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Goh AR, Kim YN, Oh JH, Choi SK. A Novel Inhibitor of Translation Initiation Factor eIF5B in Saccharomyces cerevisiae. J Microbiol Biotechnol 2024; 34:1-10. [PMID: 38755008 DOI: 10.4014/jmb.2404.04015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 04/24/2024] [Accepted: 05/03/2024] [Indexed: 05/18/2024]
Abstract
The eukaryotic translation initiation factor eIF5B is a bacterial IF2 ortholog that plays an important role in ribosome joining and stabilization of the initiator tRNA on the AUG start codon during the initiation of translation. We identified the fluorophenyl oxazole derivative 2,2-dibromo-1-(2-(4-fluorophenyl)benzo[d]oxazol-5-yl)ethanone quinolinol as an inhibitor of fungal protein synthesis using an in vitro translation assay in a fungal system. Mutants resistant to this compound were isolated in Saccharomyces cerevisiae and were demonstrated to contain amino acid substitutions in eIF5B that conferred the resistance. These results suggest that eIF5B is a target of potential antifungal compound and that mutation of eIF5B can confer resistance. Subsequent identification of 16 other mutants revealed that primary mutations clustered mainly on domain 2 of eIF5B and secondarily mainly on domain 4. Domain 2 has been implicated in the interaction with the small ribosomal subunit during initiation of translation. The tested translation inhibitor could act by weakening the functional contact between eIF5B and the ribosome complex. This data provides the basis for the development of a new family of antifungals.
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Affiliation(s)
- Ah-Ra Goh
- Department of Biomedical Sciences, Sunchon National University, Sunchon 57922, Republic of Korea
| | - Yi-Na Kim
- Department of Biomedical Sciences, Sunchon National University, Sunchon 57922, Republic of Korea
| | - Jae Hyeun Oh
- Department of Biomedical Sciences, Sunchon National University, Sunchon 57922, Republic of Korea
| | - Sang Ki Choi
- Department of Biomedical Sciences, Sunchon National University, Sunchon 57922, Republic of Korea
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2
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Ando R, Ishikawa Y, Kamada Y, Izawa S. Contribution of the yeast bi-chaperone system in the restoration of the RNA helicase Ded1 and translational activity under severe ethanol stress. J Biol Chem 2023; 299:105472. [PMID: 37979914 PMCID: PMC10746526 DOI: 10.1016/j.jbc.2023.105472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/20/2023] Open
Abstract
Preexposure to mild stress often improves cellular tolerance to subsequent severe stress. Severe ethanol stress (10% v/v) causes persistent and pronounced translation repression in Saccharomyces cerevisiae. However, it remains unclear whether preexposure to mild stress can mitigate translation repression in yeast cells under severe ethanol stress. We found that the translational activity of yeast cells pretreated with 6% (v/v) ethanol was initially significantly repressed under subsequent 10% ethanol but was then gradually restored even under severe ethanol stress. We also found that 10% ethanol caused the aggregation of Ded1, which plays a key role in translation initiation as a DEAD-box RNA helicase. Pretreatment with 6% ethanol led to the gradual disaggregation of Ded1 under subsequent 10% ethanol treatment in wild-type cells but not in fes1Δhsp104Δ cells, which are deficient in Hsp104 with significantly reduced capacity for Hsp70. Hsp104 and Hsp70 are key components of the bi-chaperone system that play a role in yeast protein quality control. fes1Δhsp104Δ cells did not restore translational activity under 10% ethanol, even after pretreatment with 6% ethanol. These results indicate that the regeneration of Ded1 through the bi-chaperone system leads to the gradual restoration of translational activity under continuous severe stress. This study provides new insights into the acquired tolerance of yeast cells to severe ethanol stress and the resilience of their translational activity.
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Affiliation(s)
- Ryoko Ando
- Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
| | - Yu Ishikawa
- Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
| | | | - Shingo Izawa
- Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan.
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3
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Mourenets L, Pushin A, Timerbaev V, Khmelnitskaya T, Gribkov E, Andreev N, Dolgov S. Effect of Gene Silencing of Translation Initiation Factors eIF(iso)4G and eIF(iso)4E on Sour Cherry Rootstock Resistance to Sharka Disease. Int J Mol Sci 2022; 24:ijms24010360. [PMID: 36613806 PMCID: PMC9820581 DOI: 10.3390/ijms24010360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
Sharka disease, caused by the Plum pox virus (PPV), is one of the most harmful, quarantine viral diseases that affect stone fruit crops. The absence of natural resistance to the virus in stone fruits has become a decisive factor for the use of genetic transformation methods to obtain stable forms. The eIF(iso)4G and eIF(iso)4E genes encode translation initiation factors used in the PPV life cycle. In the presented study, the effect of silencing these genes using the RNA interference method on the resistance of sour cherry rootstock 146-2 plants (Prunus pumila L. x Prunus tomentosa Thunb) to the sharka disease was studied. Two vectors have been created for the genetic transformation of plants, with self-complementary sequences of the eIF(iso)4G and eIF(iso)4E gene fragments. The hairpin expression cassette contains a strong promoter of the peach ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) gene, as well as an intron and terminator of the same gene. We used the pMF1 vector containing recombinase R and a codA-nptII gene which makes it possible to obtain intragenic marker-free plants. A successful genetic transformation was carried out by the AGL0 strain of A. tumefaciens. Whole leaves of shoots cultivated in vitro were used as a source of explants. Eight independent transgenic lines of rootstock 146-2 were obtained in experiments (sixlines with a hairpin to the eIF(iso)4G gene and two lines with a hairpin to the eIF(iso)4E gene). Their status was confirmed by the PCR and Southern blotting. The obtained plants were acclimatized in a greenhouse. The silencing of the eIF(iso)4G and eIF(iso)4E genes in transgenic plants was confirmed by the quantitative PCR. The presence of specific small interfering (si) RNAs was confirmed by the method of Northern blotting. Plants of all transgenic rootstock lines were infected with PPV by the method of grafting with infected buds. Resistance to the PPV infection of the obtained transgenic plants was carried out by using an enzyme immunoassay. The ELISA results showed that silencing the eIF(iso)4G gene did not lead to increased resistance while silencing the eIF(iso)4E factor gene led to increased resistance to the PPV, and the one line's plants showed no signs of infection for two years after infecting. The work demonstrates a (promising) approach in which the creation of stone cultures resistant to the plum pox virus can be achieved by suppressing the genes of translation initiation factors in clonal rootstocks.
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Affiliation(s)
- Lilia Mourenets
- The Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
- Nikita Botanical Gardens — National Scientific Centre, Russian Academy of Sciences, 298648 Yalta, Russia
| | - Alexander Pushin
- The Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, 127550 Moscow, Russia
| | - Vadim Timerbaev
- The Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
- Nikita Botanical Gardens — National Scientific Centre, Russian Academy of Sciences, 298648 Yalta, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, 127550 Moscow, Russia
| | - Tatyana Khmelnitskaya
- The Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Eduard Gribkov
- Biological Institute, The National Research Tomsk State University, 634050 Tomsk, Russia
| | - Nikita Andreev
- Biological Institute, The National Research Tomsk State University, 634050 Tomsk, Russia
| | - Sergey Dolgov
- The Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
- Nikita Botanical Gardens — National Scientific Centre, Russian Academy of Sciences, 298648 Yalta, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, 127550 Moscow, Russia
- Correspondence: ; Tel.: +7-4-96-773-1779
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Zhang L, Zhang Y, Zhang S, Qiu L, Zhang Y, Zhou Y, Han J, Xie J. Translational Regulation by eIFs and RNA Modifications in Cancer. Genes (Basel) 2022; 13:2050. [PMID: 36360287 PMCID: PMC9690228 DOI: 10.3390/genes13112050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/25/2022] [Accepted: 11/04/2022] [Indexed: 11/04/2023] Open
Abstract
Translation is a fundamental process in all living organisms that involves the decoding of genetic information in mRNA by ribosomes and translation factors. The dysregulation of mRNA translation is a common feature of tumorigenesis. Protein expression reflects the total outcome of multiple regulatory mechanisms that change the metabolism of mRNA pathways from synthesis to degradation. Accumulated evidence has clarified the role of an increasing amount of mRNA modifications at each phase of the pathway, resulting in translational output. Translation machinery is directly affected by mRNA modifications, influencing translation initiation, elongation, and termination or altering mRNA abundance and subcellular localization. In this review, we focus on the translation initiation factors associated with cancer as well as several important RNA modifications, for which we describe their association with cancer.
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Affiliation(s)
- Linzhu Zhang
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- The Third People’s Hospital of Chengdu, Clinical College of Southwest Jiao Tong University, Chengdu 610014, China
| | - Yaguang Zhang
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Su Zhang
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Lei Qiu
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yang Zhang
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Ying Zhou
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Junhong Han
- State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-Related Molecular Network and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jiang Xie
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- The Third People’s Hospital of Chengdu, Clinical College of Southwest Jiao Tong University, Chengdu 610014, China
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Zhang M, Liu Y, Shi L, Fang L, Xu L, Cao Y. Neural stemness unifies cell tumorigenicity and pluripotent differentiation potential. J Biol Chem 2022; 298:102106. [PMID: 35671824 PMCID: PMC9254501 DOI: 10.1016/j.jbc.2022.102106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022] Open
Abstract
Neural stemness is suggested to be the ground state of tumorigenicity and pluripotent differentiation potential. However, the relationship between these cell properties is unclear. Here, by disrupting the neural regulatory network in neural stem and cancer cells and by serial transplantation of cancer cells, we show that tumorigenicity and pluripotent differentiation potential are coupled cell properties unified by neural stemness. We show that loss of neural stemness via inhibition of SETDB1, an oncoprotein with enriched expression in embryonic neural cells during vertebrate embryogenesis, led to neuronal differentiation with reduced tumorigenicity and pluripotent differentiation potential in neural stem and cancer cells, whereas enhancement of neural stemness by SETDB1 overexpression caused the opposite effects. SETDB1 maintains a regulatory network comprising proteins involved in developmental programs and basic cellular functional machineries, including epigenetic modifications (EZH2), ribosome biogenesis (RPS3), translation initiation (EIF4G), and spliceosome assembly (SF3B1); all of these proteins are enriched in embryonic neural cells and play active roles in cancers. In addition, SETDB1 represses the transcription of genes promoting differentiation and cell cycle and growth arrest. Serial transplantation of cancer cells showed that neural stemness, tumorigenicity, and pluripotent differentiation potential were simultaneously enhanced; these effects were accompanied by increased expression of proteins involved in developmental programs and basic machineries, including SETDB1 and the abovementioned proteins, as well as by increased alternative splicing events. These results indicate that basic machineries work together to define a highly proliferative state with pluripotent differentiation potential and also suggest that neural stemness unifies tumorigenicity and differentiation potential.
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Affiliation(s)
- Min Zhang
- Shenzhen Research Institute of Nanjing University, Shenzhen, China; MOE Key Laboratory of Model Animals for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center of Medical School
| | - Yang Liu
- Shenzhen Research Institute of Nanjing University, Shenzhen, China; MOE Key Laboratory of Model Animals for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center of Medical School
| | - Lihua Shi
- MOE Key Laboratory of Model Animals for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center of Medical School
| | - Lei Fang
- Jiangsu Key Laboratory of Molecular Medicine of Medical School, Nanjing University, Nanjing, China
| | - Liyang Xu
- MOE Key Laboratory of Model Animals for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center of Medical School
| | - Ying Cao
- Shenzhen Research Institute of Nanjing University, Shenzhen, China; MOE Key Laboratory of Model Animals for Disease Study and State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center of Medical School.
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Vanselow S, Neumann-Arnold L, Wojciech-Moock F, Seufert W. Stepwise assembly of the eukaryotic translation initiation factor 2 (eIF2) complex. J Biol Chem 2022;:101583. [PMID: 35031321 DOI: 10.1016/j.jbc.2022.101583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/02/2022] [Accepted: 01/04/2022] [Indexed: 11/22/2022] Open
Abstract
The eukaryotic translation initiation factor 2 (eIF2) has key functions in the initiation step of protein synthesis. eIF2 guides the initiator tRNA to the ribosome, participates in scanning of the mRNA molecule, supports selection of the start codon, and modulates the translation of mRNAs in response to stress. eIF2 comprises a heterotrimeric complex whose assembly depends on the ATP-grasp protein Cdc123. Mutations of the eIF2γ subunit that compromise eIF2 complex formation cause severe neurological disease in humans. To this date, however, details about the assembly mechanism, step order, and the individual functions of eIF2 subunits remain unclear. Here, we quantified assembly intermediates and studied the behavior of various binding site mutants in budding yeast. Based on these data, we present a model in which a Cdc123-mediated conformational change in eIF2γ exposes binding sites for eIF2α and -β subunits. Contrary to an earlier hypothesis, we found that the associations of eIF2α and -β with the γ-subunit are independent of each other, but the resulting heterodimers are non-functional and fail to bind the guanosine exchange factor eIF2B. In addition, levels of eIF2α influence the rate of eIF2 assembly. By binding to eIF2γ, eIF2α displaces Cdc123 and thereby completes the assembly process. Experiments in human cell culture indicate that the mechanism of eIF2 assembly is conserved between yeast and humans. This study sheds light on an essential step in eukaryotic translation initiation, the dysfunction of which is linked to human disease.
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Barrado-Gil L, Del Puerto A, Muñoz-Moreno R, Galindo I, Cuesta-Geijo MÁ, Urquiza J, Nistal-Villán E, Maluquer de Motes C, Alonso C. African Swine Fever Virus Ubiquitin-Conjugating Enzyme Interacts With Host Translation Machinery to Regulate the Host Protein Synthesis. Front Microbiol 2020; 11:622907. [PMID: 33384682 PMCID: PMC7771050 DOI: 10.3389/fmicb.2020.622907] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 11/23/2020] [Indexed: 01/25/2023] Open
Abstract
African Swine Fever virus (ASFV) causes one of the most relevant emerging diseases affecting swine, now extended through three continents. The virus has a large coding capacity to deploy an arsenal of molecules antagonizing the host functions. In the present work, we have studied the only known E2 viral-conjugating enzyme, UBCv1 that is encoded by the I215L gene of ASFV. UBCv1 was expressed as an early expression protein that accumulates throughout the course of infection. This versatile protein, bound several types of polyubiquitin chains and its catalytic domain was required for enzymatic activity. High throughput mass spectrometry analysis in combination with a screening of an alveolar macrophage library was used to identify and characterize novel UBCv1-host interactors. The analysis revealed interaction with the 40S ribosomal protein RPS23, the cap-dependent translation machinery initiation factor eIF4E, and the E3 ubiquitin ligase Cullin 4B. Our data show that during ASFV infection, UBCv1 was able to bind to eIF4E, independent from the cap-dependent complex. Our results provide novel insights into the function of the viral UBCv1 in hijacking cellular components that impact the mTORC signaling pathway, the regulation of the host translation machinery, and the cellular protein expression during the ASFV lifecycle.
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Affiliation(s)
- Lucía Barrado-Gil
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Ana Del Puerto
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Raquel Muñoz-Moreno
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Inmaculada Galindo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Miguel Ángel Cuesta-Geijo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Jesús Urquiza
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Estanislao Nistal-Villán
- Microbiology Section, Departamento Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Instituto de Medicina Molecular Aplicada (IMMA), Madrid, Spain
| | - Carlos Maluquer de Motes
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom
| | - Covadonga Alonso
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
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Fedele AO, Carraro V, Xie J, Averous J, Proud CG. Cyclosporin A but not FK506 activates the integrated stress response in human cells. J Biol Chem 2020; 295:15134-15143. [PMID: 32843478 DOI: 10.1074/jbc.ra120.014531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/28/2020] [Indexed: 11/06/2022] Open
Abstract
Cyclosporin A (CsA) and tacrolimus (FK506) are valuable immunosuppressants for a range of clinical settings, including (but not limited to) organ transplantation and the treatment of autoimmune diseases. They function by inhibiting the activity of the Ca2+/calmodulin-dependent phosphatase calcineurin toward nuclear factor of activated T-cells (NF-AT) in T-lymphocytes. However, use of CsA is associated with more serious side effects and worse clinical outcomes than FK506. Here we show that CsA, but not FK506, causes activation of the integrated stress response (ISR), an event which is normally an acute reaction to various types of intracellular insults, such as nutrient deficiency or endoplasmic reticulum stress. These effects of CsA involve at least two of the stress-activated protein kinases (GCN2 and PERK) that act on the translational machinery to slow down protein synthesis via phosphorylation of the eukaryotic initiation factor (eIF) 2α and thereby induce the ISR. These actions of CsA likely contribute to the adverse effects associated with its clinical application.
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Affiliation(s)
- Anthony O Fedele
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health & Medical Research Institute, North Terrace Campus, Adelaide, Australia
| | - Valérie Carraro
- INRAE Unité de Nutrition Humaine, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Jianling Xie
- Lifelong Health Theme, South Australian Health & Medical Research Institute, North Terrace Campus, Adelaide, Australia
| | - Julien Averous
- INRAE Unité de Nutrition Humaine, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Christopher G Proud
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health & Medical Research Institute, North Terrace Campus, Adelaide, Australia; Lifelong Health Theme, South Australian Health & Medical Research Institute, North Terrace Campus, Adelaide, Australia; School of Biological Sciences, University of Adelaide, North Terrace Campus, Adelaide, Australia.
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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Udagawa H, Koga K, Shinjo A, Kitashiba H, Takakura Y. Reduced susceptibility to a tobacco bushy top virus Malawi isolate by loss of function in host eIF(iso)4E genes. Breed Sci 2020; 70:313-320. [PMID: 32714053 PMCID: PMC7372031 DOI: 10.1270/jsbbs.19135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/25/2019] [Indexed: 05/23/2023]
Abstract
Tobacco bushy top disease (TBTD) is a viral disease of tobacco (Nicotiana tabacum L.) caused by mixed infection of Tobacco bushy top virus or Ethiopian tobacco bushy top virus and a helper virus. Despite its damage to tobacco, practical genetic resources for disease resistance have not been found. Here, we report that a mutation of tobacco eIF(iso)4E genes (eIF(iso)4E-S and eIF(iso)4E-T), which encode eukaryotic translation initiation factors, confers resistance (reduced susceptibility) to TBTD caused by a virus from Malawi (designated as tobacco bushy top virus Malawi isolate, TBTV-MW). RNAi lines in which eIF(iso)4E genes were silenced showed reduced susceptibility to TBTV-MW. We also tested chemically-induced single (eIF(iso)4E-S or eIF(iso)4E-T) and double (eIF(iso)4E-S and eIF(iso)4E-T) nonsense mutants for resistance to TBTV-MW. Suppression of eIF(iso)4E-S showed reduced susceptibility, and the resistance of the double mutant tended to be even stronger. eIF(iso)4E mutants also showed reduced susceptibility to TBTV-MW transmitted by aphids. To the best of our knowledge, the eIF(iso)4E-S mutant is the first genetic resource for TBTD resistance breeding in tobacco.
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Affiliation(s)
- Hisashi Udagawa
- Leaf Tobacco Research Center, Japan Tobacco, Inc., 1900, Idei, Oyama, Tochigi 323-0808, Japan
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - Kazuharu Koga
- Leaf Tobacco Research Center, Japan Tobacco, Inc., 1900, Idei, Oyama, Tochigi 323-0808, Japan
| | - Akira Shinjo
- Leaf Tobacco Research Center, Japan Tobacco, Inc., 1900, Idei, Oyama, Tochigi 323-0808, Japan
| | - Hiroyasu Kitashiba
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - Yoshimitsu Takakura
- Leaf Tobacco Research Center, Japan Tobacco, Inc., 1900, Idei, Oyama, Tochigi 323-0808, Japan
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Godet AC, David F, Hantelys F, Tatin F, Lacazette E, Garmy-Susini B, Prats AC. IRES Trans-Acting Factors, Key Actors of the Stress Response. Int J Mol Sci 2019; 20:ijms20040924. [PMID: 30791615 PMCID: PMC6412753 DOI: 10.3390/ijms20040924] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 12/16/2022] Open
Abstract
The cellular stress response corresponds to the molecular changes that a cell undergoes in response to various environmental stimuli. It induces drastic changes in the regulation of gene expression at transcriptional and posttranscriptional levels. Actually, translation is strongly affected with a blockade of the classical cap-dependent mechanism, whereas alternative mechanisms are activated to support the translation of specific mRNAs. A major mechanism involved in stress-activated translation is the internal ribosome entry site (IRES)-driven initiation. IRESs, first discovered in viral mRNAs, are present in cellular mRNAs coding for master regulators of cell responses, whose expression must be tightly controlled. IRESs allow the translation of these mRNAs in response to different stresses, including DNA damage, amino-acid starvation, hypoxia or endoplasmic reticulum stress, as well as to physiological stimuli such as cell differentiation or synapse network formation. Most IRESs are regulated by IRES trans-acting factor (ITAFs), exerting their action by at least nine different mechanisms. This review presents the history of viral and cellular IRES discovery as well as an update of the reported ITAFs regulating cellular mRNA translation and of their different mechanisms of action. The impact of ITAFs on the coordinated expression of mRNA families and consequences in cell physiology and diseases are also highlighted.
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Affiliation(s)
- Anne-Claire Godet
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Florian David
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Fransky Hantelys
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Florence Tatin
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Eric Lacazette
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Barbara Garmy-Susini
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
| | - Anne-Catherine Prats
- UMR 1048-I2MC, Inserm, Université de Toulouse, UT3, 31432 Toulouse cedex 4, France.
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12
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Abstract
This paper is in recognition of the 100th birthday of Dr. Herbert Tabor, a true pioneer in the polyamine field for over 70 years, who served as the editor-in-chief of the Journal of Biological Chemistry from 1971 to 2010. We review current knowledge of MYC proteins (c-MYC, MYCN, and MYCL) and focus on ornithine decarboxylase 1 (ODC1), an important bona fide gene target of MYC, which encodes the sentinel, rate-limiting enzyme in polyamine biosynthesis. Although notable advances have been made in designing inhibitors against the "undruggable" MYCs, their downstream targets and pathways are currently the main avenue for therapeutic anticancer interventions. To this end, the MYC-ODC axis presents an attractive target for managing cancers such as neuroblastoma, a pediatric malignancy in which MYCN gene amplification correlates with poor prognosis and high-risk disease. ODC and polyamine levels are often up-regulated and contribute to tumor hyperproliferation, especially of MYC-driven cancers. We therefore had proposed to repurpose α-difluoromethylornithine (DFMO), an FDA-approved, orally available ODC inhibitor, for management of neuroblastoma, and this intervention is now being pursued in several clinical trials. We discuss the regulation of ODC and polyamines, which besides their well-known interactions with DNA and tRNA/rRNA, are involved in regulating RNA transcription and translation, ribosome function, proteasomal degradation, the circadian clock, and immunity, events that are also controlled by MYC proteins.
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Affiliation(s)
- André S Bachmann
- From the Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan 49503 and
| | - Dirk Geerts
- the Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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13
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Patrick RM, Lee JCH, Teetsel JRJ, Yang SH, Choy GS, Browning KS. Discovery and characterization of conserved binding of eIF4E 1 (CBE1), a eukaryotic translation initiation factor 4E-binding plant protein. J Biol Chem 2018; 293:17240-17247. [PMID: 30213859 DOI: 10.1074/jbc.ra118.003945] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/08/2018] [Indexed: 12/23/2022] Open
Abstract
In many eukaryotes, translation initiation is regulated by proteins that bind to the mRNA cap-binding protein eukaryotic translation initiation factor 4E (eIF4E). These proteins commonly prevent association of eIF4E with eIF4G or form repressive messenger ribonucleoproteins that exclude the translation machinery. Such gene-regulatory mechanisms in plants, and even the presence of eIF4E-interacting proteins other than eIF4G (and the plant-specific isoform eIFiso4G, which binds eIFiso4E), are unknown. Here, we report the discovery of a plant-specific protein, conserved binding of eIF4E 1 (CBE1). We found that CBE1 has an evolutionarily conserved eIF4E-binding motif in its N-terminal domain and binds eIF4E or eIFiso4E in vitro CBE1 thereby forms cap-binding complexes and is an eIF4E-dependent constituent of these complexes in vivo Of note, plant mutants lacking CBE1 exhibited dysregulation of cell cycle-related transcripts and accumulated higher levels of mRNAs encoding proteins involved in mitosis than did WT plants. Our findings indicate that CBE1 is a plant protein that can form mRNA cap-binding complexes having the potential for regulating gene expression. Because mammalian translation factors are known regulators of cell cycle progression, we propose that CBE1 may represent such first translation factor-associated plant-specific cell cycle regulator.
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Affiliation(s)
- Ryan M Patrick
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Jessica C H Lee
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Jade R J Teetsel
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Soo-Hyun Yang
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Grace S Choy
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Karen S Browning
- From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
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14
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Murakami R, Singh CR, Morris J, Tang L, Harmon I, Takasu A, Miyoshi T, Ito K, Asano K, Uchiumi T. The Interaction between the Ribosomal Stalk Proteins and Translation Initiation Factor 5B Promotes Translation Initiation. Mol Cell Biol 2018; 38:e00067-18. [PMID: 29844065 DOI: 10.1128/MCB.00067-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/14/2018] [Indexed: 01/01/2023] Open
Abstract
Ribosomal stalk proteins recruit translation elongation GTPases to the factor-binding center of the ribosome. Initiation factor 5B (eIF5B in eukaryotes and aIF5B in archaea) is a universally conserved GTPase that promotes the joining of the large and small ribosomal subunits during translation initiation. Here we show that aIF5B binds to the C-terminal tail of the stalk protein. In the cocrystal structure, the interaction occurs between the hydrophobic amino acids of the stalk C-terminal tail and a small hydrophobic pocket on the surface of the GTP-binding domain (domain I) of aIF5B. A substitution mutation altering the hydrophobic pocket of yeast eIF5B resulted in a marked reduction in ribosome-dependent eIF5B GTPase activity in vitro In yeast cells, the eIF5B mutation affected growth and impaired GCN4 expression during amino acid starvation via a defect in start site selection for the first upstream open reading frame in GCN4 mRNA, as observed with the eIF5B deletion mutant. The deletion of two of the four stalk proteins diminished polyribosome levels (indicating defective translation initiation) and starvation-induced GCN4 expression, both of which were suppressible by eIF5B overexpression. Thus, the mutual interaction between a/eIF5B and the ribosomal stalk plays an important role in subunit joining during translation initiation in vivo.
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15
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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16
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de Melo Neto OP, da Costa Lima TDC, Merlo KC, Romão TP, Rocha PO, Assis LA, Nascimento LM, Xavier CC, Rezende AM, Reis CRS, Papadopoulou B. Phosphorylation and interactions associated with the control of the Leishmania Poly-A Binding Protein 1 (PABP1) function during translation initiation. RNA Biol 2018; 15:739-755. [PMID: 29569995 DOI: 10.1080/15476286.2018.1445958] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Poly-A Binding Protein (PABP) is a conserved eukaryotic polypeptide involved in many aspects of mRNA metabolism. During translation initiation, PABP interacts with the translation initiation complex eIF4F and enhances the translation of polyadenylated mRNAs. Schematically, most PABPs can be divided into an N-terminal RNA-binding region, a non-conserved linker segment and the C-terminal MLLE domain. In pathogenic Leishmania protozoans, three PABP homologues have been identified, with the first one (PABP1) targeted by phosphorylation and shown to co-immunoprecipitate with an eIF4F-like complex (EIF4E4/EIF4G3) implicated in translation initiation. Here, PABP1 phosphorylation was shown to be linked to logarithmic cell growth, reminiscent of EIF4E4 phosphorylation, and coincides with polysomal association. Phosphorylation targets multiple serine-proline (SP) or threonine-proline (TP) residues within the PABP1 linker region. This is an essential protein, but phosphorylation is not needed for its association with polysomes or cell viability. Mutations which do impair PABP1 polysomal association and are required for viability do not prevent phosphorylation, although further mutations lead to a presumed inactive protein largely lacking phosphorylated isoforms. Co-immunoprecipitation experiments were carried out to investigate PABP1 function further, identifying several novel protein partners and the EIF4E4/EIF4G3 complex, but no other eIF4F-like complex or subunit. A novel, direct interaction between PABP1 and EIF4E4 was also investigated and found to be mediated by the PABP1 MLLE binding to PABP Interacting Motifs (PAM2) within the EIF4E4 N-terminus. The results shown here are consistent with phosphorylation of PABP1 being part of a novel pathway controlling its function and possibly translation in Leishmania.
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Affiliation(s)
| | | | - Kleison C Merlo
- a Instituto Aggeu Magalhães - FIOCRUZ , Recife , PE , Brazil
| | - Tatiany P Romão
- a Instituto Aggeu Magalhães - FIOCRUZ , Recife , PE , Brazil
| | | | - Ludmila A Assis
- a Instituto Aggeu Magalhães - FIOCRUZ , Recife , PE , Brazil
| | | | - Camila C Xavier
- a Instituto Aggeu Magalhães - FIOCRUZ , Recife , PE , Brazil
| | | | | | - Barbara Papadopoulou
- c CHU de Quebec Research Center and Department of Microbiology-Infectious Disease and Immunology , Laval University , Quebec , QC , Canada
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17
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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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18
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Zhao P, Liu Q, Miller WA, Goss DJ. Eukaryotic translation initiation factor 4G (eIF4G) coordinates interactions with eIF4A, eIF4B, and eIF4E in binding and translation of the barley yellow dwarf virus 3' cap-independent translation element (BTE). J Biol Chem 2017; 292:5921-5931. [PMID: 28242763 DOI: 10.1074/jbc.m116.764902] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/07/2017] [Indexed: 12/11/2022] Open
Abstract
Barley yellow dwarf virus RNA, lacking a 5' cap and a 3' poly(A) tail, contains a cap-independent translation element (BTE) in the 3'-untranslated region that interacts with host translation initiation factor eIF4G. To determine how eIF4G recruits the mRNA, three eIF4G deletion mutants were constructed: (i) eIF4G601-1196, containing amino acids 601-1196, including the putative BTE-binding region, and binding domains for eIF4E, eIF4A, and eIF4B; (ii) eIF4G601-1488, which contains an additional C-terminal eIF4A-binding domain; and (iii) eIF4G742-1196, which lacks the eIF4E-binding site. eIF4G601-1196 binds BTE tightly and supports efficient translation. The helicase complex, consisting of eIF4A, eIF4B, and ATP, stimulated BTE binding with eIF4G601-1196 but not eIF4G601-1488, suggesting that the eIF4A binding domains may serve a regulatory role, with the C-terminal binding site having negative effects. eIF4E binding to eIF4G601-1196 induced a conformational change, significantly increasing the binding affinity to BTE. A comparison of the binding of eIF4G deletion mutants with BTEs containing mutations showed a general correlation between binding affinity and ability to facilitate translation. In summary, these results reveal a new role for the helicase complex in 3' cap-independent translation element-mediated translation and show that the functional core domain of eIF4G plus an adjacent probable RNA-binding domain mediate translation initiation.
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Affiliation(s)
- Pei Zhao
- From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and.,the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and
| | - Qiao Liu
- From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and.,the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and
| | - W Allen Miller
- the Plant Pathology & Microbiology and.,Biochemistry, Biophysics & Molecular Biology Departments, Iowa State University, Ames, Iowa 50011
| | - Dixie J Goss
- From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and .,the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and
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19
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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Mohammad S, Wolfe LA, Stöbe P, Biskup S, Wainwright MS, Melin-Aldana H, Malladi P, Muenke M, Gahl WA, Whitington PF. Infantile Cirrhosis, Growth Impairment, and Neurodevelopmental Anomalies Associated with Deficiency of PPP1R15B. J Pediatr 2016; 179:144-149.e2. [PMID: 27640355 DOI: 10.1016/j.jpeds.2016.08.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/29/2016] [Accepted: 08/10/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVE To assess the utility of whole-exome sequencing (WES) in a sibling pair with undetermined liver disease and describe the phenotype associated with mutations discovered therein. STUDY DESIGN Next-generation WES was performed on 2 siblings (S1 and S2) who were born to nonconsanguineous parents of European extraction. Both siblings developed cirrhosis of indeterminate etiology and required liver transplantation; S1 at 7 months and S2 at 22 months. RESULTS Sequencing of germline DNA identified compound heterozygous mutations in PPP1R15B resulting in increased levels of phosphorylated eukaryotic translation initiation factor 2α. CONCLUSIONS The first demonstration of PPP1R15B associated with liver disease expands the phenotypic spectrum of PPP1R15B related diseases. Our findings validate the application of WES in the diagnosis of children with undetermined liver disease. Understanding the genetic basis of liver disease may allow the development of targeted therapies for treatment and adequate counseling of families.
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Affiliation(s)
- Saeed Mohammad
- Division of Gastroenterology, Department of Pediatrics, Feinberg School of Medicine of Northwestern University and Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, IL
| | - Lynne A Wolfe
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, National Institutes of Health, Bethesda, MD
| | - Petra Stöbe
- Center for Genomics and Transcriptomics, Tuebingen, Germany
| | - Saskia Biskup
- Center for Genomics and Transcriptomics, Tuebingen, Germany
| | - Mark S Wainwright
- Division of Neurology, Department of Pediatrics, Feinberg School of Medicine of Northwestern University and Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL
| | - Hector Melin-Aldana
- Department of Pathology, Feinberg School of Medicine of Northwestern University and Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, IL
| | - Padmini Malladi
- Division of Gastroenterology, Department of Pediatrics, Feinberg School of Medicine of Northwestern University and Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, IL
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda MD
| | - William A Gahl
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Peter F Whitington
- Division of Gastroenterology, Department of Pediatrics, Feinberg School of Medicine of Northwestern University and Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, IL
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21
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Vaysse C, Philippe C, Martineau Y, Quelen C, Hieblot C, Renaud C, Nicaise Y, Desquesnes A, Pannese M, Filleron T, Escourrou G, Lawson M, Rintoul RC, Delisle MB, Pyronnet S, Brousset P, Prats H, Touriol C. Key contribution of eIF4H-mediated translational control in tumor promotion. Oncotarget 2016; 6:39924-40. [PMID: 26498689 PMCID: PMC4741870 DOI: 10.18632/oncotarget.5442] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/03/2015] [Indexed: 02/06/2023] Open
Abstract
Dysregulated expression of translation initiation factors has been associated with carcinogenesis, but underlying mechanisms remains to be fully understood. Here we show that eIF4H (eukaryotic translation initiation factor 4H), an activator of the RNA helicase eIF4A, is overexpressed in lung carcinomas and predictive of response to chemotherapy. In lung cancer cells, depletion of eIF4H enhances sensitization to chemotherapy, decreases cell migration and inhibits tumor growth in vivo, in association with reduced translation of mRNA encoding cell-proliferation (c-Myc, cyclin D1) angiogenic (FGF-2) and anti-apoptotic factors (CIAP-1, BCL-xL). Conversely, each isoform of eIF4H acts as an oncogene in NIH3T3 cells by stimulating transformation, invasion, tumor growth and resistance to drug-induced apoptosis together with increased translation of IRES-containing or structured 5′UTR mRNAs. These results demonstrate that eIF4H plays a crucial role in translational control and can promote cellular transformation by preferentially regulating the translation of potent growth and survival factor mRNAs, indicating that eIF4H is a promising new molecular target for cancer therapy.
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Affiliation(s)
- Charlotte Vaysse
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Céline Philippe
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Yvan Martineau
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Cathy Quelen
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Corinne Hieblot
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Claire Renaud
- Department of Thoracic Surgery, Rangueil-Larrey Hospital, Toulouse, France
| | - Yvan Nicaise
- Department of Pathology, CHU Rangueil, Toulouse, France
| | | | | | - Thomas Filleron
- Clinical Trial Office, Cellule Biostatistique Institut Universitaire du Cancer Toulouse, Toulouse, France
| | - Ghislaine Escourrou
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Department of Pathology, CHU Rangueil, Toulouse, France
| | - Malcolm Lawson
- Department of Respiratory Medicine, Broomfield Hospital, Chelmsford, Essex, UK
| | - Robert C Rintoul
- Department of Thoracic Oncology, Papworth Hospital, Cambridge, UK
| | - Marie Bernadette Delisle
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Department of Pathology, CHU Rangueil, Toulouse, France
| | - Stéphane Pyronnet
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Pierre Brousset
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France.,Department of Pathology, Institut Universitaire du Cancer, Toulouse, France
| | - Hervé Prats
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
| | - Christian Touriol
- INSERM U1037, CRCT, Cancer Research Center of Toulouse, Toulouse, France.,Toulouse University, Paul Sabatier, Toulouse, France
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22
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Abstract
Synthesis of polypeptides from mRNA (translation) is a fundamental cellular process that is coordinated and catalyzed by a set of canonical ‘translation factors’. Surprisingly, the translation factors of Drosophila melanogaster have not yet been systematically identified, leading to inconsistencies in their nomenclature and shortcomings in functional (Gene Ontology, GO) annotations. Here, we describe the complete set of translation factors in D. melanogaster, applying nomenclature already in widespread use in other species, and revising their functional annotation. The collection comprises 43 initiation factors, 12 elongation factors, 3 release factors and 6 recycling factors, totaling 64 of which 55 are cytoplasmic and 9 are mitochondrial. We also provide an overview of notable findings and particular insights derived from Drosophila about these factors. This catalog, together with the incorporation of the improved nomenclature and GO annotation into FlyBase, will greatly facilitate access to information about the functional roles of these important proteins.
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Affiliation(s)
- Steven J Marygold
- a FlyBase, Department of Physiology , Development and Neuroscience, University of Cambridge , Cambridge , UK
| | - Helen Attrill
- a FlyBase, Department of Physiology , Development and Neuroscience, University of Cambridge , Cambridge , UK
| | - Paul Lasko
- b Department of Biology , McGill University , Bellini Life Sciences Complex, Montreal, Quebec , Canada
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Fujimura K, Choi S, Wyse M, Strnadel J, Wright T, Klemke R. Eukaryotic Translation Initiation Factor 5A (EIF5A) Regulates Pancreatic Cancer Metastasis by Modulating RhoA and Rho-associated Kinase (ROCK) Protein Expression Levels. J Biol Chem 2015; 290:29907-19. [PMID: 26483550 PMCID: PMC4706006 DOI: 10.1074/jbc.m115.687418] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/15/2015] [Indexed: 12/12/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with an overall survival rate of less than 5%. The poor patient outcome in PDAC is largely due to the high prevalence of systemic metastasis at the time of diagnosis and lack of effective therapeutics that target disseminated cells. The fact that the underlying mechanisms driving PDAC cell migration and dissemination are poorly understood have hindered drug development and compounded the lack of clinical success in this disease. Recent evidence indicates that mutational activation of K-Ras up-regulates eIF5A, a component of the cellular translational machinery that is critical for PDAC progression. However, the role of eIF5A in PDAC cell migration and metastasis has not been investigated. We report here that pharmacological inhibition or genetic knockdown of eIF5A reduces PDAC cell migration, invasion, and metastasis in vitro and in vivo. Proteomic profiling and bioinformatic analyses revealed that eIF5A controls an integrated network of cytoskeleton-regulatory proteins involved in cell migration. Functional interrogation of this network uncovered a critical RhoA/ROCK signaling node that operates downstream of eIF5A in invasive PDAC cells. Importantly, eIF5A mediates PDAC cell migration and invasion by modulating RhoA/ROCK protein expression levels. Together our findings implicate eIF5A as a cytoskeletal rheostat controlling RhoA/ROCK protein expression during PDAC cell migration and metastasis. Our findings also implicate the eIF5A/RhoA/ROCK module as a potential new therapeutic target to treat metastatic PDAC cells.
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Affiliation(s)
- Ken Fujimura
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Sunkyu Choi
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Meghan Wyse
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Jan Strnadel
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Tracy Wright
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Richard Klemke
- From the Department of Pathology, Moores Cancer Center, University of California, San Diego, La Jolla, California 92093
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24
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Kroczynska B, Rafidi RL, Majchrzak-Kita B, Kosciuczuk EM, Blyth GT, Jemielity J, Warminska Z, Saleiro D, Mehrotra S, Arslan AD, Fish EN, Platanias LC. Interferon γ (IFNγ) Signaling via Mechanistic Target of Rapamycin Complex 2 (mTORC2) and Regulatory Effects in the Generation of Type II Interferon Biological Responses. J Biol Chem 2015; 291:2389-96. [PMID: 26645692 DOI: 10.1074/jbc.m115.664995] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 01/22/2023] Open
Abstract
We provide evidence for a unique pathway engaged by the type II IFN receptor, involving mTORC2/AKT-mediated downstream regulation of mTORC1 and effectors. These events are required for formation of the eukaryotic translation initiation factor 4F complex (eIF4F) and initiation of mRNA translation of type II interferon-stimulated genes. Our studies establish that Rictor is essential for the generation of type II IFN-dependent antiviral and antiproliferative responses and that it controls the generation of type II IFN-suppressive effects on normal and malignant hematopoiesis. Together, our findings establish a central role for mTORC2 in IFNγ signaling and type II IFN responses.
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Affiliation(s)
- Barbara Kroczynska
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, the Department of Radiation Oncology, Northwestern University, Chicago, Illinois 60611
| | - Robert L Rafidi
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Beata Majchrzak-Kita
- the Toronto General Research Institute, University Health Network, and Department of Immunology, University of Toronto, Toronto, Ontario M5G 2MI, Canada
| | - Ewa M Kosciuczuk
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, the Division of Hematology-Oncology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
| | - Gavin T Blyth
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Jacek Jemielity
- the Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland, and
| | - Zofia Warminska
- the Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland, and the College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 02-089 Warsaw, Poland
| | - Diana Saleiro
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Swarna Mehrotra
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Ahmet Dirim Arslan
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Eleanor N Fish
- the Toronto General Research Institute, University Health Network, and Department of Immunology, University of Toronto, Toronto, Ontario M5G 2MI, Canada
| | - Leonidas C Platanias
- From the Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, the Division of Hematology-Oncology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612,
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25
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Schmidt C, Beilsten-Edmands V, Robinson CV. Insights into Eukaryotic Translation Initiation from Mass Spectrometry of Macromolecular Protein Assemblies. J Mol Biol 2015; 428:344-356. [PMID: 26497764 DOI: 10.1016/j.jmb.2015.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/28/2015] [Accepted: 10/14/2015] [Indexed: 02/05/2023]
Abstract
Translation initiation in eukaryotes requires the interplay of at least 10 initiation factors that interact at the different steps of this phase of gene expression. The interactions of initiation factors and related proteins are in general controlled by phosphorylation, which serves as a regulatory switch to turn protein translation on or off. The structures of initiation factors and a complete description of their post-translational modification (PTM) status are therefore required in order to fully understand these processes. In recent years, mass spectrometry has contributed considerably to provide this information and nowadays is proving to be indispensable when studying dynamic heterogeneous protein complexes such as the eukaryotic initiation factors. Herein, we highlight mass spectrometric approaches commonly applied to identify interacting subunits and their PTMs and the structural techniques that allow the architecture of protein complexes to be assessed. We present recent structural investigations of initiation factors and their interactions with other factors and with ribosomes and we assess the models generated. These models allow us to locate PTMs within initiation factor complexes and to highlight possible roles for phosphorylation sites in regulating interaction interfaces.
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Affiliation(s)
- Carla Schmidt
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
| | - Victoria Beilsten-Edmands
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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26
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Taymans JM, Nkiliza A, Chartier-Harlin MC. Deregulation of protein translation control, a potential game-changing hypothesis for Parkinson's disease pathogenesis. Trends Mol Med 2015; 21:466-72. [PMID: 26091824 DOI: 10.1016/j.molmed.2015.05.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/15/2015] [Accepted: 05/19/2015] [Indexed: 02/08/2023]
Abstract
Protein translation is one of the most fundamental and exquisitely controlled processes in biology, and is energetically demanding. The deregulation of this process is deleterious to cells, as demonstrated by several diseases caused by mutations in protein translation machinery. Emerging evidence now points to a role for protein translation in the pathogenesis of Parkinson's disease (PD); a debilitating neurodegenerative movement disorder. In this paper, we propose a hypothesis that protein translation machinery, PD-associated proteins and PD pathology are connected in a functional network linking cell survival to protein translation control. This hypothesis is a potential game changer in the field of the molecular pathogenesis of PD, with implications for the development of PD diagnostics and disease-modifying therapies.
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27
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Freire ER, Vashisht AA, Malvezzi AM, Zuberek J, Langousis G, Saada EA, Nascimento JDF, Stepinski J, Darzynkiewicz E, Hill K, De Melo Neto OP, Wohlschlegel JA, Sturm NR, Campbell DA. eIF4F-like complexes formed by cap-binding homolog TbEIF4E5 with TbEIF4G1 or TbEIF4G2 are implicated in post-transcriptional regulation in Trypanosoma brucei. RNA 2014; 20:1272-86. [PMID: 24962368 PMCID: PMC4105752 DOI: 10.1261/rna.045534.114] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/12/2014] [Indexed: 05/19/2023]
Abstract
Members of the eIF4E mRNA cap-binding family are involved in translation and the modulation of transcript availability in other systems as part of a three-component complex including eIF4G and eIF4A. The kinetoplastids possess four described eIF4E and five eIF4G homologs. We have identified two new eIF4E family proteins in Trypanosoma brucei, and define distinct complexes associated with the fifth member, TbEIF4E5. The cytosolic TbEIF4E5 protein binds cap 0 in vitro. TbEIF4E5 was found in association with two of the five TbEIF4Gs. TbIF4EG1 bound TbEIF4E5, a 47.5-kDa protein with two RNA-binding domains, and either the regulatory protein 14-3-3 II or a 117.5-kDa protein with guanylyltransferase and methyltransferase domains in a potentially dynamic interaction. The TbEIF4G2/TbEIF4E5 complex was associated with a 17.9-kDa hypothetical protein and both 14-3-3 variants I and II. Knockdown of TbEIF4E5 resulted in the loss of productive cell movement, as evidenced by the inability of the cells to remain in suspension in liquid culture and the loss of social motility on semisolid plating medium, as well as a minor reduction of translation. Cells appeared lethargic, as opposed to compromised in flagellar function per se. The minimal use of transcriptional control in kinetoplastids requires these organisms to implement downstream mechanisms to regulate gene expression, and the TbEIF4E5/TbEIF4G1/117.5-kDa complex in particular may be a key player in that process. We suggest that a pathway involved in cell motility is affected, directly or indirectly, by one of the TbEIF4E5 complexes.
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Affiliation(s)
- Eden R Freire
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Ajay A Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Amaranta M Malvezzi
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA Department of Microbiology, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco 50670-420, Brazil
| | - Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Gerasimos Langousis
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Edwin A Saada
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Janaína De F Nascimento
- Department of Microbiology, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco 50670-420, Brazil
| | - Janusz Stepinski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland Centre of New Technologies, University of Warsaw, 02-089 Warsaw, Poland
| | - Kent Hill
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Osvaldo P De Melo Neto
- Department of Microbiology, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco 50670-420, Brazil
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Nancy R Sturm
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - David A Campbell
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA
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Estevan J, Maréna A, Callot C, Lacombe S, Moretti A, Caranta C, Gallois JL. Specific requirement for translation initiation factor 4E or its isoform drives plant host susceptibility to Tobacco etch virus. BMC Plant Biol 2014; 14:67. [PMID: 24645730 PMCID: PMC3999954 DOI: 10.1186/1471-2229-14-67] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/12/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND In plants, eIF4E translation initiation factors and their eIFiso4E isoforms are essential susceptibility factors for many RNA viruses, including potyviruses. Mutations altering these factors are a major source of resistance to the viruses. The eIF4E allelic series is associated with specific resistance spectra in crops such as Capsicum annum. Genetic evidence shows that potyviruses have a specific requirement for a given 4E isoform that depends on the host plant. For example, Tobacco etch virus (TEV) uses eIF4E1 to infect Capsicum annuum but uses eIFiso4E to infect Arabidopsis thaliana. Here, we investigated how TEV exploits different translation initiation factor isoforms to infect these two plant species. RESULTS A complementation system was set up in Arabidopsis to test the restoration of systemic infection by TEV. Using this system, Arabidopsis susceptibility to TEV was complemented with a susceptible pepper eIF4E1 allele but not with a resistant allele. Therefore, in Arabidopsis, TEV can use the pepper eIF4E1 instead of the endogenous eIFiso4E isoform so is able to switch between translation initiation factor 4E isoform to infect the same host. Moreover, we show that overexpressing the pepper eIF4E1 alleles is sufficient to make Arabidopsis susceptible to an otherwise incompatible TEV strain. Lastly, we show that the resistant eIF4E1 allele is similarly overcome by a resistance-breaking TEV strain as in pepper, confirming that this Arabidopsis TEV-susceptibility complementation system is allele-specific. CONCLUSION We report here a complementation system in Arabidopsis that makes it possible to assess the role of pepper pvr2-eIF4E alleles in susceptibility to TEV. Heterologous complementation experiments showed that the idiosyncratic properties of the 4E and iso4E proteins create a major checkpoint for viral infection of different hosts. This system could be used to screen natural or induced eIF4E alleles to find and study alleles of interest for plant breeding.
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Affiliation(s)
- Joan Estevan
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - Aramata Maréna
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - Caroline Callot
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - Séverine Lacombe
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - André Moretti
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - Carole Caranta
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
| | - Jean-Luc Gallois
- INRA-UR1052, Genetics and Breeding of Fruits and Vegetables, Dom. St Maurice, CS 60094, Montfavet Cedex F-84143, France
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29
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Liu LY, Wang J, Huang Y, Pan HB, Zhang X, Huang ZX, Zhao SM, Gao SZ. The effect of dietary protein levels on the expression of genes coding for four selected protein translation initiation factors in muscle tissue of Wujin pig. J Anim Physiol Anim Nutr (Berl) 2013; 98:310-7. [PMID: 23718228 DOI: 10.1111/jpn.12081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 04/11/2013] [Indexed: 01/11/2023]
Abstract
The objective of this study was to investigate the regulatory mechanism underlying the increased muscle protein accumulation in pigs while were fed a high protein diet. The eukaryotic initiation factors (eIFs) have been reported to involve in muscle protein synthesis. We investigated the mRNA and protein expression levels of eIF2B1, 4A1, 4B and 4E in Wujin pigs fed either a high protein (HP: 18%) or a low protein (LP: 14%) diet at 30, 60 or 100 kg body weight, based on real-time PCR and western blotting analyses. Our results indicated that the expression levels of eIF2B1 mRNA and protein were increased by HP diet at all body weight. The HP diet showed higher mRNA and protein levels of eIF4B gene at 60 and 100 kg. The protein expression of eIF4E phosphorylation was increased by HP diet only at 30 kg. These data suggested that the HP diet promoted porcine muscle protein accumulation mainly by up-regulating eIF2B1, 4B and 4E rather than 4A1 expression along the growth stages.
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Affiliation(s)
- L Y Liu
- College of Life Sciences, Yunnan Normal University, Kunming, Yunnan, China
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30
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Abstract
Cytoplasmic poly(A)-binding proteins (PABPs) regulate mRNA stability and translation. Although predominantly localized in the cytoplasm, PABP proteins also cycle through the nucleus. Recent work has established that their steady-state localization can be altered by cellular stresses such as ultraviolet (UV) radiation, and infection by several viruses, resulting in nuclear accumulation of PABPs. Here, we present further evidence that their interaction with and release from mRNA and translation complexes are important in determining their sub-cellular distribution and propose an integrated model for regulated nucleo-cytoplasmic transport of PABPs.
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31
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Li W, Hoffman DW. Structure and dynamics of translation initiation factor aIF-1A from the archaeon Methanococcus jannaschii determined by NMR spectroscopy. Protein Sci 2001; 10:2426-38. [PMID: 11714910 PMCID: PMC2374032 DOI: 10.1110/ps.18201] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Translation initiation factor 1A (aIF-1A) from the archaeon Methanococcus jannaschii was expressed in Escherichia coli, purified, and characterized in terms of its structure and dynamics using multidimensional NMR methods. The protein was found to be a member of the OB-fold family of RNA-associated proteins, containing a barrel of five beta-strands, a feature that is shared with the homologous eukaryotic translation initiation factor 1A (eIF-1A), as well as the prokaryotic translation initiation factor IF1. External to the beta barrel, aIF-1A contains an alpha-helix at its C-terminal and a flexible loop at its N-terminal, features that are qualitatively similar to those found in eIF-1A, but not present in prokaryotic IF1. The structural model of aIF-1A, when used in combination with primary sequence information for aIF-1A in divergent species, permitted the most-conserved residues on the protein surface to be identified, including the most likely candidates for direct interaction with the 16S ribosomal RNA and other components of the translational apparatus. Several of the conserved surface residues appear to be unique to the archaea. Nitrogen-15 relaxation and amide exchange rate data were used to characterize the internal motions within aIF-1A, providing evidence that the protein surfaces that are most likely to participate in intermolecular interactions are relatively flexible. A model is proposed, suggesting some specific interactions that may occur between aIF-1A and the small subunit of the archaeal ribosome.
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Affiliation(s)
- W Li
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, 78712, USA
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