1
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Zare A, Salehi S, Bader J, Schneider C, Fischer U, Veh A, Arampatzi P, Mann M, Briese M, Sendtner M. hnRNP R promotes O-GlcNAcylation of eIF4G and facilitates axonal protein synthesis. Nat Commun 2024; 15:7430. [PMID: 39198412 PMCID: PMC11358521 DOI: 10.1038/s41467-024-51678-y] [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: 10/16/2023] [Accepted: 08/12/2024] [Indexed: 09/01/2024] Open
Abstract
Motoneurons critically depend on precise spatial and temporal control of translation for axon growth and the establishment and maintenance of neuromuscular connections. While defects in local translation have been implicated in the pathogenesis of motoneuron disorders, little is known about the mechanisms regulating axonal protein synthesis. Here, we report that motoneurons derived from Hnrnpr knockout mice show reduced axon growth accompanied by lowered synthesis of cytoskeletal and synaptic components in axons. Mutant mice display denervated neuromuscular junctions and impaired motor behavior. In axons, hnRNP R is a component of translation initiation complexes and, through interaction with O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (Ogt), modulates O-GlcNAcylation of eIF4G. Restoring axonal O-GlcNAc levels rescued local protein synthesis and axon growth defects of hnRNP R knockout motoneurons. Together, these findings demonstrate a function of hnRNP R in controlling the local production of key factors required for axon growth and formation of neuromuscular innervations.
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Affiliation(s)
- Abdolhossein Zare
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Saeede Salehi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Jakob Bader
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Cornelius Schneider
- Department of Biochemistry, Theodor Boveri Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Utz Fischer
- Department of Biochemistry, Theodor Boveri Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Alexander Veh
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | | | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
- NNF Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
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2
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Roiuk M, Neff M, Teleman AA. eIF4E-independent translation is largely eIF3d-dependent. Nat Commun 2024; 15:6692. [PMID: 39107322 PMCID: PMC11303786 DOI: 10.1038/s41467-024-51027-z] [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: 09/05/2023] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Translation initiation is a highly regulated step needed for protein synthesis. Most cell-based mechanistic work on translation initiation has been done using non-stressed cells growing in medium with sufficient nutrients and oxygen. This has yielded our current understanding of 'canonical' translation initiation, involving recognition of the mRNA cap by eIF4E1 followed by successive recruitment of initiation factors and the ribosome. Many cells, however, such as tumor cells, are exposed to stresses such as hypoxia, low nutrients or proteotoxic stress. This leads to inactivation of mTORC1 and thereby inactivation of eIF4E1. Hence the question arises how cells translate mRNAs under such stress conditions. We study here how mRNAs are translated in an eIF4E1-independent manner by blocking eIF4E1 using a constitutively active version of eIF4E-binding protein (4E-BP). Via ribosome profiling we identify a subset of mRNAs that are still efficiently translated when eIF4E1 is inactive. We find that these mRNAs preferentially release eIF4E1 when eIF4E1 is inactive and bind instead to eIF3d via its cap-binding pocket. eIF3d then enables these mRNAs to be efficiently translated due to its cap-binding activity. In sum, our work identifies eIF3d-dependent translation as a major mechanism enabling mRNA translation in an eIF4E-independent manner.
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Affiliation(s)
- Mykola Roiuk
- German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Marilena Neff
- German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany.
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany.
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.
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3
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Smirnova AM, Hronová V, Mohammad MP, Herrmannová A, Gunišová S, Petráčková D, Halada P, Coufal Š, Świrski M, Rendleman J, Jendruchová K, Hatzoglou M, Beznosková P, Vogel C, Valášek LS. Stem-loop-induced ribosome queuing in the uORF2/ATF4 overlap fine-tunes stress-induced human ATF4 translational control. Cell Rep 2024; 43:113976. [PMID: 38507410 PMCID: PMC11058473 DOI: 10.1016/j.celrep.2024.113976] [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: 01/10/2024] [Revised: 02/15/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024] Open
Abstract
Activating transcription factor 4 (ATF4) is a master transcriptional regulator of the integrated stress response, leading cells toward adaptation or death. ATF4's induction under stress was thought to be due to delayed translation reinitiation, where the reinitiation-permissive upstream open reading frame 1 (uORF1) plays a key role. Accumulating evidence challenging this mechanism as the sole source of ATF4 translation control prompted us to investigate additional regulatory routes. We identified a highly conserved stem-loop in the uORF2/ATF4 overlap, immediately preceded by a near-cognate CUG, which introduces another layer of regulation in the form of ribosome queuing. These elements explain how the inhibitory uORF2 can be translated under stress, confirming prior observations but contradicting the original regulatory model. We also identified two highly conserved, potentially modified adenines performing antagonistic roles. Finally, we demonstrated that the canonical ATF4 translation start site is substantially leaky scanned. Thus, ATF4's translational control is more complex than originally described, underpinning its key role in diverse biological processes.
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Affiliation(s)
- Anna M Smirnova
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Vladislava Hronová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Mahabub Pasha Mohammad
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Stanislava Gunišová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Denisa Petráčková
- Laboratory of Post-transcriptional Control of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Petr Halada
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Štěpán Coufal
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - Kristína Jendruchová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Christine Vogel
- Department of Biology, New York University, New York, NY, USA.
| | - Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic.
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4
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Brito Querido J, Sokabe M, Díaz-López I, Gordiyenko Y, Fraser CS, Ramakrishnan V. The structure of a human translation initiation complex reveals two independent roles for the helicase eIF4A. Nat Struct Mol Biol 2024; 31:455-464. [PMID: 38287194 PMCID: PMC10948362 DOI: 10.1038/s41594-023-01196-0] [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: 01/10/2023] [Accepted: 11/30/2023] [Indexed: 01/31/2024]
Abstract
Eukaryotic translation initiation involves recruitment of the 43S pre-initiation complex to the 5' end of mRNA by the cap-binding complex eIF4F, forming the 48S translation initiation complex (48S), which then scans along the mRNA until the start codon is recognized. We have previously shown that eIF4F binds near the mRNA exit channel of the 43S, leaving open the question of how mRNA secondary structure is removed as it enters the mRNA channel on the other side of the 40S subunit. Here we report the structure of a human 48S that shows that, in addition to the eIF4A that is part of eIF4F, there is a second eIF4A helicase bound at the mRNA entry site, which could unwind RNA secondary structures as they enter the 48S. The structure also reveals conserved interactions between eIF4F and the 43S, probaby explaining how eIF4F can promote mRNA recruitment in all eukaryotes.
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Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Biological Chemistry and Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
| | | | | | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA.
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5
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Brito Querido J, Díaz-López I, Ramakrishnan V. The molecular basis of translation initiation and its regulation in eukaryotes. Nat Rev Mol Cell Biol 2024; 25:168-186. [PMID: 38052923 DOI: 10.1038/s41580-023-00624-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2023] [Indexed: 12/07/2023]
Abstract
The regulation of gene expression is fundamental for life. Whereas the role of transcriptional regulation of gene expression has been studied for several decades, it has been clear over the past two decades that post-transcriptional regulation of gene expression, of which translation regulation is a major part, can be equally important. Translation can be divided into four main stages: initiation, elongation, termination and ribosome recycling. Translation is controlled mainly during its initiation, a process which culminates in a ribosome positioned with an initiator tRNA over the start codon and, thus, ready to begin elongation of the protein chain. mRNA translation has emerged as a powerful tool for the development of innovative therapies, yet the detailed mechanisms underlying the complex process of initiation remain unclear. Recent studies in yeast and mammals have started to shed light on some previously unclear aspects of this process. In this Review, we discuss the current state of knowledge on eukaryotic translation initiation and its regulation in health and disease. Specifically, we focus on recent advances in understanding the processes involved in assembling the 43S pre-initiation complex and its recruitment by the cap-binding complex eukaryotic translation initiation factor 4F (eIF4F) at the 5' end of mRNA. In addition, we discuss recent insights into ribosome scanning along the 5' untranslated region of mRNA and selection of the start codon, which culminates in joining of the 60S large subunit and formation of the 80S initiation complex.
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Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Irene Díaz-López
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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6
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Shin S, Han MJ, Jedrychowski MP, Zhang Z, Shokat KM, Plas DR, Dephoure N, Yoon SO. mTOR inhibition reprograms cellular proteostasis by regulating eIF3D-mediated selective mRNA translation and promotes cell phenotype switching. Cell Rep 2023; 42:112868. [PMID: 37494188 PMCID: PMC10528759 DOI: 10.1016/j.celrep.2023.112868] [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: 12/05/2022] [Revised: 05/31/2023] [Accepted: 07/11/2023] [Indexed: 07/28/2023] Open
Abstract
Cells maintain and dynamically change their proteomes according to the environment and their needs. Mechanistic target of rapamycin (mTOR) is a key regulator of proteostasis, homeostasis of the proteome. Thus, dysregulation of mTOR leads to changes in proteostasis and the consequent progression of diseases, including cancer. Based on the physiological and clinical importance of mTOR signaling, we investigated mTOR feedback signaling, proteostasis, and cell fate. Here, we reveal that mTOR targeting inhibits eIF4E-mediated cap-dependent translation, but feedback signaling activates a translation initiation factor, eukaryotic translation initiation factor 3D (eIF3D), to sustain alternative non-canonical translation mechanisms. Importantly, eIF3D-mediated protein synthesis enables cell phenotype switching from proliferative to more migratory. eIF3D cooperates with mRNA-binding proteins such as heterogeneous nuclear ribonucleoprotein F (hnRNPF), heterogeneous nuclear ribonucleoprotein K (hnRNPK), and Sjogren syndrome antigen B (SSB) to support selective mRNA translation following mTOR inhibition, which upregulates and activates proteins involved in insulin receptor (INSR)/insulin-like growth factor 1 receptor (IGF1R)/insulin receptor substrate (IRS) and interleukin 6 signal transducer (IL-6ST)/Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling. Our study highlights the mechanisms by which cells establish the dynamic change of proteostasis and the resulting phenotype switch.
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Affiliation(s)
- Sejeong Shin
- Department of Physiology and Biophysics, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, USA
| | - Min-Joon Han
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | - Ziyang Zhang
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Kevan M Shokat
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Noah Dephoure
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10021, USA
| | - Sang-Oh Yoon
- Department of Physiology and Biophysics, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, USA.
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7
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She R, Luo J, Weissman JS. Translational fidelity screens in mammalian cells reveal eIF3 and eIF4G2 as regulators of start codon selectivity. Nucleic Acids Res 2023; 51:6355-6369. [PMID: 37144468 PMCID: PMC10325891 DOI: 10.1093/nar/gkad329] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 04/13/2023] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
The translation initiation machinery and the ribosome orchestrate a highly dynamic scanning process to distinguish proper start codons from surrounding nucleotide sequences. Here, we performed genome-wide CRISPRi screens in human K562 cells to systematically identify modulators of the frequency of translation initiation at near-cognate start codons. We observed that depletion of any eIF3 core subunit promoted near-cognate start codon usage, though sensitivity thresholds of each subunit to sgRNA-mediated depletion varied considerably. Double sgRNA depletion experiments suggested that enhanced near-cognate usage in eIF3D depleted cells required canonical eIF4E cap-binding and was not driven by eIF2A or eIF2D-dependent leucine tRNA initiation. We further characterized the effects of eIF3D depletion and found that the N-terminus of eIF3D was strictly required for accurate start codon selection, whereas disruption of the cap-binding properties of eIF3D had no effect. Lastly, depletion of eIF3D activated TNFα signaling via NF-κB and the interferon gamma response. Similar transcriptional profiles were observed upon knockdown of eIF1A and eIF4G2, which also promoted near-cognate start codon usage, suggesting that enhanced near-cognate usage could potentially contribute to NF-κB activation. Our study thus provides new avenues to study the mechanisms and consequences of alternative start codon usage.
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Affiliation(s)
- Richard She
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Jingchuan Luo
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Jonathan S Weissman
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology; Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
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8
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Duan H, Zhang S, Zarai Y, Öllinger R, Wu Y, Sun L, Hu C, He Y, Tian G, Rad R, Kong X, Cheng Y, Tuller T, Wolf DA. eIF3 mRNA selectivity profiling reveals eIF3k as a cancer-relevant regulator of ribosome content. EMBO J 2023:e112362. [PMID: 37155573 DOI: 10.15252/embj.2022112362] [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: 08/16/2022] [Revised: 03/04/2023] [Accepted: 04/20/2023] [Indexed: 05/10/2023] Open
Abstract
eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA-selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo-complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5'-UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k-l as a mRNA-specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress.
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Affiliation(s)
- Haoran Duan
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Siqiong Zhang
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Yoram Zarai
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Rupert Öllinger
- Institute of Molecular Oncology and Functional Genomics and Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Yanmeng Wu
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Li Sun
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Cheng Hu
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Yaohui He
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Guiyou Tian
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Roland Rad
- Institute of Molecular Oncology and Functional Genomics and Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Xiangquan Kong
- Department of Radiation Oncology, Xiamen Humanity Hospital, Fujian Medical University, Xiamen, China
| | - Yabin Cheng
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Tamir Tuller
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
- The Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Dieter A Wolf
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
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9
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Zhang D, Zhu L, Wang F, Li P, Wang Y, Gao Y. Molecular mechanisms of eukaryotic translation fidelity and their associations with diseases. Int J Biol Macromol 2023; 242:124680. [PMID: 37141965 DOI: 10.1016/j.ijbiomac.2023.124680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 04/27/2023] [Indexed: 05/06/2023]
Abstract
Converting genetic information into functional proteins is a complex, multi-step process, with each step being tightly regulated to ensure the accuracy of translation, which is critical to cellular health. In recent years, advances in modern biotechnology, especially the development of cryo-electron microscopy and single-molecule techniques, have enabled a clearer understanding of the mechanisms of protein translation fidelity. Although there are many studies on the regulation of protein translation in prokaryotes, and the basic elements of translation are highly conserved in prokaryotes and eukaryotes, there are still great differences in the specific regulatory mechanisms. This review describes how eukaryotic ribosomes and translation factors regulate protein translation and ensure translation accuracy. However, a certain frequency of translation errors does occur in translation, so we describe diseases that arise when the rate of translation errors reaches or exceeds a threshold of cellular tolerance.
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Affiliation(s)
- Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lei Zhu
- College of Basic Medical, Qingdao Binhai University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
| | - Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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10
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Song Z, Lin J, Su R, Ji Y, Jia R, Li S, Shan G, Huang C. eIF3j inhibits translation of a subset of circular RNAs in eukaryotic cells. Nucleic Acids Res 2022; 50:11529-11549. [PMID: 36330957 PMCID: PMC9723666 DOI: 10.1093/nar/gkac980] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/04/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Increasing studies have revealed that a subset of circular RNAs (circRNAs) harbor an open reading frame and can act as protein-coding templates to generate functional proteins that are closely associated with multiple physiological and disease-relevant processes, and thus proper regulation of synthesis of these circRNA-derived proteins is a fundamental cellular process required for homeostasis maintenance. However, how circRNA translation initiation is coordinated by different trans-acting factors remains poorly understood. In particular, the impact of different eukaryotic translation initiation factors (eIFs) on circRNA translation and the physiological relevance of this distinct regulation have not yet been characterized. In this study, we screened all 43 Drosophila eIFs and revealed the conflicting functions of eIF3 subunits in the translational control of the translatable circRNA circSfl: eIF3 is indispensable for circSfl translation, while the eIF3-associated factor eIF3j is the most potent inhibitor. Mechanistically, the binding of eIF3j to circSfl promotes the disassociation of eIF3. The C-terminus of eIF3j and an RNA regulon within the circSfl untranslated region (UTR) are essential for the inhibitory effect of eIF3j. Moreover, we revealed the physiological relevance of eIF3j-mediated circSfl translation repression in response to heat shock. Finally, additional translatable circRNAs were identified to be similarly regulated in an eIF3j-dependent manner. Altogether, our study provides a significant insight into the field of cap-independent translational regulation and undiscovered functions of eIF3.
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Affiliation(s)
| | | | - Rui Su
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Yu Ji
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Ruirui Jia
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Shi Li
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Ge Shan
- School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Chuan Huang
- To whom correspondence should be addressed. Tel: +86 19956025374;
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11
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Zhong X, Ji C, Ren D, Ke A, Yang Z. Circular RNA circEIF3C promotes intrahepatic cholangiocarcinoma progression and immune evasion via the miR-34a-5p/B7–H4 axis. Genes Dis 2022; 10:370-372. [DOI: 10.1016/j.gendis.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/28/2022] [Accepted: 05/01/2022] [Indexed: 11/30/2022] Open
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12
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Cabrera-Orefice A, Potter A, Evers F, Hevler JF, Guerrero-Castillo S. Complexome Profiling-Exploring Mitochondrial Protein Complexes in Health and Disease. Front Cell Dev Biol 2022; 9:796128. [PMID: 35096826 PMCID: PMC8790184 DOI: 10.3389/fcell.2021.796128] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/08/2021] [Indexed: 12/14/2022] Open
Abstract
Complexome profiling (CP) is a state-of-the-art approach that combines separation of native proteins by electrophoresis, size exclusion chromatography or density gradient centrifugation with tandem mass spectrometry identification and quantification. Resulting data are computationally clustered to visualize the inventory, abundance and arrangement of multiprotein complexes in a biological sample. Since its formal introduction a decade ago, this method has been mostly applied to explore not only the composition and abundance of mitochondrial oxidative phosphorylation (OXPHOS) complexes in several species but also to identify novel protein interactors involved in their assembly, maintenance and functions. Besides, complexome profiling has been utilized to study the dynamics of OXPHOS complexes, as well as the impact of an increasing number of mutations leading to mitochondrial disorders or rearrangements of the whole mitochondrial complexome. Here, we summarize the major findings obtained by this approach; emphasize its advantages and current limitations; discuss multiple examples on how this tool could be applied to further investigate pathophysiological mechanisms and comment on the latest advances and opportunity areas to keep developing this methodology.
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Affiliation(s)
- Alfredo Cabrera-Orefice
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alisa Potter
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Felix Evers
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Johannes F Hevler
- Biomolecular Mass Spectrometry and Proteomics, University of Utrecht, Utrecht, Netherlands.,Bijvoet Center for Biomolecular Research, University of Utrecht, Utrecht, Netherlands.,Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, Netherlands.,Netherlands Proteomics Center, Utrecht, Netherlands
| | - Sergio Guerrero-Castillo
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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13
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Liu X, Moshiri H, He Q, Sahoo A, Walker SE. Deletion of the N-Terminal Domain of Yeast Eukaryotic Initiation Factor 4B Reprograms Translation and Reduces Growth in Urea. Front Mol Biosci 2022; 8:787781. [PMID: 35047555 PMCID: PMC8762332 DOI: 10.3389/fmolb.2021.787781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/03/2021] [Indexed: 11/24/2022] Open
Abstract
The yeast eukaryotic initiation factor 4B binds the 40S subunit in translation preinitiation complexes (PICs), promoting mRNA recruitment. Recent evidence indicates yeast mRNAs have variable dependence on eIF4B under optimal growth conditions. Given the ability of eIF4B to promote translation as a function of nutrient conditions in mammalian cells, we wondered if eIF4B activities in translation could alter phenotypes in yeast through differential mRNA selection for translation. Here we compared the effects of disrupting yeast eIF4B RNA- and 40S-binding motifs under ∼1400 growth conditions. The RNA-Recognition Motif (RRM) was dispensable for stress responses, but the 40S-binding N-terminal Domain (NTD) promoted growth in response to stressors requiring robust cellular integrity. In particular, the NTD conferred a strong growth advantage in the presence of urea, which may be important for pathogenesis of related fungal species. Ribosome profiling indicated that similar to complete eIF4B deletion, deletion of the NTD dramatically reduced translation, particularly of those mRNAs with long and highly structured 5-prime untranslated regions. This behavior was observed both with and without urea exposure, but the specific mRNA pool associated with ribosomes in response to urea differed. Deletion of the NTD led to relative increases in ribosome association of shorter transcripts with higher dependence on eIF4G, as was noted previously for eIF4B deletion. Gene ontology analysis indicated that proteins encoded by eIF4B NTD-dependent transcripts were associated with the cellular membrane system and the cell wall, while NTD-independent transcripts encoded proteins associated with cytoplasmic proteins and protein synthesis. This analysis highlighted the difference in structure content of mRNAs encoding membrane versus cytoplasmic housekeeping proteins and the variable reliance of specific gene ontology classes on various initiation factors promoting otherwise similar functions. Together our analyses suggest that deletion of the eIF4B NTD prevents cellular stress responses by affecting the capacity to translate a diverse mRNA pool.
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Affiliation(s)
- Xiaozhuo Liu
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Houtan Moshiri
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Qian He
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Ansuman Sahoo
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Sarah E Walker
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
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14
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Fujii K, Zhulyn O, Byeon GW, Genuth NR, Kerr CH, Walsh EM, Barna M. Controlling tissue patterning by translational regulation of signaling transcripts through the core translation factor eIF3c. Dev Cell 2021; 56:2928-2937.e9. [PMID: 34752747 DOI: 10.1016/j.devcel.2021.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/06/2021] [Accepted: 10/12/2021] [Indexed: 12/13/2022]
Abstract
Although gene expression is tightly regulated during embryonic development, the impact of translational control has received less experimental attention. Here, we find that eukaryotic translation initiation factor-3 (eIF3) is required for Shh-mediated tissue patterning. Analysis of loss-of-function eIF3 subunit c (Eif3c) mice reveal a unique sensitivity to the Shh receptor patched 1 (Ptch1) dosage. Genome-wide in vivo enhanced cross-linking immunoprecipitation sequence (eCLIP-seq) shows unexpected specificity for eIF3 binding to a pyrimidine-rich motif present in subsets of 5'-UTRs and a corresponding change in the translation of these transcripts by ribosome profiling in Eif3c loss-of-function embryos. We further find a transcript specific effect in Eif3c loss-of-function embryos whereby translation of Ptch1 through this pyrimidine-rich motif is specifically sensitive to eIF3 amount. Altogether, this work uncovers hidden specificity of housekeeping translation initiation machinery for the translation of key developmental signaling transcripts.
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Affiliation(s)
- Kotaro Fujii
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Center for Neurogenetics, University of Florida, Gainesville, FL 32610, USA; Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA.
| | - Olena Zhulyn
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Gun Woo Byeon
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Electrical and Computer Engineering, University of Washington, Seattle, WA 98195, USA
| | - Naomi R Genuth
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Craig H Kerr
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Erin M Walsh
- Center for Neurogenetics, University of Florida, Gainesville, FL 32610, USA; Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Maria Barna
- Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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15
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Egorova T, Biziaev N, Shuvalov A, Sokolova E, Mukba S, Evmenov K, Zotova M, Kushchenko A, Shuvalova E, Alkalaeva E. eIF3j facilitates loading of release factors into the ribosome. Nucleic Acids Res 2021; 49:11181-11196. [PMID: 34591963 PMCID: PMC8565342 DOI: 10.1093/nar/gkab854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/23/2021] [Accepted: 09/14/2021] [Indexed: 12/14/2022] Open
Abstract
eIF3j is one of the eukaryotic translation factors originally reported as the labile subunit of the eukaryotic translation initiation factor eIF3. The yeast homolog of this protein, Hcr1, has been implicated in stringent AUG recognition as well as in controlling translation termination and stop codon readthrough. Using a reconstituted mammalian in vitro translation system, we showed that the human protein eIF3j is also important for translation termination. We showed that eIF3j stimulates peptidyl-tRNA hydrolysis induced by a complex of eukaryotic release factors, eRF1-eRF3. Moreover, in combination with the initiation factor eIF3, which also stimulates peptide release, eIF3j activity in translation termination increases. We found that eIF3j interacts with the pre-termination ribosomal complex, and eRF3 destabilises this interaction. In the solution, these proteins bind to each other and to other participants of translation termination, eRF1 and PABP, in the presence of GTP. Using a toe-printing assay, we determined the stage at which eIF3j functions – binding of release factors to the A-site of the ribosome before GTP hydrolysis. Based on these data, we assumed that human eIF3j is involved in the regulation of translation termination by loading release factors into the ribosome.
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Affiliation(s)
- Tatiana Egorova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, 119991 Moscow, Russia
| | - Nikita Biziaev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexey Shuvalov
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, 119991 Moscow, Russia
| | - Elizaveta Sokolova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, 119991 Moscow, Russia
| | - Sabina Mukba
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Konstantin Evmenov
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maria Zotova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Artem Kushchenko
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Ekaterina Shuvalova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, 119991 Moscow, Russia
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16
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de Breyne S, Vindry C, Guillin O, Condé L, Mure F, Gruffat H, Chavatte L, Ohlmann T. Translational control of coronaviruses. Nucleic Acids Res 2020; 48:12502-12522. [PMID: 33264393 PMCID: PMC7736815 DOI: 10.1093/nar/gkaa1116] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 12/14/2022] Open
Abstract
Coronaviruses represent a large family of enveloped RNA viruses that infect a large spectrum of animals. In humans, the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is responsible for the current COVID-19 pandemic and is genetically related to SARS-CoV and Middle East respiratory syndrome-related coronavirus (MERS-CoV), which caused outbreaks in 2002 and 2012, respectively. All viruses described to date entirely rely on the protein synthesis machinery of the host cells to produce proteins required for their replication and spread. As such, virus often need to control the cellular translational apparatus to avoid the first line of the cellular defense intended to limit the viral propagation. Thus, coronaviruses have developed remarkable strategies to hijack the host translational machinery in order to favor viral protein production. In this review, we will describe some of these strategies and will highlight the role of viral proteins and RNAs in this process.
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Affiliation(s)
- Sylvain de Breyne
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Caroline Vindry
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Olivia Guillin
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Lionel Condé
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Fabrice Mure
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Henri Gruffat
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Laurent Chavatte
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Théophile Ohlmann
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
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17
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Structural Differences in Translation Initiation between Pathogenic Trypanosomatids and Their Mammalian Hosts. Cell Rep 2020; 33:108534. [PMID: 33357443 PMCID: PMC7773551 DOI: 10.1016/j.celrep.2020.108534] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 10/08/2020] [Accepted: 11/25/2020] [Indexed: 11/25/2022] Open
Abstract
Canonical mRNA translation in eukaryotes begins with the formation of the 43S pre-initiation complex (PIC). Its assembly requires binding of initiator Met-tRNAiMet and several eukaryotic initiation factors (eIFs) to the small ribosomal subunit (40S). Compared to their mammalian hosts, trypanosomatids present significant structural differences in their 40S, suggesting substantial variability in translation initiation. Here, we determine the structure of the 43S PIC from Trypanosoma cruzi, the parasite causing Chagas disease. Our structure shows numerous specific features, such as the variant eIF3 structure and its unique interactions with the large rRNA expansion segments (ESs) 9S, 7S, and 6S, and the association of a kinetoplastid-specific DDX60-like helicase. It also reveals the 40S-binding site of the eIF5 C-terminal domain and structures of key terminal tails of several conserved eIFs underlying their activities within the PIC. Our results are corroborated by glutathione S-transferase (GST) pull-down assays in both human and T. cruzi and mass spectrometry data. Structure of the 43S pre-initiation complex from Trypanosoma cruzi is solved at 3.33 Å The kinetoplastids’ eIF3 core is a septamer that binds mainly the unique, extended ES7s A kinetoplastid-specific DDX60-like helicase binds to the 43S PIC entry pore The 40S positions of eIF5-CTD and key tails of several eIFs are determined
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18
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Booy EP, Gussakovsky D, Choi T, McKenna SA. The noncoding RNA BC200 associates with polysomes to positively regulate mRNA translation in tumor cells. J Biol Chem 2020; 296:100036. [PMID: 33410401 PMCID: PMC7949042 DOI: 10.1074/jbc.ra120.015775] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 12/19/2022] Open
Abstract
BC200 is a noncoding RNA elevated in a broad spectrum of tumor cells that is critical for cell viability, invasion, and migration. Overexpression studies have implicated BC200 and the rodent analog BC1 as negative regulators of translation in both cell-based and in vitro translation assays. Although these studies are consistent, they have not been confirmed in knockdown studies and direct evidence for this function is lacking. Herein, we have demonstrated that BC200 knockdown is correlated with a decrease in global translation rates. As this conflicts with the hypothesis that BC200 is a translational suppressor, we overexpressed BC200 by transfection of in vitro transcribed RNA and transient expression from transfected plasmids. In this context BC200 suppressed translation; however, an innate immune response confounded the data. To overcome this, breast cancer cells stably overexpressing BC200 and various control RNAs were developed by selection for genomic incorporation of a plasmid coexpressing BC200 and the neomycin resistance gene. Stable overexpression of BC200 was associated with elevated translation levels in pooled stable cell lines and isolated single-cell clones. Cross-linking sucrose density gradient centrifugation demonstrated an association of BC200 and its reported binding partners SRP9/14, CSDE1, DHX36, and PABPC1 with both ribosomal subunits and polysomal RNA, an association not previously observed owing to the labile nature of the interactions. In summary, these data present a novel understanding of BC200 function as well as optimized methodology that has far reaching implications in the study of noncoding RNAs, particularly within the context of translational regulatory mechanisms.
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Affiliation(s)
- Evan P Booy
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Daniel Gussakovsky
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Taegi Choi
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sean A McKenna
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
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19
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Hernández G, García A, Sonenberg N, Lasko P. Unorthodox Mechanisms to Initiate Translation Open Novel Paths for Gene Expression. J Mol Biol 2020; 432:166702. [PMID: 33166539 DOI: 10.1016/j.jmb.2020.10.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/24/2022]
Abstract
Translation in eukaryotes is dependent on the activity of translation initiation factor (eIF) 4G family of proteins, a scaffold protein that, during the initiation step, coordinates the activity of other eIFs to recruit the 40S ribosomal subunit to the mRNA. Three decades of research on protein synthesis and its regulation has provided a wealth of evidence supporting the crucial role of cap-dependent translation initiation, which involves eIF4G. However, the recent discovery of a surprising variety of alternative mechanisms to initiate translation in the absence of eIF4G has stirred the orthodox view of how protein synthesis is performed. These mechanisms involve novel interactions among known eIFs, or between known eIFs and other proteins not previously linked to translation. Thus, a new picture is emerging in which the unorthodox translation initiation complexes contribute to the diversity of mechanisms that regulate gene expression in eukaryotes.
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Affiliation(s)
- Greco Hernández
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, 14080 Mexico City, Mexico.
| | - Alejandra García
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, 14080 Mexico City, Mexico
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Paul Lasko
- Department of Biology, McGill University, Montreal, Québec, Canada; Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
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20
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Wolf DA, Lin Y, Duan H, Cheng Y. eIF-Three to Tango: emerging functions of translation initiation factor eIF3 in protein synthesis and disease. J Mol Cell Biol 2020; 12:403-409. [PMID: 32279082 PMCID: PMC7333474 DOI: 10.1093/jmcb/mjaa018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/20/2020] [Accepted: 02/17/2020] [Indexed: 12/12/2022] Open
Abstract
Studies over the past three years have substantially expanded the involvements of eukaryotic initiation factor 3 (eIF3) in messenger RNA (mRNA) translation. It now appears that this multi-subunit complex is involved in every possible form of mRNA translation, controlling every step of protein synthesis from initiation to elongation, termination, and quality control in positive as well as negative fashion. Through the study of eIF3, we are beginning to appreciate protein synthesis as a highly integrated process coordinating protein production with protein folding, subcellular targeting, and degradation. At the same time, eIF3 subunits appear to have specific functions that probably vary between different tissues and individual cells. Considering the broad functions of eIF3 in protein homeostasis, it comes as little surprise that eIF3 is increasingly implicated in major human diseases and first attempts at therapeutically targeting eIF3 have been undertaken. Much remains to be learned, however, about subunit- and tissue-specific functions of eIF3 in protein synthesis and disease and their regulation by environmental conditions and post-translational modifications.
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Affiliation(s)
- Dieter A Wolf
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research & Innovation Center for Cell Stress Signaling, Xiamen University, Xiamen 361102, China
| | - Yingying Lin
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research & Innovation Center for Cell Stress Signaling, Xiamen University, Xiamen 361102, China
| | - Haoran Duan
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research & Innovation Center for Cell Stress Signaling, Xiamen University, Xiamen 361102, China
| | - Yabin Cheng
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research & Innovation Center for Cell Stress Signaling, Xiamen University, Xiamen 361102, China
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