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Choi JH, Luo J, Hesketh GG, Guo S, Pistofidis A, Ladak RJ, An Y, Naeli P, Alain T, Schmeing TM, Gingras AC, Duchaine T, Zhang X, Sonenberg N, Jafarnejad SM. Repression of mRNA translation initiation by GIGYF1 via disrupting the eIF3-eIF4G1 interaction. SCIENCE ADVANCES 2024; 10:eadl5638. [PMID: 39018414 PMCID: PMC466957 DOI: 10.1126/sciadv.adl5638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 06/13/2024] [Indexed: 07/19/2024]
Abstract
Viruses can selectively repress the translation of mRNAs involved in the antiviral response. RNA viruses exploit the Grb10-interacting GYF (glycine-tyrosine-phenylalanine) proteins 2 (GIGYF2) and eukaryotic translation initiation factor 4E (eIF4E) homologous protein 4EHP to selectively repress the translation of transcripts such as Ifnb1, which encodes the antiviral cytokine interferon-β (IFN-β). Herein, we reveal that GIGYF1, a paralog of GIGYF2, robustly represses cellular mRNA translation through a distinct 4EHP-independent mechanism. Upon recruitment to a target mRNA, GIGYF1 binds to subunits of eukaryotic translation initiation factor 3 (eIF3) at the eIF3-eIF4G1 interaction interface. This interaction disrupts the eIF3 binding to eIF4G1, resulting in transcript-specific translational repression. Depletion of GIGYF1 induces a robust immune response by derepressing IFN-β production. Our study highlights a unique mechanism of translational regulation by GIGYF1 that involves sequestering eIF3 and abrogating its binding to eIF4G1. This mechanism has profound implications for the host response to viral infections.
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Affiliation(s)
- Jung-Hyun Choi
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Jun Luo
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Geoffrey G. Hesketh
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Shuyue Guo
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Angelos Pistofidis
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Reese Jalal Ladak
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Yuxin An
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Parisa Naeli
- Patrick G. Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast BT9 7AE, UK
| | - Tommy Alain
- Department of Biochemistry, Microbiology and Immunology, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - T. Martin Schmeing
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Anne-Claude Gingras
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Thomas Duchaine
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Xu Zhang
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Nahum Sonenberg
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada
| | - Seyed Mehdi Jafarnejad
- Patrick G. Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast BT9 7AE, UK
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2
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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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3
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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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4
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Bose P, Baron N, Pullaiahgari D, Ben-Zvi A, Shapira M. LeishIF3d is a non-canonical cap-binding protein in Leishmania. Front Mol Biosci 2023; 10:1191934. [PMID: 37325473 PMCID: PMC10266417 DOI: 10.3389/fmolb.2023.1191934] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
Translation of most cellular mRNAs in eukaryotes proceeds through a cap-dependent pathway, whereby the cap-binding complex, eIF4F, anchors the pre-initiation complex at the 5' end of mRNAs driving translation initiation. The genome of Leishmania encodes a large repertoire of cap-binding complexes that fulfill a variety of functions possibly involved in survival along the life cycle. However, most of these complexes function in the promastigote life form that resides in the sand fly vector and decrease their activity in amastigotes, the mammalian life form. Here we examined the possibility that LeishIF3d drives translation in Leishmania using alternative pathways. We describe a non-canonical cap-binding activity of LeishIF3d and examine its potential role in driving translation. LeishIF3d is required for translation, as reducing its expression by a hemizygous deletion reduces the translation activity of the LeishIF3d(+/-) mutant cells. Proteomic analysis of the mutant cells highlights the reduced expression of flagellar and cytoskeletal proteins, as reflected in the morphological changes observed in the mutant cells. Targeted mutations in two predicted alpha helices diminish the cap-binding activity of LeishIF3d. Overall, LeishIF3d could serve as a driving force for alternative translation pathways, although it does not seem to offer an alternative pathway for translation in amastigotes.
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Affiliation(s)
- Priyanka Bose
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Nofar Baron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | | | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michal Shapira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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5
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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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6
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Ma S, Liu JY, Zhang JT. eIF3d: A driver of noncanonical cap-dependent translation of specific mRNAs and a trigger of biological/pathological processes. J Biol Chem 2023; 299:104658. [PMID: 36997088 PMCID: PMC10165153 DOI: 10.1016/j.jbc.2023.104658] [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: 09/01/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 03/31/2023] Open
Abstract
Eukaryotic initiation factor 3d (eIF3d), a known RNA-binding subunit of the eIF3 complex, is a 66 to 68-kDa protein with an RNA-binding motif and a cap-binding domain. Compared with other eIF3 subunits, eIF3d is relatively understudied. However, recent progress in studying eIF3d has revealed a number of intriguing findings on its role in maintaining eIF3 complex integrity, global protein synthesis, and in biological and pathological processes. It has also been reported that eIF3d has noncanonical functions in regulating translation of a subset of mRNAs by binding to 5'-UTRs or interacting with other proteins independent of the eIF3 complex and additional functions in regulating protein stability. The noncanonical regulation of mRNA translation or protein stability may contribute to the role of eIF3d in biological processes such as metabolic stress adaptation and in disease onset and progression including severe acute respiratory syndrome coronavirus 2 infection, tumorigenesis, and acquired immune deficiency syndrome. In this review, we critically evaluate the recent studies on these aspects of eIF3d and assess prospects in understanding the function of eIF3d in regulating protein synthesis and in biological and pathological processes.
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Affiliation(s)
- Shijie Ma
- Department of Cell and Cancer Biology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Jing-Yuan Liu
- Department of Medicine, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Jian-Ting Zhang
- Department of Cell and Cancer Biology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
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7
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Mendoza SV, Genetos DC, Yellowley CE. Hypoxia-Inducible Factor-2α Signaling in the Skeletal System. JBMR Plus 2023; 7:e10733. [PMID: 37065626 PMCID: PMC10097641 DOI: 10.1002/jbm4.10733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/13/2023] Open
Abstract
Hypoxia-inducible factors (HIFs) are oxygen-dependent heterodimeric transcription factors that mediate molecular responses to reductions in cellular oxygen (hypoxia). HIF signaling involves stable HIF-β subunits and labile, oxygen-sensitive HIF-α subunits. Under hypoxic conditions, the HIF-α subunit is stabilized, complexes with nucleus-confined HIF-β subunit, and transcriptionally regulates hypoxia-adaptive genes. Transcriptional responses to hypoxia include altered energy metabolism, angiogenesis, erythropoiesis, and cell fate. Three isoforms of HIF-α-HIF-1α, HIF-2α, and HIF-3α-are found in diverse cell types. HIF-1α and HIF-2α serve as transcriptional activators, whereas HIF-3α restricts HIF-1α and HIF-2α. The structure and isoform-specific functions of HIF-1α in mediating molecular responses to hypoxia are well established across a wide range of cell and tissue types. The contributions of HIF-2α to hypoxic adaptation are often unconsidered if not outrightly attributed to HIF-1α. This review establishes what is currently known about the diverse roles of HIF-2α in mediating the hypoxic response in skeletal tissues, with specific focus on development and maintenance of skeletal fitness. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Sarah V Mendoza
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
| | - Damian C Genetos
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
| | - Clare E Yellowley
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
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8
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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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9
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Pimkova K, Jassinskaja M, Munita R, Ciesla M, Guzzi N, Cao Thi Ngoc P, Vajrychova M, Johansson E, Bellodi C, Hansson J. Quantitative analysis of redox proteome reveals oxidation-sensitive protein thiols acting in fundamental processes of developmental hematopoiesis. Redox Biol 2022; 53:102343. [PMID: 35640380 PMCID: PMC9157258 DOI: 10.1016/j.redox.2022.102343] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 11/22/2022] Open
Abstract
Fetal and adult hematopoietic stem and progenitor cells (HSPCs) are characterized by distinct redox homeostasis that may influence their differential cellular behavior in normal and malignant hematopoiesis. In this work, we have applied a quantitative mass spectrometry-based redox proteomic approach to comprehensively describe reversible cysteine modifications in primary mouse fetal and adult HSPCs. We defined the redox state of 4,438 cysteines in fetal and adult HSPCs and demonstrated a higher susceptibility to oxidation of protein thiols in fetal HSPCs. Our data identified ontogenic changes to oxidation state of thiols in proteins with a pronounced role in metabolism and protein homeostasis. Additional redox proteomic analysis identified oxidation changes to thiols acting in mitochondrial respiration as well as protein homeostasis to be triggered during onset of MLL-ENL leukemogenesis in fetal HSPCs. Our data has demonstrated that redox signaling contributes to the regulation of fundamental processes of developmental hematopoiesis and has pinpointed potential targetable redox-sensitive proteins in in utero-initiated MLL-rearranged leukemia.
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Affiliation(s)
- K Pimkova
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden; BIOCEV, 1st Medical Faculty, Charles University, Vestec, Czech Republic.
| | - M Jassinskaja
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - R Munita
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - M Ciesla
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - N Guzzi
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - P Cao Thi Ngoc
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - M Vajrychova
- Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - E Johansson
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - C Bellodi
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden
| | - J Hansson
- Lund Stem Cell Center, Division of Molecular Hematology, Lund University, Lund, Sweden.
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10
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Wu M, Han Y, Gong X, Wan K, Liu Y, Zhou Y, Zhang L, Tang G, Fang H, Chen B, Yang F, Zhao Q, Wang G, Zhanghuang C, Zhang Y. Novel Insight of CircRNAs in Cervical Cancer: Potential Biomarkers and Therapeutic Target. Front Med (Lausanne) 2022; 9:759928. [PMID: 35814779 PMCID: PMC9260044 DOI: 10.3389/fmed.2022.759928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 03/23/2022] [Indexed: 01/01/2023] Open
Abstract
Cervical cancer (CC) is a prominent cancer around the globe, with a high incidence, and fatality rate. Numerous recent investigations have shown that various non-coding RNAs are associated with the progression of CC. Circular RNAs, a novel class of non-coding RNAs, have a single chain covalent closed-loop structure and are involved in cell growth and other physiological processes. These dysregulated circRNAs seem to have environment-specific functions. They have been demonstrated in certain studies to have a dual involvement in oncogene production and tumor inhibition in different cell settings. Simultaneously, some evidence indicates that circRNAs are abnormally expressed in CC and contributes to its progression. Thus, the distinctive expression profile of circRNAs is associated with the diagnosis, prognosis, and treatment outcomes of CC. We summarized numerous CC-specific circles and their function in revealing the molecular processes of carcinogenesis and progression in CC in this review. Taken together, these data suggest that circRNA may be used as an early detection biomarker and potential therapeutic target in patients with CC.
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Affiliation(s)
- Maomao Wu
- Department of Pharmacy, Anhui Chest Hospital, Hefei, China
| | - Yanxun Han
- Department of Otolaryngology – Head and Neck Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | | | - Ke Wan
- School of Pharmacy, Anhui Medical University, Hefei, China
| | - Yuchen Liu
- Department of Otolaryngology – Head and Neck Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yi Zhou
- The First Clinical Medical College, Anhui Medical University, Hefei, China
| | - Lizhi Zhang
- The First Clinical Medical College, Anhui Medical University, Hefei, China
| | - Guozheng Tang
- The First Clinical Medical College, Anhui Medical University, Hefei, China
| | - Hui Fang
- Department of Pharmacy, Hangzhou Normal University Affiliated Hospital, Hangzhou, China
| | - Bangjie Chen
- The First Clinical Medical College, Anhui Medical University, Hefei, China
| | - Fan Yang
- The First Clinical Medical College, Anhui Medical University, Hefei, China
| | - Qing Zhao
- Department of Pharmacy, Hangzhou Normal University Affiliated Hospital, Hangzhou, China
| | - Genbao Wang
- Department of Pharmacy, Hangzhou Normal University Affiliated Hospital, Hangzhou, China
- Genbao Wang,
| | - Chenghao Zhanghuang
- Department of Urology, Kunming Children’s Hospital, Kunming, China
- *Correspondence: Chenghao Zhanghuang,
| | - Yunling Zhang
- Department of Pharmacy, Anhui Chest Hospital, Hefei, China
- Yunling Zhang,
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11
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Ma S, Dong Z, Huang Y, Liu JY, Zhang JT. Translation initiation factor eIF3a regulates glucose metabolism and cell proliferation via promoting small GTPase Rheb synthesis and AMPK activation. J Biol Chem 2022; 298:102044. [PMID: 35595099 PMCID: PMC9207673 DOI: 10.1016/j.jbc.2022.102044] [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: 02/05/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 12/05/2022] Open
Abstract
Eukaryotic translation initiation factor 3 subunit A (eIF3a), the largest subunit of the eIF3 complex, has been shown to be overexpressed in malignant cancer cells, potentially making it a proto-oncogene. eIF3a overexpression can drive cancer cell proliferation but contributes to better prognosis. While its contribution to prognosis was previously shown to be due to its function in suppressing synthesis of DNA damage repair proteins, it remains unclear how eIF3a regulates cancer cell proliferation. In this study, we show using genetic approaches that eIF3a controls cell proliferation by regulating glucose metabolism via the phosphorylation and activation of AMP-activated protein kinase alpha (AMPKα) at Thr172 in its kinase activation loop. We demonstrate that eIF3a regulates AMPK activation mainly by controlling synthesis of the small GTPase Rheb, largely independent of the well-known AMPK upstream liver kinase B1 and Ca2+/calmodulin-dependent protein kinase kinase 2, and also independent of mammalian target of rapamycin signaling and glucose levels. Our findings suggest that glucose metabolism in and proliferation of cancer cells may be translationally regulated via a novel eIF3a–Rheb–AMPK signaling axis.
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Affiliation(s)
- Shijie Ma
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Zizheng Dong
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Yanfei Huang
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Jing-Yuan Liu
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Jian-Ting Zhang
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
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12
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eIF3a regulation of mTOR signaling and translational control via HuR in cellular response to DNA damage. Oncogene 2022; 41:2431-2443. [PMID: 35279705 PMCID: PMC9035104 DOI: 10.1038/s41388-022-02262-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/16/2022] [Accepted: 02/23/2022] [Indexed: 01/29/2023]
Abstract
eIF3a (eukaryotic translation initiation factor 3a), a subunit of the eIF3 complex, has been suggested to play a regulatory role in protein synthesis and in cellular response to DNA-damaging treatments. S6K1 is an effector and a mediator of mTOR complex 1 (mTORC1) in regulating protein synthesis and integrating diverse signals into control of cell growth and response to stress. Here, we show that eIF3a regulates S6K1 activity by inhibiting mTORC1 kinase via regulating Raptor synthesis. The regulation of Raptor synthesis is via eIF3a interaction with HuR (human antigen R) and binding of the eIF3a-HuR complex to the 5'-UTR of Raptor mRNA. Furthermore, mTORC1 may mediate eIF3a function in cellular response to cisplatin by regulating synthesis of NER proteins and NER activity. Taken together, we conclude that the mTOR signaling pathway may also be regulated by translational control and mediate eIF3a regulation of cancer cell response to cisplatin by regulating NER protein synthesis.
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13
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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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14
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Hayek H, Gross L, Janvier A, Schaeffer L, Martin F, Eriani G, Allmang C. eIF3 interacts with histone H4 messenger RNA to regulate its translation. J Biol Chem 2021; 296:100578. [PMID: 33766559 PMCID: PMC8102920 DOI: 10.1016/j.jbc.2021.100578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/15/2021] [Accepted: 03/21/2021] [Indexed: 11/23/2022] Open
Abstract
In eukaryotes, various alternative translation initiation mechanisms have been unveiled for the translation of specific mRNAs. Some do not conform to the conventional scanning-initiation model. Translation initiation of histone H4 mRNA combines both canonical (cap-dependent) and viral initiation strategies (no-scanning, internal recruitment of initiation factors). Specific H4 mRNA structures tether the translation machinery directly onto the initiation codon and allow massive production of histone H4 during the S phase of the cell cycle. The human eukaryotic translation initiation factor 3 (eIF3), composed of 13 subunits (a-m), was shown to selectively recruit and control the expression of several cellular mRNAs. Whether eIF3 mediates H4 mRNA translation remains to be elucidated. Here, we report that eIF3 binds to a stem-loop structure (eIF3-BS) located in the coding region of H4 mRNA. Combining cross-linking and ribonucleoprotein immunoprecipitation experiments in vivo and in vitro, we also found that eIF3 binds to H1, H2A, H2B, and H3 histone mRNAs. We identified direct contacts between eIF3c, d, e, g subunits, and histone mRNAs but observed distinct interaction patterns to each histone mRNA. Our results show that eIF3 depletion in vivo reduces histone mRNA binding and modulates histone neosynthesis, suggesting that synthesis of histones is sensitive to the levels of eIF3. Thus, we provide evidence that eIF3 acts as a regulator of histone translation.
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Affiliation(s)
- Hassan Hayek
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Lauriane Gross
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Aurélie Janvier
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Laure Schaeffer
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Franck Martin
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France.
| | - Christine Allmang
- Architecture et Réactivité de l'ARN, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France.
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15
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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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16
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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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17
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Wagner S, Herrmannová A, Hronová V, Gunišová S, Sen ND, Hannan RD, Hinnebusch AG, Shirokikh NE, Preiss T, Valášek LS. Selective Translation Complex Profiling Reveals Staged Initiation and Co-translational Assembly of Initiation Factor Complexes. Mol Cell 2020; 79:546-560.e7. [PMID: 32589964 PMCID: PMC7447980 DOI: 10.1016/j.molcel.2020.06.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/10/2020] [Accepted: 05/18/2020] [Indexed: 11/25/2022]
Abstract
Translational control targeting the initiation phase is central to the regulation of gene expression. Understanding all of its aspects requires substantial technological advancements. Here we modified yeast translation complex profile sequencing (TCP-seq), related to ribosome profiling, and adapted it for mammalian cells. Human TCP-seq, capable of capturing footprints of 40S subunits (40Ss) in addition to 80S ribosomes (80Ss), revealed that mammalian and yeast 40Ss distribute similarly across 5'TRs, indicating considerable evolutionary conservation. We further developed yeast and human selective TCP-seq (Sel-TCP-seq), enabling selection of 40Ss and 80Ss associated with immuno-targeted factors. Sel-TCP-seq demonstrated that eIF2 and eIF3 travel along 5' UTRs with scanning 40Ss to successively dissociate upon AUG recognition; notably, a proportion of eIF3 lingers on during the initial elongation cycles. Highlighting Sel-TCP-seq versatility, we also identified four initiating 48S conformational intermediates, provided novel insights into ATF4 and GCN4 mRNA translational control, and demonstrated co-translational assembly of initiation factor complexes.
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Affiliation(s)
- Susan Wagner
- EMBL-Australia Collaborating Group, Department of Genome Sciences, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; 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
| | - Vladislava Hronová
- 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
| | - Neelam D Sen
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ross D Hannan
- Australian Cancer Research Foundation Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Alan G Hinnebusch
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - 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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18
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Miller M, Mellul A, Braun M, Sherill-Rofe D, Cohen E, Shpilt Z, Unterman I, Braitbard O, Hochman J, Tshuva EY, Tabach Y. Titanium Tackles the Endoplasmic Reticulum: A First Genomic Study on a Titanium Anticancer Metallodrug. iScience 2020; 23:101262. [PMID: 32585595 PMCID: PMC7322074 DOI: 10.1016/j.isci.2020.101262] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/07/2020] [Accepted: 06/05/2020] [Indexed: 12/23/2022] Open
Abstract
PhenolaTi is an advanced non-toxic anticancer chemotherapy; this inert bis(phenolato)bis(alkoxo) Ti(IV) complex demonstrates the intriguing combination of high and wide efficacy with no detected toxicity in animals. Here we unravel the cellular pathways involved in its mechanism of action by a first genome study on Ti(IV)-treated cells, using an attuned RNA sequencing-based available technology. First, phenolaTi induced apoptosis and cell-cycle arrest at the G2/M phase in MCF7 cells. Second, the transcriptome of the treated cells was analyzed, identifying alterations in pathways relating to protein translation, DNA damage, and mitochondrial eruption. Unlike for common metallodrugs, electrophoresis assay showed no inhibition of DNA polymerase activity. Reduced in vitro cytotoxicity with added endoplasmic reticulum (ER) stress inhibitor supported the ER as a putative cellular target. Altogether, this paper reveals a distinct ER-related mechanism by the Ti(IV) anticancer coordination complex, paving the way for wider applicability of related techniques in mechanistic analyses of metallodrugs.
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Affiliation(s)
- Maya Miller
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Anna Mellul
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Maya Braun
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Dana Sherill-Rofe
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Emiliano Cohen
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Zohar Shpilt
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Irene Unterman
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Ori Braitbard
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Jacob Hochman
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Edit Y Tshuva
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
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19
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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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20
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eIF3 Associates with 80S Ribosomes to Promote Translation Elongation, Mitochondrial Homeostasis, and Muscle Health. Mol Cell 2020; 79:575-587.e7. [PMID: 32589965 DOI: 10.1016/j.molcel.2020.06.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 12/06/2019] [Accepted: 06/01/2020] [Indexed: 12/28/2022]
Abstract
eIF3, a multi-subunit complex with numerous functions in canonical translation initiation, is known to interact with 40S and 60S ribosomal proteins and translation elongation factors, but a direct involvement in translation elongation has never been demonstrated. We found that eIF3 deficiency reduced early ribosomal elongation speed between codons 25 and 75 on a set of ∼2,700 mRNAs encoding proteins associated with mitochondrial and membrane functions, resulting in defective synthesis of their encoded proteins. To promote elongation, eIF3 interacts with 80S ribosomes translating the first ∼60 codons and serves to recruit protein quality-control factors, functions required for normal mitochondrial physiology. Accordingly, eIF3e+/- mice accumulate defective mitochondria in skeletal muscle and show a progressive decline in muscle strength. Hence, eIF3 interacts with 80S ribosomes to enhance, at the level of early elongation, the synthesis of proteins with membrane-associated functions, an activity that is critical for mitochondrial physiology and muscle health.
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21
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Genetic Profiles Playing Opposite Roles of Pathogenesis in Schizophrenia and Glioma. JOURNAL OF ONCOLOGY 2020; 2020:3656841. [PMID: 32565801 PMCID: PMC7275202 DOI: 10.1155/2020/3656841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 03/27/2020] [Indexed: 11/17/2022]
Abstract
Background Patients diagnosed with schizophrenia were found having lower risks to develop cancers, including glioma. Based on this epidemiology, we hypothesized that there were gene profiles playing opposite roles in pathogenesis of schizophrenia and glioma. Methods Based on GEO datasets and TCGA, key genes of schizophrenia genes on the opposite development of glioma were screened by different expressed genes (DEGs) screening, weighted gene coexpression network analysis (WGCNA), disease-specific survival (DSS), and glioma grading and verified by gene set enrichment analysis (GSEA). Results First, 612 DEGs were screened from schizophrenia and control brain samples. Second, 134 key genes more specific to schizophrenia were left by WGCNA, with 93 key genes having annotations in TCGA. Third, DSS of glioma helped to find 42 key gene expressions of schizophrenia oppositely associated with survival of glioma. Finally, 24 key genes showed opposite expression trends in schizophrenia and different glioma grading, i.e., the upregulated key genes in schizophrenia expressed increasingly in higher grade glioma, and vice versa. CAMK2D and MPC2 were taken as the examples and evaluated by GSEA, which indeed showed opposite trends in the same pathways of schizophrenia and glioma. Conclusion This workflow of selecting novel targeted genes which may have opposite roles in pathogenesis of two diseases was firstly and innovatively generated by our team. Some filtered key genes were indeed found by their potential effects in several mechanism studies, indicating our process could be effective to generate novel targeted genes. These 24 key genes may provide potential directions for future biochemical and pharmacotherapeutic research studies.
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22
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Poncová K, Wagner S, Jansen ME, Beznosková P, Gunišová S, Herrmannová A, Zeman J, Dong J, Valášek LS. uS3/Rps3 controls fidelity of translation termination and programmed stop codon readthrough in co-operation with eIF3. Nucleic Acids Res 2020; 47:11326-11343. [PMID: 31642471 PMCID: PMC6868437 DOI: 10.1093/nar/gkz929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 12/27/2022] Open
Abstract
Ribosome was long considered as a critical yet passive player in protein synthesis. Only recently the role of its basic components, ribosomal RNAs and proteins, in translational control has begun to emerge. Here we examined function of the small ribosomal protein uS3/Rps3, earlier shown to interact with eukaryotic translation initiation factor eIF3, in termination. We identified two residues in consecutive helices occurring in the mRNA entry pore, whose mutations to the opposite charge either reduced (K108E) or increased (R116D) stop codon readthrough. Whereas the latter increased overall levels of eIF3-containing terminating ribosomes in heavy polysomes in vivo indicating slower termination rates, the former specifically reduced eIF3 amounts in termination complexes. Combining these two mutations with the readthrough-reducing mutations at the extreme C-terminus of the a/Tif32 subunit of eIF3 either suppressed (R116D) or exacerbated (K108E) the readthrough phenotypes, and partially corrected or exacerbated the defects in the composition of termination complexes. In addition, we found that K108 affects efficiency of termination in the termination context-specific manner by promoting incorporation of readthrough-inducing tRNAs. Together with the multiple binding sites that we identified between these two proteins, we suggest that Rps3 and eIF3 closely co-operate to control translation termination and stop codon readthrough.
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Affiliation(s)
- Kristýna Poncová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic.,Charles University, Faculty of Science, Prague, the Czech Republic
| | - Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Myrte Esmeralda Jansen
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Stanislava Gunišová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Jinsheng Dong
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
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23
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Li J, Yu W, Ge J, Zhang J, Wang Y, Wang P, Shi G. Targeting eIF3f Suppresses the Growth of Prostate Cancer Cells by Inhibiting Akt Signaling. Onco Targets Ther 2020; 13:3739-3750. [PMID: 32440143 PMCID: PMC7210466 DOI: 10.2147/ott.s244345] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 04/10/2020] [Indexed: 01/14/2023] Open
Abstract
Background Eukaryotic initiation factor 3 (eIF3) is the largest translation initiation factor, and oncogenic roles have been discovered for its subunits, including the f subunit (ie, eIF3f), in various human cancers. However, the roles of eIF3f in the development and progression of prostate cancer (PCa) have not been reported. Materials and Methods We performed in silico analysis to screen the expression of eIF3 subunits. Relevant shRNAs were used to knock down eIF3 subunits in 22Rv1 cells and cell proliferation was analyzed. eIF3f expression in PCa specimens was confirmed by immunohistochemistry. eIF3f knockdown was established to evaluate the effects of eIF3f on cell proliferation in vitro and in vivo. RNA‐seq, bioinformatics analysis and Western blotting were applied to explore the molecular details underlying the biological function of eIF3f in PCa cells. shRNA-resistant eIF3f and myristoylated-Akt were used to rescue the effects of eIF3f disturbance on PCa cells. Results Functional analyses confirmed that eIF3f is essential for PCa proliferation. Notably, the expression of eIF3f was found to be elevated in human PCa tissues as well as in PCa cell lines. eIF3f silencing significantly suppressed the growth of PCa cells, both in vitro and in vivo. eIF3f expression was positively correlated with Akt signaling activity in RNA-seq profiles and published prostate cohorts. Knockdown of eIF3f markedly reduced the levels of phosphorylated Akt in PCa cells. Exogenous expression of shRNA-resistant eIF3f in eIF3f knockdown cells restored Akt phosphorylation levels and cell growth. Importantly, rescue experiments revealed that ectopic expression of myristoylated-Akt partially alleviated the suppressive effects of eIF3f disturbance with respect to the growth of PCa cells. Conclusion These results suggested that eIF3f has an oncogenic role in PCa, mediated at least partially through the regulation of Akt signaling, and that eIF3f represents a potential target for the inhibition of PCa growth and progression.
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Affiliation(s)
- Junhong Li
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Wandong Yu
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Jianchao Ge
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Jun Zhang
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Yang Wang
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Pengyu Wang
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
| | - Guowei Shi
- Department of Urology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, People's Republic of China
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24
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Herrmannová A, Prilepskaja T, Wagner S, Šikrová D, Zeman J, Poncová K, Valášek LS. Adapted formaldehyde gradient cross-linking protocol implicates human eIF3d and eIF3c, k and l subunits in the 43S and 48S pre-initiation complex assembly, respectively. Nucleic Acids Res 2020; 48:1969-1984. [PMID: 31863585 PMCID: PMC7039009 DOI: 10.1093/nar/gkz1185] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/04/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022] Open
Abstract
One of the key roles of the 12-subunit eukaryotic translation initiation factor 3 (eIF3) is to promote the formation of the 43S and 48S pre-initiation complexes (PICs). However, particular contributions of its individual subunits to these two critical initiation reactions remained obscure. Here, we adapted formaldehyde gradient cross-linking protocol to translation studies and investigated the efficiency of the 43S and 48S PIC assembly in knockdowns of individual subunits of human eIF3 known to produce various partial subcomplexes. We revealed that eIF3d constitutes an important intermolecular bridge between eIF3 and the 40S subunit as its elimination from the eIF3 holocomplex severely compromised the 43S PIC assembly. Similarly, subunits eIF3a, c and e were found to represent an important binding force driving eIF3 binding to the 40S subunit. In addition, we demonstrated that eIF3c, and eIF3k and l subunits alter the efficiency of mRNA recruitment to 43S PICs in an opposite manner. Whereas the eIF3c knockdown reduces it, downregulation of eIF3k or eIF3l increases mRNA recruitment, suggesting that the latter subunits possess a regulatory potential. Altogether this study provides new insights into the role of human eIF3 in the initial assembly steps of the translational machinery.
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Affiliation(s)
- Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Terezie Prilepskaja
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Darina Šikrová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Kristýna Poncová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
| | - Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Videnska 1083, 142 20, the Czech Republic
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25
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Overexpression of eIF3D in Lung Adenocarcinoma Is a New Independent Prognostic Marker of Poor Survival. DISEASE MARKERS 2019; 2019:6019637. [PMID: 31885740 PMCID: PMC6925810 DOI: 10.1155/2019/6019637] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/02/2019] [Accepted: 09/26/2019] [Indexed: 12/16/2022]
Abstract
The eukaryotic initiation factor 3 (eIF3) is the largest and most complex translation initiation factor in mammalian cells. It consists of 13 subunits and among which several were implicated to have significant prognostic effects on multiple human cancer entities. To examine the expression profiles of eIF3 subunits and determine their prognostic value in patients with lung adenocarcinoma (LUAD), the genomic data, survival data, and related clinical information were obtained from The Cancer Genome Atlas (TCGA) project for a secondary analysis. The results showed that among ten aberrantly expressed eIF3 subunits in tumours compared with adjacent normal counterparts (p < 0.05), only upregulated eIF3D could predict poor overall survival (OS) outcome independent of multiple clinicopathological parameters (HR = 2.043, 95% CI: 1.132-3.689, p = 0.018). Chi-square analysis revealed that the highly expressed eIF3D group had larger ratios of patients with advanced pathological stage (68/40 vs. 184/206, p = 0.0046), residual tumour (13/4 vs. 163/176, p = 0.0257), and targeted molecular therapy (85/65 vs. 138/164, p = 0.0357). In silico analysis demonstrated that the altered expression of eIF3D was at least regulated by both copy number alterations (CNAs) and the hypomethylation of cg14297023 site. In conclusion, high eIF3D expression might serve as a valuable independent prognostic indicator of shorter OS in patients with LUAD.
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26
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Raabe K, Honys D, Michailidis C. The role of eukaryotic initiation factor 3 in plant translation regulation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 145:75-83. [PMID: 31665669 DOI: 10.1016/j.plaphy.2019.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/07/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Regulation of translation represents a critical step in the regulation of gene expression. In plants, the translation regulation plays an important role at all stages of development and, during stress responses, functions as a fast and flexible tool which not only modulates the global translation rate but also controls the production of specific proteins. Regulation of translation is mostly focused on the initiation phase. There, one of essential initiation factors is the large multisubunit protein complex of eukaryotic translation initiation factor 3 (eIF3). In all eukaryotes, the general eIF3 function is to scaffold the formation of the translation initiation complex and to enhance the accuracy of scanning mechanism for start codon selection. Over the past decades, additional eIF3 functions were described as necessary for development in various eukaryotic organisms, including plants. The importance of the eIF3 complex lies not only at the global level of initiation event, but also in the precise translation regulation of specific transcripts. This review gathers the available information on functions of the plant eIF3 complex.
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Affiliation(s)
- Karel Raabe
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Christos Michailidis
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic.
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27
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Sousa A, Gonçalves E, Mirauta B, Ochoa D, Stegle O, Beltrao P. Multi-omics Characterization of Interaction-mediated Control of Human Protein Abundance levels. Mol Cell Proteomics 2019; 18:S114-S125. [PMID: 31239291 PMCID: PMC6692786 DOI: 10.1074/mcp.ra118.001280] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/07/2019] [Indexed: 11/13/2022] Open
Abstract
Proteogenomic studies of cancer samples have shown that copy-number variation can be attenuated at the protein level for a large fraction of the proteome, likely due to the degradation of unassembled protein complex subunits. Such interaction-mediated control of protein abundance remains poorly characterized. To study this, we compiled genomic, (phospho)proteomic and structural data for hundreds of cancer samples and find that up to 42% of 8,124 analyzed proteins show signs of post-transcriptional control. We find evidence of interaction-dependent control of protein abundance, correlated with interface size, for 516 protein pairs, with some interactions further controlled by phosphorylation. Finally, these findings in cancer were reflected in variation in protein levels in normal tissues. Importantly, expression differences due to natural genetic variation were increasingly buffered from phenotype differences for highly attenuated proteins. Altogether, this study further highlights the importance of posttranscriptional control of protein abundance in cancer and healthy cells.
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Affiliation(s)
- Abel Sousa
- Instituto de Investigação e Inovação em Saúde da Universidade do Porto (i3s), Rua Alfredo Allen 208, 4200-135, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua Júlio Amaral de Carvalho 45, 4200-135, Porto, Portugal; Graduate Program in Areas of Basic and Applied Biology (GABBA), Abel Salazar Biomedical Sciences Institute, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal; European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, Cambridge, UK
| | | | - Bogdan Mirauta
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, Cambridge, UK
| | - David Ochoa
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, Cambridge, UK
| | - Oliver Stegle
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, Cambridge, UK; ‡European Molecular Biology Laboratory, Genome Biology Unit, 69117 Heidelberg, Germany; §Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Pedro Beltrao
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, Cambridge, UK.
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28
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Genuth NR, Barna M. Heterogeneity and specialized functions of translation machinery: from genes to organisms. Nat Rev Genet 2019; 19:431-452. [PMID: 29725087 DOI: 10.1038/s41576-018-0008-z] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Regulation of mRNA translation offers the opportunity to diversify the expression and abundance of proteins made from individual gene products in cells, tissues and organisms. Emerging evidence has highlighted variation in the composition and activity of several large, highly conserved translation complexes as a means to differentially control gene expression. Heterogeneity and specialized functions of individual components of the ribosome and of the translation initiation factor complexes eIF3 and eIF4F, which are required for recruitment of the ribosome to the mRNA 5' untranslated region, have been identified. In this Review, we summarize the evidence for selective mRNA translation by components of these macromolecular complexes as a means to dynamically control the translation of the proteome in time and space. We further discuss the implications of this form of gene expression regulation for a growing number of human genetic disorders associated with mutations in the translation machinery.
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Affiliation(s)
- Naomi R Genuth
- Departments of Genetics and Developmental Biology, Stanford University, Stanford, CA, USA.,Department of Biology, Stanford University, Stanford, CA, USA
| | - Maria Barna
- Departments of Genetics and Developmental Biology, Stanford University, Stanford, CA, USA.
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29
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Eliseev B, Yeramala L, Leitner A, Karuppasamy M, Raimondeau E, Huard K, Alkalaeva E, Aebersold R, Schaffitzel C. Structure of a human cap-dependent 48S translation pre-initiation complex. Nucleic Acids Res 2019; 46:2678-2689. [PMID: 29401259 PMCID: PMC5861459 DOI: 10.1093/nar/gky054] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 01/21/2018] [Indexed: 01/13/2023] Open
Abstract
Eukaryotic translation initiation is tightly regulated, requiring a set of conserved initiation factors (eIFs). Translation of a capped mRNA depends on the trimeric eIF4F complex and eIF4B to load the mRNA onto the 43S pre-initiation complex comprising 40S and initiation factors 1, 1A, 2, 3 and 5 as well as initiator-tRNA. Binding of the mRNA is followed by mRNA scanning in the 48S pre-initiation complex, until a start codon is recognised. Here, we use a reconstituted system to prepare human 48S complexes assembled on capped mRNA in the presence of eIF4B and eIF4F. The highly purified h-48S complexes are used for cross-linking/mass spectrometry, revealing the protein interaction network in this complex. We report the electron cryo-microscopy structure of the h-48S complex at 6.3 Å resolution. While the majority of eIF4B and eIF4F appear to be flexible with respect to the ribosome, additional density is detected at the entrance of the 40S mRNA channel which we attribute to the RNA-recognition motif of eIF4B. The eight core subunits of eIF3 are bound at the 40S solvent-exposed side, as well as the subunits eIF3d, eIF3b and eIF3i. elF2 and initiator-tRNA bound to the start codon are present at the 40S intersubunit side. This cryo-EM structure represents a molecular snap-shot revealing the h-48S complex following start codon recognition.
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Affiliation(s)
- Boris Eliseev
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Lahari Yeramala
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Alexander Leitner
- ETH Zürich, Institute of Molecular Systems Biology, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland
| | - Manikandan Karuppasamy
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Etienne Raimondeau
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Karine Huard
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Ruedi Aebersold
- ETH Zürich, Institute of Molecular Systems Biology, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.,Faculty of Science, University of Zürich, 8057 Zürich, Switzerland
| | - Christiane Schaffitzel
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France.,School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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30
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Hu J, Luo H, Xu Y, Luo G, Xu S, Zhu J, Song D, Sun Z, Kuang Y. The Prognostic Significance of EIF3C Gene during the Tumorigenesis of Prostate Cancer. Cancer Invest 2019; 37:199-208. [PMID: 31181967 DOI: 10.1080/07357907.2019.1618322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Jianxin Hu
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Heng Luo
- Key Laboratory of Chemistry for Natural Products of Guizhou Province, Chinese Academy of Sciences, Guiyang, PR China
| | - Yuangao Xu
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Guangheng Luo
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Shuxiong Xu
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Jianguo Zhu
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Dalong Song
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Zhaolin Sun
- Department of Urology, Guizhou Provincial people’s Hospital, Guiyang, PR China
| | - Youlin Kuang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
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31
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Shintani T, Higashisaka K, Maeda M, Hamada M, Tsuji R, Kurihara K, Kashiwagi Y, Sato A, Obana M, Yamamoto A, Kawasaki K, Lin Y, Kijima T, Kinehara Y, Miwa Y, Maeda S, Morii E, Kumanogoh A, Tsutsumi Y, Nagatomo I, Fujio Y. Eukaryotic translation initiation factor 3 subunit C is associated with acquired resistance to erlotinib in non-small cell lung cancer. Oncotarget 2018; 9:37520-37533. [PMID: 30680067 PMCID: PMC6331022 DOI: 10.18632/oncotarget.26494] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/10/2018] [Indexed: 12/20/2022] Open
Abstract
The acquisition of resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) is one of the major problems in the pharmacotherapy against non-small cell lung cancers; however, molecular mechanisms remain to be fully elucidated. Here, using a newly-established erlotinib-resistant cell line, PC9/ER, from PC9 lung cancer cells, we demonstrated that the expression of translation-related molecules, including eukaryotic translation initiation factor 3 subunit C (eIF3c), was upregulated in PC9/ER cells by proteome analyses. Immunoblot analyses confirmed that eIF3c protein increased in PC9/ER cells, compared with PC9 cells. Importantly, the knockdown of eIF3c with its siRNAs enhanced the drug sensitivity in PC9/ER cells. Mechanistically, we found that LC3B-II was upregulated in PC9/ER cells, while downregulated by the knockdown of eIF3c. Consistently, the overexpression of eIF3c increased the number of autophagosomes, proposing the causality between eIF3c expression and autophagy. Moreover, chloroquine, an autophagy inhibitor, restored the sensitivity to erlotinib. Finally, immunohistochemical analyses of biopsy samples showed that the frequency of eIF3c-positive cases was higher in the patients with EGFR-TKI resistance than those prior to EGFR-TKI treatment. Moreover, the eIF3c-positive cases exhibited poor prognosis in EGFR-TKI treatment. Collectively, the upregulation of eIF3c could impair the sensitivity to EGFR-TKI as a novel mechanism of the drug resistance.
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Affiliation(s)
- Takuya Shintani
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,Department of Pharmacy, Osaka University Hospital, Suita, Japan
| | - Kazuma Higashisaka
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,Department of Legal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Makiko Maeda
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Masaya Hamada
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Ryosuke Tsuji
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Koudai Kurihara
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Yuri Kashiwagi
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Atsuhiro Sato
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Masanori Obana
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Ayaha Yamamoto
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Keisuke Kawasaki
- Department of Pathology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ying Lin
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Takashi Kijima
- Division of Respiratory Medicine, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.,Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yuhei Kinehara
- Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yoshihiro Miwa
- Department of Pharmacy, Osaka University Hospital, Suita, Japan
| | - Shinichiro Maeda
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,Department of Pharmacy, Osaka University Hospital, Suita, Japan
| | - Eiichi Morii
- Department of Pathology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Atsushi Kumanogoh
- Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Suita, Japan.,Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan
| | - Yasuo Tsutsumi
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,The Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan
| | - Izumi Nagatomo
- Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yasushi Fujio
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan
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32
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Cuesta R, Berman AY, Alayev A, Holz MK. Estrogen receptor α promotes protein synthesis by fine-tuning the expression of the eukaryotic translation initiation factor 3 subunit f (eIF3f). J Biol Chem 2018; 294:2267-2278. [PMID: 30573685 DOI: 10.1074/jbc.ra118.004383] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 12/18/2018] [Indexed: 01/09/2023] Open
Abstract
Approximately two thirds of all breast cancer cases are estrogen receptor (ER)-positive. The treatment of this breast cancer subtype with endocrine therapies is effective in the adjuvant and recurrent settings. However, their effectiveness is compromised by the emergence of intrinsic or acquired resistance. Thus, identification of new molecular targets can significantly contribute to the development of novel therapeutic strategies. In recent years, many studies have implicated aberrant levels of translation initiation factors in cancer etiology and provided evidence that identifies these factors as promising therapeutic targets. Accordingly, we observed reduced levels of the eIF3 subunit eIF3f in ER-positive breast cancer cells compared with ER-negative cells, and determined that low eIF3f levels are required for proper proliferation and survival of ER-positive MCF7 cells. The expression of eIF3f is tightly controlled by ERα at the transcriptional (genomic pathway) and translational (nongenomic pathway) level. Specifically, estrogen-bound ERα represses transcription of the EIF3F gene, while promoting eIF3f mRNA translation. To regulate translation, estrogen activates the mTORC1 pathway, which enhances the binding of eIF3 to the eIF4F complex and, consequently, the assembly of the 48S preinitiation complexes and protein synthesis. We observed preferential translation of mRNAs with highly structured 5'-UTRs that usually encode factors involved in cell proliferation and survival (e.g. cyclin D1 and survivin). Our results underscore the importance of estrogen-ERα-mediated control of eIF3f expression for the proliferation and survival of ER-positive breast cancer cells. These findings may provide rationale for the development of new therapies to treat ER-positive breast cancer.
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Affiliation(s)
- Rafael Cuesta
- From the Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595
| | - Adi Y Berman
- the Department of Biology, Yeshiva University, New York, New York 10016, and
| | - Anya Alayev
- the Department of Biology, Yeshiva University, New York, New York 10016, and
| | - Marina K Holz
- From the Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595, .,Albert Einstein Cancer Center, Bronx, New York 10461
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33
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Riemondy KA, Gillen AE, White EA, Bogren LK, Hesselberth JR, Martin SL. Dynamic temperature-sensitive A-to-I RNA editing in the brain of a heterothermic mammal during hibernation. RNA (NEW YORK, N.Y.) 2018; 24:1481-1495. [PMID: 30065024 PMCID: PMC6191720 DOI: 10.1261/rna.066522.118] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
RNA editing diversifies genomically encoded information to expand the complexity of the transcriptome. In ectothermic organisms, including Drosophila and Cephalopoda, where body temperature mirrors ambient temperature, decreases in environmental temperature lead to increases in A-to-I RNA editing and cause amino acid recoding events that are thought to be adaptive responses to temperature fluctuations. In contrast, endothermic mammals, including humans and mice, typically maintain a constant body temperature despite environmental changes. Here, A-to-I editing primarily targets repeat elements, rarely results in the recoding of amino acids, and plays a critical role in innate immune tolerance. Hibernating ground squirrels provide a unique opportunity to examine RNA editing in a heterothermic mammal whose body temperature varies over 30°C and can be maintained at 5°C for many days during torpor. We profiled the transcriptome in three brain regions at six physiological states to quantify RNA editing and determine whether cold-induced RNA editing modifies the transcriptome as a potential mechanism for neuroprotection at low temperature during hibernation. We identified 5165 A-to-I editing sites in 1205 genes with dynamically increased editing after prolonged cold exposure. The majority (99.6%) of the cold-increased editing sites are outside of previously annotated coding regions, 82.7% lie in SINE-derived repeats, and 12 sites are predicted to recode amino acids. Additionally, A-to-I editing frequencies increase with increasing cold-exposure, demonstrating that ADAR remains active during torpor. Our findings suggest that dynamic A-to-I editing at low body temperature may provide a neuroprotective mechanism to limit aberrant dsRNA accumulation during torpor in the mammalian hibernator.
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Affiliation(s)
- Kent A Riemondy
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Austin E Gillen
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Emily A White
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | | | - Jay R Hesselberth
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Sandra L Martin
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- Department of Cell and Developmental Biology
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Hutt DM, Loguercio S, Roth DM, Su AI, Balch WE. Correcting the F508del-CFTR variant by modulating eukaryotic translation initiation factor 3-mediated translation initiation. J Biol Chem 2018; 293:13477-13495. [PMID: 30006345 DOI: 10.1074/jbc.ra118.003192] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/05/2018] [Indexed: 12/31/2022] Open
Abstract
Inherited and somatic rare diseases result from >200,000 genetic variants leading to loss- or gain-of-toxic function, often caused by protein misfolding. Many of these misfolded variants fail to properly interact with other proteins. Understanding the link between factors mediating the transcription, translation, and protein folding of these disease-associated variants remains a major challenge in cell biology. Herein, we utilized the cystic fibrosis transmembrane conductance regulator (CFTR) protein as a model and performed a proteomics-based high-throughput screen (HTS) to identify pathways and components affecting the folding and function of the most common cystic fibrosis-associated mutation, the F508del variant of CFTR. Using a shortest-path algorithm we developed, we mapped HTS hits to the CFTR interactome to provide functional context to the targets and identified the eukaryotic translation initiation factor 3a (eIF3a) as a central hub for the biogenesis of CFTR. Of note, siRNA-mediated silencing of eIF3a reduced the polysome-to-monosome ratio in F508del-expressing cells, which, in turn, decreased the translation of CFTR variants, leading to increased CFTR stability, trafficking, and function at the cell surface. This finding suggested that eIF3a is involved in mediating the impact of genetic variations in CFTR on the folding of this protein. We posit that the number of ribosomes on a CFTR mRNA transcript is inversely correlated with the stability of the translated polypeptide. Polysome-based translation challenges the capacity of the proteostasis environment to balance message fidelity with protein folding, leading to disease. We suggest that this deficit can be corrected through control of translation initiation.
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Affiliation(s)
| | | | | | - Andrew I Su
- Integrative Structural and Computational Biology and
| | - William E Balch
- From the Departments of Molecular Medicine and .,the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
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Elevated expression of eukaryotic translation initiation factor 3H is associated with proliferation, invasion and tumorigenicity in human hepatocellular carcinoma. Oncotarget 2018; 7:49888-49901. [PMID: 27340783 PMCID: PMC5226555 DOI: 10.18632/oncotarget.10222] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 06/04/2016] [Indexed: 01/05/2023] Open
Abstract
Aim We studied the role of eukaryotic translation initiation factor 3 subunit H (EIF3H) in hepatocellular carcinoma (HCC) progression. Results High EIF3H expression was observed in 50.23% patients. Upregulation of EIF3H is an independent predictor for greater rates of cancer recurrence and shorter overall survival in HCC patients. Knockdown of EIF3H expression in HCC cells promoted apoptosis, and inhibited cell growth, colony formation, migration, as well as xenograft growth. TGF-βand MAPK pathways are potentially targeted by EIF3H. Methods EIF3H mRNA expression was measured in HCC tissue samples and paired non-tumor samples (N=60) and results were validated in another dataset of 215 HCC patients. Then EIF3H expression and clinical outcomes were correlated. Malignant phenotypes were studied after EIF3H expression was knocked down with siRNA in HCC cell lines. EIF3H targeted pathways were identified by microarray analysis. Conclusion EIF3H is frequently upregulated and is an independent prognostic marker for HCC patients and EIF3H inhibition mitigates the malignant phenotype. Our data provide novel insight into the function of EIF3H in HCC progression, and suggest that EIF3H may be a potentially valuable biomarker for HCC.
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36
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Liu HH, McClatchy DB, Schiapparelli L, Shen W, Yates JR, Cline HT. Role of the visual experience-dependent nascent proteome in neuronal plasticity. eLife 2018; 7:e33420. [PMID: 29412139 PMCID: PMC5815848 DOI: 10.7554/elife.33420] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/05/2018] [Indexed: 01/02/2023] Open
Abstract
Experience-dependent synaptic plasticity refines brain circuits during development. To identify novel protein synthesis-dependent mechanisms contributing to experience-dependent plasticity, we conducted a quantitative proteomic screen of the nascent proteome in response to visual experience in Xenopus optic tectum using bio-orthogonal metabolic labeling (BONCAT). We identified 83 differentially synthesized candidate plasticity proteins (CPPs). The CPPs form strongly interconnected networks and are annotated to a variety of biological functions, including RNA splicing, protein translation, and chromatin remodeling. Functional analysis of select CPPs revealed the requirement for eukaryotic initiation factor three subunit A (eIF3A), fused in sarcoma (FUS), and ribosomal protein s17 (RPS17) in experience-dependent structural plasticity in tectal neurons and behavioral plasticity in tadpoles. These results demonstrate that the nascent proteome is dynamic in response to visual experience and that de novo synthesis of machinery that regulates RNA splicing and protein translation is required for experience-dependent plasticity.
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Affiliation(s)
- Han-Hsuan Liu
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Kellogg School of Science and TechnologyThe Scripps Research InstituteLa JollaUnited States
| | - Daniel B McClatchy
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
| | - Lucio Schiapparelli
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
| | - Wanhua Shen
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental SciencesHangzhou Normal UniversityHangzhouChina
| | - John R Yates
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
| | - Hollis T Cline
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Kellogg School of Science and TechnologyThe Scripps Research InstituteLa JollaUnited States
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
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A Unique ISR Program Determines Cellular Responses to Chronic Stress. Mol Cell 2017; 68:885-900.e6. [PMID: 29220654 DOI: 10.1016/j.molcel.2017.11.007] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 09/27/2017] [Accepted: 11/07/2017] [Indexed: 02/05/2023]
Abstract
The integrated stress response (ISR) is a homeostatic mechanism induced by endoplasmic reticulum (ER) stress. In acute/transient ER stress, decreased global protein synthesis and increased uORF mRNA translation are followed by normalization of protein synthesis. Here, we report a dramatically different response during chronic ER stress. This chronic ISR program is characterized by persistently elevated uORF mRNA translation and concurrent gene expression reprogramming, which permits simultaneous stress sensing and proteostasis. The program includes PERK-dependent switching to an eIF3-dependent translation initiation mechanism, resulting in partial, but not complete, translational recovery, which, together with transcriptional reprogramming, selectively bolsters expression of proteins with ER functions. Coordination of transcriptional and translational reprogramming prevents ER dysfunction and inhibits "foamy cell" development, thus establishing a molecular basis for understanding human diseases associated with ER dysfunction.
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38
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Valášek LS, Zeman J, Wagner S, Beznosková P, Pavlíková Z, Mohammad MP, Hronová V, Herrmannová A, Hashem Y, Gunišová S. Embraced by eIF3: structural and functional insights into the roles of eIF3 across the translation cycle. Nucleic Acids Res 2017; 45:10948-10968. [PMID: 28981723 PMCID: PMC5737393 DOI: 10.1093/nar/gkx805] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
Protein synthesis is mediated via numerous molecules including the ribosome, mRNA, tRNAs, as well as translation initiation, elongation and release factors. Some of these factors play several roles throughout the entire process to ensure proper assembly of the preinitiation complex on the right mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most intriguing of these multitasking factors is the eukaryotic initiation factor eIF3. Recent evidence strongly suggests that this factor, which coordinates the progress of most of the initiation steps, does not come off the initiation complex upon subunit joining, but instead it remains bound to 80S ribosomes and gradually falls off during the first few elongation cycles to: (1) promote resumption of scanning on the same mRNA molecule for reinitiation downstream—in case of translation of upstream ORFs short enough to preserve eIF3 bound; or (2) come back during termination on long ORFs to fine tune its fidelity or, if signaled, promote programmed stop codon readthrough. Here, we unite recent structural views of the eIF3–40S complex and discus all known eIF3 roles to provide a broad picture of the eIF3’s impact on translational control in eukaryotic cells.
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Affiliation(s)
- Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Zuzana Pavlíková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Mahabub Pasha Mohammad
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Vladislava Hronová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Yaser Hashem
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France
| | - Stanislava Gunišová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
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Abstract
The eukaryotic initiation factor 3 (eIF3) is one of the most complex translation initiation factors in mammalian cells, consisting of several subunits (eIF3a to eIF3m). It is crucial in translation initiation and termination, and in ribosomal recycling. Accordingly, deregulated eIF3 expression is associated with different pathological conditions, including cancer. In this manuscript, we discuss the interactome and function of each subunit of the human eIF3 complex. Furthermore, we review how altered levels of eIF3 subunits correlate with neurodegenerative disorders and cancer onset and development; in addition, we evaluate how such misregulation may also trigger infection cascades. A deep understanding of the molecular mechanisms underlying eIF3 role in human disease is essential to develop new eIF3-targeted therapeutic approaches and thus, overcome such conditions.
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Affiliation(s)
- Andreia Gomes-Duarte
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Rafaela Lacerda
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Juliane Menezes
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Luísa Romão
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
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40
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Gonçalves E, Fragoulis A, Garcia-Alonso L, Cramer T, Saez-Rodriguez J, Beltrao P. Widespread Post-transcriptional Attenuation of Genomic Copy-Number Variation in Cancer. Cell Syst 2017; 5:386-398.e4. [PMID: 29032074 PMCID: PMC5660600 DOI: 10.1016/j.cels.2017.08.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/21/2017] [Accepted: 08/23/2017] [Indexed: 12/28/2022]
Abstract
Copy-number variations (CNVs) are ubiquitous in cancer and often act as driver events, but the effects of CNVs on the proteome of tumors are poorly understood. Here, we analyze recently published genomics, transcriptomics, and proteomics datasets made available by CPTAC and TCGA consortia on 282 breast, ovarian, and colorectal tumor samples to investigate the impact of CNVs in the proteomes of these cells. We found that CNVs are buffered by post-transcriptional regulation in 23%-33% of proteins that are significantly enriched in protein complex members. Our analyses show that complex subunits are highly co-regulated, and some act as rate-limiting steps of complex assembly, as their depletion induces decreased abundance of other complex members. We identified 48 such rate-limiting interactions and experimentally confirmed our predictions on the interactions of AP3B1 with AP3M1 and GTF2E2 with GTF2E1. This study highlights the importance of post-transcriptional mechanisms in cancer that allow cells to cope with their altered genomes.
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Affiliation(s)
- Emanuel Gonçalves
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK
| | - Athanassios Fragoulis
- Molecular Tumor Biology, Department of General, Visceral and Transplantation Surgery, RWTH University Hospital, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Luz Garcia-Alonso
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK
| | - Thorsten Cramer
- Molecular Tumor Biology, Department of General, Visceral and Transplantation Surgery, RWTH University Hospital, Pauwelsstraße 30, 52074 Aachen, Germany; NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands; ESCAM - European Surgery Center Aachen Maastricht, Germany and the Netherlands
| | - Julio Saez-Rodriguez
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK; RWTH Aachen University, Faculty of Medicine, Joint Research Centre for Computational Biomedicine, 52057 Aachen, Germany.
| | - Pedro Beltrao
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK.
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Hronová V, Mohammad MP, Wagner S, Pánek J, Gunišová S, Zeman J, Poncová K, Valášek LS. Does eIF3 promote reinitiation after translation of short upstream ORFs also in mammalian cells? RNA Biol 2017; 14:1660-1667. [PMID: 28745933 DOI: 10.1080/15476286.2017.1353863] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Reinitiation after translation of short upstream ORFs (uORFs) represents one of the means of regulation of gene expression on the mRNA-specific level in response to changing environmental conditions. Over the years it has been shown-mainly in budding yeast-that its efficiency depends on cis-acting features occurring in sequences flanking reinitiation-permissive uORFs, the nature of their coding sequences, as well as protein factors acting in trans. We earlier demonstrated that the first two uORFs from the reinitiation-regulated yeast GCN4 mRNA leader carry specific structural elements in their 5' sequences that interact with the translation initiation factor eIF3 to prevent full ribosomal recycling post their translation. Actually, this interaction turned out to be instrumental in stabilizing the mRNA·40S post-termination complex, which is thus capable to eventually resume scanning and reinitiate on the next AUG start site downstream. Recently, we also provided important in vivo evidence strongly supporting the long-standing idea that to stimulate reinitiation, eIF3 has to remain bound to ribosomes elongating these uORFs until their stop codon has been reached. Here we examined the importance of eIF3 and sequences flanking uORF1 of the human functional homolog of yeast GCN4, ATF4, in stimulation of efficient reinitiation. We revealed that the molecular basis of the reinitiation mechanism is conserved between yeasts and humans.
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Affiliation(s)
- Vladislava Hronová
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic.,b Department of Genetics and Microbiology, Faculty of Science , Charles University in Prague , Vinicna, Prague , the Czech Republic
| | - Mahabub Pasha Mohammad
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Susan Wagner
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Josef Pánek
- c Laboratory of Bioinformatics , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Stanislava Gunišová
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Jakub Zeman
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Kristýna Poncová
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
| | - Leoš Shivaya Valášek
- a Laboratory of Regulation of Gene Expression , Institute of Microbiology ASCR , Videnska, Prague , the Czech Republic
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Mancera-Martínez E, Brito Querido J, Valasek LS, Simonetti A, Hashem Y. ABCE1: A special factor that orchestrates translation at the crossroad between recycling and initiation. RNA Biol 2017; 14:1279-1285. [PMID: 28498001 PMCID: PMC5711452 DOI: 10.1080/15476286.2016.1269993] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
For many years initiation and termination of mRNA translation have been studied separately. However, a direct link between these 2 isolated stages has been suggested by the fact that some initiation factors also control termination and can even promote ribosome recycling; i.e. the last stage where post-terminating 80S ribosomes are split to start a new round of initiation. Notably, it is now firmly established that, among other factors, ribosomal recycling critically requires the NTPase ABCE1. However, several earlier reports have proposed that ABCE1 also somehow participates in the initiation complex assembly. Based on an extended analysis of our recently published late-stage 48S initiation complex from rabbit, here we provide new mechanistic insights into this putative role of ABCE1 in initiation. This point of view represents the first structural evidence in which the regulatory role of the recycling factor ABCE1 in initiation is discussed and establishes a corner stone for elucidating the interplay between ABCE1 and several initiation factors during the transit from ribosomal recycling to formation of the elongation competent 80S initiation complex.
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Affiliation(s)
- Eder Mancera-Martínez
- a CNRS , Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg , Strasbourg , France
| | - Jailson Brito Querido
- a CNRS , Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg , Strasbourg , France
| | - Leos Shivaya Valasek
- b Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR , Prague , Czech Republic
| | - Angelita Simonetti
- a CNRS , Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg , Strasbourg , France
| | - Yaser Hashem
- a CNRS , Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg , Strasbourg , France
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Lacerda R, Menezes J, Romão L. More than just scanning: the importance of cap-independent mRNA translation initiation for cellular stress response and cancer. Cell Mol Life Sci 2017; 74:1659-1680. [PMID: 27913822 PMCID: PMC11107732 DOI: 10.1007/s00018-016-2428-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/24/2016] [Accepted: 11/29/2016] [Indexed: 12/11/2022]
Abstract
The scanning model for eukaryotic mRNA translation initiation states that the small ribosomal subunit, along with initiation factors, binds at the cap structure at the 5' end of the mRNA and scans the 5' untranslated region (5'UTR) until an initiation codon is found. However, under conditions that impair canonical cap-dependent translation, the synthesis of some proteins is kept by alternative mechanisms that are required for cell survival and stress recovery. Alternative modes of translation initiation include cap- and/or scanning-independent mechanisms of ribosomal recruitment. In most cap-independent translation initiation events there is a direct recruitment of the 40S ribosome into a position upstream, or directly at, the initiation codon via a specific internal ribosome entry site (IRES) element in the 5'UTR. Yet, in some cellular mRNAs, a different translation initiation mechanism that is neither cap- nor IRES-dependent seems to occur through a special RNA structure called cap-independent translational enhancer (CITE). Recent evidence uncovered a distinct mechanism through which mRNAs containing N 6-methyladenosine (m6A) residues in their 5'UTR directly bind eukaryotic initiation factor 3 (eIF3) and the 40S ribosomal subunit in order to initiate translation in the absence of the cap-binding proteins. This review focuses on the important role of cap-independent translation mechanisms in human cells and how these alternative mechanisms can either act individually or cooperate with other cis-acting RNA regulons to orchestrate specific translational responses triggered upon several cellular stress states, and diseases such as cancer. Elucidation of these non-canonical mechanisms reveals the complexity of translational control and points out their potential as prospective novel therapeutic targets.
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Affiliation(s)
- Rafaela Lacerda
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Juliane Menezes
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Luísa Romão
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
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Li K, Zhou S, Guo Q, Chen X, Lai DH, Lun ZR, Guo X. The eIF3 complex of Trypanosoma brucei: composition conservation does not imply the conservation of structural assembly and subunits function. RNA (NEW YORK, N.Y.) 2017; 23:333-345. [PMID: 27932584 PMCID: PMC5311491 DOI: 10.1261/rna.058651.116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 11/24/2016] [Indexed: 05/03/2023]
Abstract
The multisubunit eukaryotic initiation factor 3 (eIF3) plays multiple roles in translation but is poorly understood in trypanosomes. The putative subunits eIF3a and eIF3f of Trypanosoma brucei (TbIF3a and TbIF3f) were overexpressed and purified, and 11 subunits were identified, TbIF3a through l minus j, which form a tight complex. Both TbIF3a and TbIF3f are essential for the viability of T. brucei RNAi knockdown of either of them severely reduced total translation and the ratio of the polysome/80S peak area. TbIF3f and TbIF3a RNAi cell lines were modified to express tagged-TbIF3a and -TbIF3f, respectively. RNAi in combination with affinity purification assays indicated that both subunits are variably required for TbIF3 stability and integrity. The relative abundance of other subunits in the TbIF3f-tag complex changed little upon TbIF3a depletion; while only subunits TbIF3b, i, and e copurified comparably with TbIF3a-tag upon TbIF3f depletion. A genome-wide UV-crosslinking assay showed that several TbIF3 subunits have direct RNA-binding activity, with TbIF3c showing the strongest signal. In addition, CrPV IRES, but neither EMCV IRES nor HCV IRES, was found to mediate translation in T. brucei These results together imply that the structure of TbIF3 and the subunits function have trypanosome-specific features, although the composition is evolutionarily conserved.
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Affiliation(s)
- Kunrao Li
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
| | - Shuru Zhou
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
| | - Qixuan Guo
- Chengde Nursing Vocational College, Chengde 067000, China
| | - Xin Chen
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
| | - De-Hua Lai
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zhao-Rong Lun
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xuemin Guo
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
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45
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Parasuraman P, Mulligan P, Walker JA, Li B, Boukhali M, Haas W, Bernards A. Interaction of p190A RhoGAP with eIF3A and Other Translation Preinitiation Factors Suggests a Role in Protein Biosynthesis. J Biol Chem 2016; 292:2679-2689. [PMID: 28007963 DOI: 10.1074/jbc.m116.769216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Indexed: 11/06/2022] Open
Abstract
The negative regulator of Rho family GTPases, p190A RhoGAP, is one of six mammalian proteins harboring so-called FF motifs. To explore the function of these and other p190A segments, we identified interacting proteins by tandem mass spectrometry. Here we report that endogenous human p190A, but not its 50% identical p190B paralog, associates with all 13 eIF3 subunits and several other translational preinitiation factors. The interaction involves the first FF motif of p190A and the winged helix/PCI domain of eIF3A, is enhanced by serum stimulation and reduced by phosphatase treatment. The p190A/eIF3A interaction is unaffected by mutating phosphorylated p190A-Tyr308, but disrupted by a S296A mutation, targeting the only other known phosphorylated residue in the first FF domain. The p190A-eIF3 complex is distinct from eIF3 complexes containing S6K1 or mammalian target of rapamycin (mTOR), and appears to represent an incomplete preinitiation complex lacking several subunits. Based on these findings we propose that p190A may affect protein translation by controlling the assembly of functional preinitiation complexes. Whether such a role helps to explain why, unique among the large family of RhoGAPs, p190A exhibits a significantly increased mutation rate in cancer remains to be determined.
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Affiliation(s)
- Prasanna Parasuraman
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Peter Mulligan
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - James A Walker
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Bihua Li
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Myriam Boukhali
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Wilhelm Haas
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Andre Bernards
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
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Lin Y, Zhang R, Zhang P. Eukaryotic translation initiation factor 3 subunit D overexpression is associated with the occurrence and development of ovarian cancer. FEBS Open Bio 2016; 6:1201-1210. [PMID: 28203520 PMCID: PMC5302064 DOI: 10.1002/2211-5463.12137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/29/2016] [Accepted: 09/21/2016] [Indexed: 12/24/2022] Open
Abstract
Ovarian cancer is the most common cause of gynaecological cancer-associated death; thus, promising biomarkers and new therapeutic targets for ovarian cancer must be explored. Here, we report that eukaryotic translation initiation factor 3 subunit D (EIF3D), a member of the EIF3 family, was overexpressed in ovarian cancer clinical tissues. Furthermore, the expression of EIF3D was correlated with the International Federation of Gynecology and Obstetrics stage and pathological differentiation stage. 3-(4,5-dimethylthylthiazol-2-yl)-2 (MTT) and colony formation assays revealed that the lentivirus-mediated knockdown of EIF3D suppresses cell proliferation in the ovarian tumour cell lines CAOV-3 and SKOV-3. Flow cytometry revealed that cells were arrested at the G2/M phase of the cell cycle and that cyclin-dependent kinase 1 was also altered after EIF3D silencing. The results presented here demonstrate that EIF3D may play an important role in the occurrence and development of ovarian cancer.
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Affiliation(s)
- Yaying Lin
- Department of Gynecology Xinhua Hospital Shanghai Jiao Tong University School of Medicine China
| | - Rongrong Zhang
- Department of Gynecology Xinhua Hospital Shanghai Jiao Tong University School of Medicine China
| | - Ping Zhang
- Department of Gynecology Xinhua Hospital Shanghai Jiao Tong University School of Medicine China
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47
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Wagner S, Herrmannová A, Šikrová D, Valášek LS. Human eIF3b and eIF3a serve as the nucleation core for the assembly of eIF3 into two interconnected modules: the yeast-like core and the octamer. Nucleic Acids Res 2016; 44:10772-10788. [PMID: 27924037 PMCID: PMC5159561 DOI: 10.1093/nar/gkw972] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/07/2016] [Accepted: 10/11/2016] [Indexed: 12/05/2022] Open
Abstract
The 12-subunit mammalian eIF3 is the largest and most complex translation initiation factor and has been implicated in numerous steps of translation initiation, termination and ribosomal recycling. Imbalanced eIF3 expression levels are observed in various types of cancer and developmental disorders, but the consequences of altered eIF3 subunit expression on its overall structure and composition, and on translation in general, remain unclear. We present the first complete in vivo study monitoring the effects of RNAi knockdown of each subunit of human eIF3 on its function, subunit balance and integrity. We show that the eIF3b and octameric eIF3a subunits serve as the nucleation core around which other subunits assemble in an ordered way into two interconnected modules: the yeast-like core and the octamer, respectively. In the absence of eIF3b neither module forms in vivo, whereas eIF3d knock-down results in severe proliferation defects with no impact on eIF3 integrity. Disrupting the octamer produces an array of subcomplexes with potential roles in translational regulation. This study, outlining the mechanism of eIF3 assembly and illustrating how imbalanced expression of eIF3 subunits impacts the factor's overall expression profile, thus provides a comprehensive guide to the human eIF3 complex and to the relationship between eIF3 misregulation and cancer.
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Affiliation(s)
- Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague, 142 20, the Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague, 142 20, the Czech Republic
| | - Darina Šikrová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague, 142 20, the Czech Republic
| | - Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague, 142 20, the Czech Republic
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48
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A Transcript-Specific eIF3 Complex Mediates Global Translational Control of Energy Metabolism. Cell Rep 2016; 16:1891-902. [PMID: 27477275 DOI: 10.1016/j.celrep.2016.07.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 05/19/2016] [Accepted: 07/03/2016] [Indexed: 01/20/2023] Open
Abstract
The multi-subunit eukaryotic translation initiation factor eIF3 is thought to assist in the recruitment of ribosomes to mRNA. The expression of eIF3 subunits is frequently disrupted in human cancers, but the specific roles of individual subunits in mRNA translation and cancer remain elusive. Using global transcriptomic, proteomic, and metabolomic profiling, we found a striking failure of Schizosaccharomyces pombe cells lacking eIF3e and eIF3d to synthesize components of the mitochondrial electron transport chain, leading to a defect in respiration, endogenous oxidative stress, and premature aging. Energy balance was maintained, however, by a switch to glycolysis with increased glucose uptake, upregulation of glycolytic enzymes, and strict dependence on a fermentable carbon source. This metabolic regulatory function appears to be conserved in human cells where eIF3e binds metabolic mRNAs and promotes their translation. Thus, via its eIF3d-eIF3e module, eIF3 orchestrates an mRNA-specific translational mechanism controlling energy metabolism that may be disrupted in cancer.
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49
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Assembly of eIF3 Mediated by Mutually Dependent Subunit Insertion. Structure 2016; 24:886-96. [PMID: 27210288 DOI: 10.1016/j.str.2016.02.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 02/19/2016] [Accepted: 02/21/2016] [Indexed: 02/05/2023]
Abstract
Eukaryotic initiation factor 3 (eIF3), an essential multi-protein complex involved in translation initiation, is composed of 12 tightly associated subunits in humans. While the overall structure of eIF3 is known, the mechanism of its assembly and structural consequences of dysregulation of eIF3 subunit expression seen in many cancers is largely unknown. Here we show that subunits in eIF3 assemble into eIF3 in an interdependent manner. Assembly of eIF3 is governed primarily by formation of a helical bundle, composed of helices extending C-terminally from PCI-MPN domains in eight subunits. We propose that, while the minimal subcomplex of human-like eIF3 functional for translation initiation in cells consists of subunits a, b, c, f, g, i, and m, numerous other eIF3 subcomplexes exist under circumstances of subunit over- or underexpression. Thus, eIF3 subcomplexes formed or "released" due to dysregulated subunit expression may be determining factors contributing to eIF3-related cancers.
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50
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Toompuu M, Kärblane K, Pata P, Truve E, Sarmiento C. ABCE1 is essential for S phase progression in human cells. Cell Cycle 2016; 15:1234-47. [PMID: 26985706 DOI: 10.1080/15384101.2016.1160972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
ABCE1 is a highly conserved protein universally present in eukaryotes and archaea, which is crucial for the viability of different organisms. First identified as RNase L inhibitor, ABCE1 is currently recognized as an essential translation factor involved in several stages of eukaryotic translation and ribosome biogenesis. The nature of vital functions of ABCE1, however, remains unexplained. Here, we study the role of ABCE1 in human cell proliferation and its possible connection to translation. We show that ABCE1 depletion by siRNA results in a decreased rate of cell growth due to accumulation of cells in S phase, which is accompanied by inefficient DNA synthesis and reduced histone mRNA and protein levels. We infer that in addition to the role in general translation, ABCE1 is involved in histone biosynthesis and DNA replication and therefore is essential for normal S phase progression. In addition, we analyze whether ABCE1 is implicated in transcript-specific translation via its association with the eIF3 complex subunits known to control the synthesis of cell proliferation-related proteins. The expression levels of a few such targets regulated by eIF3A, however, were not consistently affected by ABCE1 depletion.
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Affiliation(s)
- Marina Toompuu
- a Department of Gene Technology , Tallinn University of Technology , Tallinn , Estonia
| | - Kairi Kärblane
- a Department of Gene Technology , Tallinn University of Technology , Tallinn , Estonia
| | - Pille Pata
- a Department of Gene Technology , Tallinn University of Technology , Tallinn , Estonia
| | - Erkki Truve
- a Department of Gene Technology , Tallinn University of Technology , Tallinn , Estonia
| | - Cecilia Sarmiento
- a Department of Gene Technology , Tallinn University of Technology , Tallinn , Estonia
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