of no surprise recent developments have demonstrated a connection between them. VCP's function in the stress activated RQC pathway, ribosome collisions activating the ISR, and the regulation of the 40S ribosomal subunit by canonical SG proteins during the RQC all connect SGs to the RQC pathway. Because mutations in genes that are involved in both SG and RQC regulation are associated with degenerative and neurological diseases, understanding the coordination and interregulation of SGs and RQC may shed light on disease mechanisms. This minireview will highlight recent advances in understanding how SGs and the RQC pathway interact in health and disease contexts.
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47
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Jia J, Wang F, Bhujabal Z, Peters R, Mudd M, Duque T, Allers L, Javed R, Salemi M, Behrends C, Phinney B, Johansen T, Deretic V. Stress granules and mTOR are regulated by membrane atg8ylation during lysosomal damage. J Cell Biol 2022; 221:e202207091. [PMID: 36179369 PMCID: PMC9533235 DOI: 10.1083/jcb.202207091] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 01/22/2023] Open
Abstract
We report that lysosomal damage is a hitherto unknown inducer of stress granule (SG) formation and that the process termed membrane atg8ylation coordinates SG formation with mTOR inactivation during lysosomal stress. SGs were induced by lysosome-damaging agents including SARS-CoV-2ORF3a, Mycobacterium tuberculosis, and proteopathic tau. During damage, mammalian ATG8s directly interacted with the core SG proteins NUFIP2 and G3BP1. Atg8ylation was needed for their recruitment to damaged lysosomes independently of SG condensates whereupon NUFIP2 contributed to mTOR inactivation via the Ragulator-RagA/B complex. Thus, cells employ membrane atg8ylation to control and coordinate SG and mTOR responses to lysosomal damage.
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Affiliation(s)
- Jingyue Jia
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Fulong Wang
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Zambarlal Bhujabal
- Autophagy Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ryan Peters
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Michal Mudd
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Thabata Duque
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Lee Allers
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Ruheena Javed
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Michelle Salemi
- Proteomics Core Facility, University of California Davis Genome Center, University of California, Davis, Davis, CA
| | - Christian Behrends
- Munich Cluster of Systems Neurology, Ludwig-Maximilians-Universität München, München, Germany
| | - Brett Phinney
- Proteomics Core Facility, University of California Davis Genome Center, University of California, Davis, Davis, CA
| | - Terje Johansen
- Autophagy Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Vojo Deretic
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
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48
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A distinct mammalian disome collision interface harbors K63-linked polyubiquitination of uS10 to trigger hRQT-mediated subunit dissociation. Nat Commun 2022; 13:6411. [PMID: 36302773 PMCID: PMC9613687 DOI: 10.1038/s41467-022-34097-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 10/13/2022] [Indexed: 12/25/2022] Open
Abstract
Translational stalling events that result in ribosome collisions induce Ribosome-associated Quality Control (RQC) in order to degrade potentially toxic truncated nascent proteins. For RQC induction, the collided ribosomes are first marked by the Hel2/ZNF598 E3 ubiquitin ligase to recruit the RQT complex for subunit dissociation. In yeast, uS10 is polyubiquitinated by Hel2, whereas eS10 is preferentially monoubiquitinated by ZNF598 in human cells for an unknown reason. Here, we characterize the ubiquitination activity of ZNF598 and its importance for human RQT-mediated subunit dissociation using the endogenous XBP1u and poly(A) translation stallers. Cryo-EM analysis of a human collided disome reveals a distinct composite interface, with substantial differences to yeast collided disomes. Biochemical analysis of collided ribosomes shows that ZNF598 forms K63-linked polyubiquitin chains on uS10, which are decisive for mammalian RQC initiation. The human RQT (hRQT) complex composed only of ASCC3, ASCC2 and TRIP4 dissociates collided ribosomes dependent on the ATPase activity of ASCC3 and the ubiquitin-binding capacity of ASCC2. The hRQT-mediated subunit dissociation requires the K63-linked polyubiquitination of uS10, while monoubiquitination of eS10 or uS10 is not sufficient. Therefore, we conclude that ZNF598 functionally marks collided mammalian ribosomes by K63-linked polyubiquitination of uS10 for the trimeric hRQT complex-mediated subunit dissociation.
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49
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Pinch M, Muka T, Kandel Y, Lamsal M, Martinez N, Teixeira M, Boudko DY, Hansen IA. General control nonderepressible 1 interacts with cationic amino acid transporter 1 and affects Aedes aegypti fecundity. Parasit Vectors 2022; 15:383. [PMID: 36271393 PMCID: PMC9587632 DOI: 10.1186/s13071-022-05461-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 08/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The amino acid transporter protein cationic amino acid transporter 1 (CAT1) is part of the nutrient sensor in the fat body of mosquitoes. A member of the SLC7 family of cationic amino acid transporters, it is paramount for the detection of elevated amino acid levels in the mosquito hemolymph after a blood meal and the subsequent changes in gene expression in the fat body. METHODS We performed a re-annotation of Aedes aegypti cationic amino acid transporters (CATs) and selected the C-terminal tail of CAT1 to perform a yeast two-hybrid screen to identify putative interactors of this protein. One interesting interacting protein we identified was general control nonderepressible 1 (GCN1). We determined the expression pattern of GCN1 in several adult organs and structures using qRT-PCR and western blots. Finally, we knocked down GCN1 using double-stranded RNA and identified changes in downstream signaling intermediates and the effects of knockdown on vitellogenesis and fecundity. RESULTS In a screen for Ae. aegypti CAT1-interacting proteins we identified GCN1 as a putative interactor. GCN1 is highly expressed in the ovaries and fat body of the mosquito. We provide evidence that eukaryotic translation initiation factor 2 subunit alpha (eIF2α) phosphorylation changed during vitellogenesis and that RNA interference knockdown of GCN1 in whole mosquitoes reduced egg clutch sizes of treated mosquitoes relative to controls. CONCLUSIONS Aedes aegypti CAT1 and GCN1 are likely interacting partners and GCN1 is likely necessary for proper egg development. Our data suggest that GCN1 is part of a nutrient sensor mechanism in various mosquito tissues involved in vitellogenesis.
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Affiliation(s)
- Matthew Pinch
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Theodore Muka
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Yashoda Kandel
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Mahesh Lamsal
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Nathan Martinez
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | | | | | - Immo A Hansen
- Department of Biology, New Mexico State University, Las Cruces, NM, USA.
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50
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Brüggenthies JB, Fiore A, Russier M, Bitsina C, Brötzmann J, Kordes S, Menninger S, Wolf A, Conti E, Eickhoff JE, Murray PJ. A cell-based chemical-genetic screen for amino acid stress response inhibitors reveals torins reverse stress kinase GCN2 signaling. J Biol Chem 2022; 298:102629. [PMID: 36273589 PMCID: PMC9668732 DOI: 10.1016/j.jbc.2022.102629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
mTORC1 and GCN2 are serine/threonine kinases that control how cells adapt to amino acid availability. mTORC1 responds to amino acids to promote translation and cell growth while GCN2 senses limiting amino acids to hinder translation via eIF2α phosphorylation. GCN2 is an appealing target for cancer therapies because malignant cells can harness the GCN2 pathway to temper the rate of translation during rapid amino acid consumption. To isolate new GCN2 inhibitors, we created cell-based, amino acid limitation reporters via genetic manipulation of Ddit3 (encoding the transcription factor CHOP). CHOP is strongly induced by limiting amino acids and in this context, GCN2-dependent. Using leucine starvation as a model for essential amino acid sensing, we unexpectedly discovered ATP-competitive PI3 kinase-related kinase inhibitors, including ATR and mTOR inhibitors like torins, completely reversed GCN2 activation in a time-dependent way. Mechanistically, via inhibiting mTORC1-dependent translation, torins increased intracellular leucine, which was sufficient to reverse GCN2 activation and the downstream integrated stress response including stress-induced transcriptional factor ATF4 expression. Strikingly, we found that general translation inhibitors mirrored the effects of torins. Therefore, we propose that mTOR kinase inhibitors concurrently inhibit different branches of amino acid sensing by a dual mechanism involving direct inhibition of mTOR and indirect suppression of GCN2 that are connected by effects on the translation machinery. Collectively, our results highlight distinct ways of regulating GCN2 activity.
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Affiliation(s)
| | | | - Marion Russier
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | | | | | | | | | - Elena Conti
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | - Peter J. Murray
- Max Planck Institute for Biochemistry, Martinsried, Germany,For correspondence: Peter J. Murray
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