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Al Otaibi A, Al Shaikh Mubarak S, Al Hejji F, Almasaud A, Al Jami H, Iqbal J, Al Qarni A, Harbi NKA, Bakillah A. Thapsigargin and Tunicamycin Block SARS-CoV-2 Entry into Host Cells via Differential Modulation of Unfolded Protein Response (UPR), AKT Signaling, and Apoptosis. Cells 2024; 13:769. [PMID: 38727305 PMCID: PMC11083125 DOI: 10.3390/cells13090769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/05/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND SARS-Co-V2 infection can induce ER stress-associated activation of unfolded protein response (UPR) in host cells, which may contribute to the pathogenesis of COVID-19. To understand the complex interplay between SARS-Co-V2 infection and UPR signaling, we examined the effects of acute pre-existing ER stress on SARS-Co-V2 infectivity. METHODS Huh-7 cells were treated with Tunicamycin (TUN) and Thapsigargin (THA) prior to SARS-CoV-2pp transduction (48 h p.i.) to induce ER stress. Pseudo-typed particles (SARS-CoV-2pp) entry into host cells was measured by Bright GloTM luciferase assay. Cell viability was assessed by cell titer Glo® luminescent assay. The mRNA and protein expression was evaluated by RT-qPCR and Western Blot. RESULTS TUN (5 µg/mL) and THA (1 µM) efficiently inhibited the entry of SARS-CoV-2pp into host cells without any cytotoxic effect. TUN and THA's attenuation of virus entry was associated with differential modulation of ACE2 expression. Both TUN and THA significantly reduced the expression of stress-inducible ER chaperone GRP78/BiP in transduced cells. In contrast, the IRE1-XBP1s and PERK-eIF2α-ATF4-CHOP signaling pathways were downregulated with THA treatment, but not TUN in transduced cells. Insulin-mediated glucose uptake and phosphorylation of Ser307 IRS-1 and downstream p-AKT were enhanced with THA in transduced cells. Furthermore, TUN and THA differentially affected lipid metabolism and apoptotic signaling pathways. CONCLUSIONS These findings suggest that short-term pre-existing ER stress prior to virus infection induces a specific UPR response in host cells capable of counteracting stress-inducible elements signaling, thereby depriving SARS-Co-V2 of essential components for entry and replication. Pharmacological manipulation of ER stress in host cells might provide new therapeutic strategies to alleviate SARS-CoV-2 infection.
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Affiliation(s)
- Abeer Al Otaibi
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
- Biomedical Research Department, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Al Ahsa 36428, Saudi Arabia
- King Abdulaziz Hospital, Ministry of National Guard-Health Affairs (MNG-HA), Al Ahsa 36428, Saudi Arabia
| | - Sindiyan Al Shaikh Mubarak
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
- Biomedical Research Department, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Al Ahsa 36428, Saudi Arabia
- King Abdulaziz Hospital, Ministry of National Guard-Health Affairs (MNG-HA), Al Ahsa 36428, Saudi Arabia
| | - Fatimah Al Hejji
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
| | - Abdulrahman Almasaud
- Vaccine Development Unit, Department of Infectious Disease Research, King Abdullah International Medical Research Center, Riyadh 11481, Saudi Arabia; (A.A.); (H.A.J.); (N.K.A.H.)
| | - Haya Al Jami
- Vaccine Development Unit, Department of Infectious Disease Research, King Abdullah International Medical Research Center, Riyadh 11481, Saudi Arabia; (A.A.); (H.A.J.); (N.K.A.H.)
| | - Jahangir Iqbal
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
- Biomedical Research Department, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Al Ahsa 36428, Saudi Arabia
- King Abdulaziz Hospital, Ministry of National Guard-Health Affairs (MNG-HA), Al Ahsa 36428, Saudi Arabia
| | - Ali Al Qarni
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
- Biomedical Research Department, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Al Ahsa 36428, Saudi Arabia
- King Abdulaziz Hospital, Ministry of National Guard-Health Affairs (MNG-HA), Al Ahsa 36428, Saudi Arabia
| | - Naif Khalaf Al Harbi
- Vaccine Development Unit, Department of Infectious Disease Research, King Abdullah International Medical Research Center, Riyadh 11481, Saudi Arabia; (A.A.); (H.A.J.); (N.K.A.H.)
| | - Ahmed Bakillah
- King Abdullah International Medical Research Center (KAIMRC), Eastern Region, Al Ahsa 31982, Saudi Arabia; (A.A.O.); (S.A.S.M.); (F.A.H.); (J.I.); (A.A.Q.)
- Biomedical Research Department, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Al Ahsa 36428, Saudi Arabia
- King Abdulaziz Hospital, Ministry of National Guard-Health Affairs (MNG-HA), Al Ahsa 36428, Saudi Arabia
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Loan Young T, Chang Wang K, James Varley A, Li B. Clinical Delivery of Circular RNA: Lessons Learned from RNA Drug Development. Adv Drug Deliv Rev 2023; 197:114826. [PMID: 37088404 DOI: 10.1016/j.addr.2023.114826] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/28/2023] [Accepted: 04/11/2023] [Indexed: 04/25/2023]
Abstract
Circular RNAs (circRNA) represent a distinct class of covalently closed-loop RNA molecules, which play diverse roles in regulating biological processes and disease states. The enhanced stability of synthetic circRNAs compared to their linear counterparts has recently garnered considerable research interest, paving the way for new therapeutic applications. While clinical circRNA technology is still in its early stages, significant advancements in mRNA technology offer valuable insights into its potential future applications. Two primary obstacles that must be addressed are the development of efficient production methods and the optimization of delivery systems. To expedite progress in this area, this review aims to provide an overview of the current state of knowledge on circRNA structure and function, outline recent techniques for synthesizing circRNAs, highlight key delivery strategies and applications, and discuss the current challenges and future prospects in the field of circRNA-based therapeutics.
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Affiliation(s)
- Tiana Loan Young
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Kevin Chang Wang
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Andrew James Varley
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Bowen Li
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3M2, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C1, Canada.
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3
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Bracic Tomazic S, Schatz C, Haybaeck J. Translational Regulation in Hepatocellular Carcinogenesis. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:4359-4369. [PMID: 34703211 PMCID: PMC8523516 DOI: 10.2147/dddt.s255582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/04/2021] [Indexed: 12/17/2022]
Abstract
The mortality of hepatocellular carcinoma (HCC) is distributed unevenly worldwide. One of the major causes is hepatitis B or hepatitis C virus infection and the development and progression of liver cirrhosis. The carcinogenesis of HCC is among others regulated via the mTOR (mechanistic target of rapamycin) signaling pathway and represents a possible method of targeted treatment. The aim of our article was to address the most recent clinical advances and findings of basic studies on the mTOR signaling pathway and the involved factors. Risk factors play a key role in dysregulation of the signaling pathway, where both mTORCs are upregulated and protein synthesis is altered. eIFs and, to a lesser extent, eEFs play an essential role in this process. Whether the factor will be upregulated or downregulated, among others, depends on hepatitis B/C virus infection. The amount of a particular factor in a patient sample lets us know whether HCC recurrence will occur, what is the likelihood of chemoresistance, and what outcome is predicted for patients with an increased value. Our analysis shows that in addition to mTOR, eIF3, eIF4, and eIF5 play an important role, as they can serve as biomarkers for non- and virus-related HCC.
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Affiliation(s)
- Suzana Bracic Tomazic
- Department of Pathology, Hospital Graz II, Graz, 8020, Austria.,Faculty of Medicine, University of Maribor, Maribor, 2000, Slovenia
| | - Christoph Schatz
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Johannes Haybaeck
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, 6020, Austria.,Diagnostic & Research Center for Molecular BioMedicine, Institute of Pathology, Medical University Graz, Graz, 8010, Austria
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4
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Lee HC, Fu CY, Lin CY, Hu JR, Huang TY, Lo KY, Tsai HY, Sheu JC, Tsai HJ. Poly(U)-specific endoribonuclease ENDOU promotes translation of human CHOP mRNA by releasing uORF element-mediated inhibition. EMBO J 2021; 40:e104123. [PMID: 33511665 PMCID: PMC8167367 DOI: 10.15252/embj.2019104123] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 11/18/2020] [Accepted: 11/30/2020] [Indexed: 12/24/2022] Open
Abstract
Upstream open reading frames (uORFs) are known to negatively affect translation of the downstream ORF. The regulatory proteins involved in relieving this inhibition are however poorly characterized. In response to cellular stress, eIF2α phosphorylation leads to an inhibition of global protein synthesis, while translation of specific factors such as CHOP is induced. We analyzed a 105‐nt inhibitory uORF in the transcript of human CHOP (huORFchop) and found that overexpression of the zebrafish or human ENDOU poly(U)‐endoribonuclease (Endouc or ENDOU‐1, respectively) increases CHOP mRNA translation also in the absence of stress. We also found that Endouc/ENDOU‐1 binds and cleaves the huORFchop transcript at position 80G‐81U, which induces CHOP translation independently of phosphorylated eIF2α. However, both ENDOU and phospho‐eIF2α are nonetheless required for maximal translation of CHOP mRNA. Increased levels of ENDOU shift a huORFchop reporter as well as endogenous CHOP transcripts from the monosome to polysome fraction, indicating an increase in translation. Furthermore, we found that the uncapped truncated huORFchop‐69‐105‐nt transcript contains an internal ribosome entry site (IRES), facilitating translation of the cleaved transcript. Therefore, we propose a model where ENDOU‐mediated transcript cleavage positively regulates CHOP translation resulting in increased CHOP protein levels upon stress. Specifically, CHOP transcript cleavage changes the configuration of huORFchop thereby releasing its inhibition and allowing the stalled ribosomes to resume translation of the downstream ORF.
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Affiliation(s)
- Hung-Chieh Lee
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Chuan-Yang Fu
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Cheng-Yung Lin
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan
| | - Jia-Rung Hu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
| | - Ting-Ying Huang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
| | - Kai-Yin Lo
- Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan
| | - Hsin-Yue Tsai
- Institute of Molecular Medicine, School of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jin-Chuan Sheu
- Liver Disease Prevention and Treatment Research Foundation, Taipei, Taiwan
| | - Huai-Jen Tsai
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan.,Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan.,Department of Life Science, Fu Jen Catholic University, New Taipei, Taiwan
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5
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de Breyne S, Vindry C, Guillin O, Condé L, Mure F, Gruffat H, Chavatte L, Ohlmann T. Translational control of coronaviruses. Nucleic Acids Res 2020; 48:12502-12522. [PMID: 33264393 PMCID: PMC7736815 DOI: 10.1093/nar/gkaa1116] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 12/14/2022] Open
Abstract
Coronaviruses represent a large family of enveloped RNA viruses that infect a large spectrum of animals. In humans, the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is responsible for the current COVID-19 pandemic and is genetically related to SARS-CoV and Middle East respiratory syndrome-related coronavirus (MERS-CoV), which caused outbreaks in 2002 and 2012, respectively. All viruses described to date entirely rely on the protein synthesis machinery of the host cells to produce proteins required for their replication and spread. As such, virus often need to control the cellular translational apparatus to avoid the first line of the cellular defense intended to limit the viral propagation. Thus, coronaviruses have developed remarkable strategies to hijack the host translational machinery in order to favor viral protein production. In this review, we will describe some of these strategies and will highlight the role of viral proteins and RNAs in this process.
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Affiliation(s)
- Sylvain de Breyne
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Caroline Vindry
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Olivia Guillin
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Lionel Condé
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Fabrice Mure
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Henri Gruffat
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Laurent Chavatte
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
| | - Théophile Ohlmann
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007, Lyon, France
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6
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Bartas M, Brázda V, Bohálová N, Cantara A, Volná A, Stachurová T, Malachová K, Jagelská EB, Porubiaková O, Červeň J, Pečinka P. In-Depth Bioinformatic Analyses of Nidovirales Including Human SARS-CoV-2, SARS-CoV, MERS-CoV Viruses Suggest Important Roles of Non-canonical Nucleic Acid Structures in Their Lifecycles. Front Microbiol 2020; 11:1583. [PMID: 32719673 PMCID: PMC7347907 DOI: 10.3389/fmicb.2020.01583] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/17/2020] [Indexed: 12/15/2022] Open
Abstract
Non-canonical nucleic acid structures play important roles in the regulation of molecular processes. Considering the importance of the ongoing coronavirus crisis, we decided to evaluate genomes of all coronaviruses sequenced to date (stated more broadly, the order Nidovirales) to determine if they contain non-canonical nucleic acid structures. We discovered much evidence of putative G-quadruplex sites and even much more of inverted repeats (IRs) loci, which in fact are ubiquitous along the whole genomic sequence and indicate a possible mechanism for genomic RNA packaging. The most notable enrichment of IRs was found inside 5'UTR for IRs of size 12+ nucleotides, and the most notable enrichment of putative quadruplex sites (PQSs) was located before 3'UTR, inside 5'UTR, and before mRNA. This indicates crucial regulatory roles for both IRs and PQSs. Moreover, we found multiple G-quadruplex binding motifs in human proteins having potential for binding of SARS-CoV-2 RNA. Non-canonical nucleic acids structures in Nidovirales and in novel SARS-CoV-2 are therefore promising druggable structures that can be targeted and utilized in the future.
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Affiliation(s)
- Martin Bartas
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Václav Brázda
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
- Faculty of Chemistry, Brno University of Technology, Brno, Czechia
| | - Natália Bohálová
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
| | - Alessio Cantara
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
| | - Adriana Volná
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Tereza Stachurová
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Kateřina Malachová
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Eva B. Jagelská
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
| | - Otília Porubiaková
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
- Faculty of Chemistry, Brno University of Technology, Brno, Czechia
| | - Jiří Červeň
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Petr Pečinka
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czechia
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7
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HCV-2a NS5A downregulates viral translation predominantly through domain I. Biochem Biophys Res Commun 2020; 529:77-84. [PMID: 32560823 DOI: 10.1016/j.bbrc.2020.05.177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/25/2020] [Indexed: 11/21/2022]
Abstract
Hepatitis C virus (HCV) non-structural protein NS5A is a multifunctional protein with critical roles in viral replication and assembly. We previously showed that HCV-1b NS5A downregulates viral translation only in the presence of the poly(U/UC) tract in 3'UTR. As NS5A of different HCV genotypes may have different functions or carry out the same functions through genotype-specific mechanisms, we investigated the effect of HCV-2a NS5A on viral translation. We found that HCV-2a NS5A downregulates RNA translation of both HCV-2a and -1b, whereas the effect of HCV-1b NS5A is limited to HCV-1b only. In addition, individual regions of 3'UTR are not required for HCV-2a NS5A to downregulate viral RNA translation. We also found that HCV-2a NS5A inhibits capped mRNA translation. Mapping experiments showed that the translation downregulation by HCV-2a NS5A is predominantly mediated by domain I. Furthermore, we found that the integrity of serine-146 residue plays an important role in translation downregulation by NS5A. Our results increased our understanding on genotype-specific functions of HCV NS5A.
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8
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Dzananovic E, McKenna SA, Patel TR. Viral proteins targeting host protein kinase R to evade an innate immune response: a mini review. Biotechnol Genet Eng Rev 2018; 34:33-59. [PMID: 29716441 DOI: 10.1080/02648725.2018.1467151] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The innate immune system offers a first line of defense by neutralizing foreign pathogens such as bacteria, fungi, and viruses. These pathogens express molecules (RNA and proteins) that have discrete structures, known as the pathogen-associated molecular patterns that are recognized by a highly specialized class of host proteins called pattern recognition receptors to facilitate the host's immune response against infection. The RNA-dependent Protein Kinase R (PKR) is one of the host's pattern recognition receptors that is a key component of an innate immune system. PKR recognizes imperfectly double-stranded non-coding viral RNA molecules via its N-terminal double-stranded RNA binding motifs, undergoes phosphorylation of the C-terminal kinase domain, ultimately resulting in inhibition of viral protein translation by inhibiting the guanine nucleotide exchange activity of eukaryotic initiation factor 2α. Not surprisingly, viruses have evolved mechanisms by which viral non-coding RNA or protein molecules inhibit PKR's activation and/or its downstream activity to allow viral replication. In this review, we will highlight the role of viral proteins in inhibiting PKR's activity and summarize currently known mechanisms by which viral proteins execute such inhibitory activity.
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Affiliation(s)
- Edis Dzananovic
- a Plant Pathology, Plant Protection and Molecular Biology , Agriculture and Agri-Food Canada , Saskatoon , Canada
| | - Sean A McKenna
- b Department of Chemistry, Manitoba Institute for Materials, Department of Biochemistry and Medical Genetics , University of Manitoba , Winnipeg , Canada
| | - Trushar R Patel
- c Department of Chemistry and Biochemistry , Alberta RNA Research and Training Institute, University of Lethbridge , Lethbridge , Canada.,d DiscoveryLab, Faculty of Medicine & Dentistry , University of Alberta , Edmonton , Canada.,e Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine , University of Calgary , Calgary , Canada
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9
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Golob-Schwarzl N, Krassnig S, Toeglhofer AM, Park YN, Gogg-Kamerer M, Vierlinger K, Schröder F, Rhee H, Schicho R, Fickert P, Haybaeck J. New liver cancer biomarkers: PI3K/AKT/mTOR pathway members and eukaryotic translation initiation factors. Eur J Cancer 2017; 83:56-70. [PMID: 28715695 DOI: 10.1016/j.ejca.2017.06.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 06/01/2017] [Indexed: 12/14/2022]
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. The initiation of protein translation is an important rate-limiting step in eukaryotes and is crucial in many viral infections. Eukaryotic translation initiation factors (eIFs) are involved in the initiation step of protein translation and are linked to the phosphatidylinositol-3-kinases PI3K/AKT/mTOR pathway. Therefore we aimed to investigate a potential role of eIFs in HCC. We herein report on the immunohistochemical expression of the various eIF subunits in 235 cases of virus-related human HCC. Additionally, we used immunoblot analysis to investigate the expression of virus-related HCC and non-virus-related HCC in comparison to controls. Mammalian target of rapamycin (or mechanistic target of rapamycin as it is known now (mTOR) and activated mTOR were significantly increased in chronic hepatitis C (HCV)-associated HCC, in HCC without a viral background, in alcoholic liver disease and Wilson disease. pPTEN, phosphatase and tensin homologue (PTEN) and pAKT showed a significant increase in HBV- and HCV-associated HCC, chronic hepatitis B, HCC without a viral background, alcoholic steatohepatitis (ASH) and Wilson disease. Phosphorylated (p)-eIF2α, eIF2α, eiF3B, eIF3D, eIF3J, p-eIF4B, eIF4G and eIF6 were upregulated in HCV-associated HCC. eIF2α, p-eIF4B, eIF5 and various eIF3 subunits were significantly increased in chronic hepatitis B (HBV)-associated HCC. HCC without viral background displayed a significant increase for the eIF subunits p-2α, 3C, 3I, 4E and 4G. We noticed engraved differences in the expression pattern between chronic hepatitis B and C, HBV- and HCV-associated HCC and non-virus-related HCC.
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Affiliation(s)
- Nicole Golob-Schwarzl
- Department of Pathology, Medical University of Graz, Austria; Center for Biomarker Research in Medicine, Graz, Austria
| | | | | | - Young Nyun Park
- Department of Pathology, Yonsei University, College of Medicine, Seoul, South Korea
| | | | | | | | - Hyungjn Rhee
- Department of Pathology, Yonsei University, University College of Medicine, Seoul, South Korea
| | - Rudolf Schicho
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Austria
| | - Peter Fickert
- Division of Gastroenterology and Hepatology, Medical University of Graz, Austria
| | - Johannes Haybaeck
- Department of Pathology, Medical University of Graz, Austria; Center for Biomarker Research in Medicine, Graz, Austria; Department of Pathology, Otto-von-Guericke-University Magdeburg, Germany.
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10
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Calderon BM, Conn GL. Human noncoding RNA 886 (nc886) adopts two structurally distinct conformers that are functionally opposing regulators of PKR. RNA (NEW YORK, N.Y.) 2017; 23:557-566. [PMID: 28069888 PMCID: PMC5340918 DOI: 10.1261/rna.060269.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/03/2017] [Indexed: 05/22/2023]
Abstract
The double-stranded RNA (dsRNA)-activated protein kinase (PKR) senses dsRNA produced during viral infection and halts cellular protein synthesis to block viral replication. How basal PKR activity is controlled in the absence of infection was unclear until the recent identification of a potential endogenous regulator, the cellular noncoding RNA 886 (nc886). However, nc886 adopts two distinct conformations for which the structural details and potential functional differences remain unclear. Here, we isolated and separately dissected the function of each form of nc886 to more clearly define the molecular mechanism of nc886-mediated PKR inhibition. We show that nc886 adopts two stable, noninterconverting RNA conformers that are functionally nonequivalent using complementary RNA structure probing and mutational analyses combined with PKR binding and activity assays. One conformer acts as a potent inhibitor, while the other is a pseudoinhibitor capable of weakly activating the kinase. We mapped the nc886 region necessary for high affinity binding and potent inhibition of PKR to an apical stem-loop structure present in only one conformer of the RNA. This structural feature is not only critical for inhibiting PKR autophosphorylation, but also the phosphorylation of its cellular substrate, the eukaryotic translation initiation factor 2α subunit. The identification of different activities of the nc886 conformers suggests a potential mechanism for producing a gradient of PKR regulation within the cell and reveals a way by which a cellular noncoding RNA can mask or present a structural feature to PKR for inhibition.
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Affiliation(s)
- Brenda M Calderon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
- Graduate Program in Biochemistry, Cell and Developmental Biology (BCDB), Emory University, Atlanta, Georgia 30322 USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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11
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Sanz MA, González Almela E, Carrasco L. Translation of Sindbis Subgenomic mRNA is Independent of eIF2, eIF2A and eIF2D. Sci Rep 2017; 7:43876. [PMID: 28240315 PMCID: PMC5327398 DOI: 10.1038/srep43876] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/01/2017] [Indexed: 12/31/2022] Open
Abstract
Translation of Sindbis virus subgenomic mRNA (sgmRNA) can occur after inactivation of eIF2 by phosphorylation in mammalian cells. Several studies have suggested that eIF2 can be replaced by eIF2A or eIF2D. HAP1 human cell lines knocked-out for eIF2A, eIF2D or both by CRISPR/Cas9 genome engineering were compared with wild-type (WT) cells to test the potential role of eIF2A and eIF2D in translation. Sindbis virus infection was comparable between the four cell lines. Moreover, synthesis of viral proteins during late stage infection was similar in all four cell lines despite the fact that eIF2α became phosphorylated. These findings demonstrate that eIF2A and eIF2D are not required for the translation of sgmRNA when eIF2α is phosphorylated. Moreover, silencing of eIF2A or eIF2D by transfection of the corresponding siRNAs in HAP1 WT, HAP1-eIF2A− and HAP1-eIF2D− cells had little effect on the synthesis of viral proteins late in infection. Modification of AUGi to other codons in sgmRNA failed to abrogate translation. Sindbis virus replicons containing these sgmRNA variants could still direct the synthesis of viral proteins. No significant differences were found between the cell lines assayed, suggesting that neither eIF2A nor eIF2D are involved in the translation of this sgmRNA bearing non-AUG codons.
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Affiliation(s)
- Miguel Angel Sanz
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM) Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Esther González Almela
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM) Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Luis Carrasco
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM) Universidad Autónoma de Madrid, 28049, Madrid, Spain
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12
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Blin J, Ricci EP. [An intimate look at the viral replication cycle through ribosome profiling]. Med Sci (Paris) 2016; 32:849-860. [PMID: 27758749 DOI: 10.1051/medsci/20163210018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Next Generation Sequencing (NGS) techniques have revolutionized most biomedical research fields over the past decade by allowing a broader vision on biological processes that occur at the molecular level. Among these, ribosome profiling or footprinting is a powerful tool to study mRNA translation in a transcriptome-wide manner. Ribosome profiling has been used to study the impact of translational control of gene expression under many different cellular conditions including viral infections. Indeed, translation is a critical step during the viral replication cycle in which the infected cell is embezzled to produce viral proteins. Ribosome profiling tools can provide new insights on viral translation by monitoring ribosome binding to viral and cellular RNAs with a high definition during the time course of an infection. Here, we describe the potential uses of ribosome profiling for the understanding of viral translational control and the impact of viral infection on host gene expression. We also discuss the main limitations and biases related to the technique that need to be taken into account for its use.
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Affiliation(s)
- Juliana Blin
- CIRI, international center for infectiology research, université de Lyon, 46, allée d'Italie, Lyon, France
| | - Emiliano P Ricci
- CIRI, international center for infectiology research, université de Lyon, 46, allée d'Italie, Lyon, France - Inserm, U1111, Lyon, France - École normale supérieure de Lyon, 46, allée d'Italie, 69007 Lyon, France - Université Claude Bernard Lyon 1, centre international de recherche en infectiologie, Lyon, France - CNRS, UMR5308, Lyon, France
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13
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Liu S, Wu N, Liu J, Liu H, Su X, Liu Z, Zuo Y, Chen W, Liu G, Chen Y, Ming Y, Yuan T, Li X, Chen J, Xia Z, Wang S, Chen J, Liu T, Yang X, Ma Y, Zhang J, Shen J, Li S, Wang Y, Zhao H, Yu K, Zhao Y, Huang S, Weng X, Qiu G, Wan C, Zhou G, Wu Z. Association between ADAMTS-4 gene polymorphism and lumbar disc degeneration in Chinese Han population. J Orthop Res 2016; 34:860-4. [PMID: 26495885 DOI: 10.1002/jor.23081] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/20/2015] [Indexed: 02/05/2023]
Abstract
Low back pain (LBP) is a common health problem and many LBP are caused by lumbar disc degeneration (LDD). ADAMTS-4 (a disintegrin and metalloprotease with thrombospondin motifs-4), also known as aggrecanse-1, plays a core role in degeneration of extracellular matrix in LDD. To investigate the association between ADAMTS-4 genetic polymorphism and LDD, we genotyped SNPs in and around ADAMTS-4. We recruited 482 sporadic cases of LDD and 496 healthy controls from Chinese Han population. Five SNPs were selected and phenotyped by the Sequenom MassARRAY system. Allelic, genotypic, and haplotypic association was performed. Rs4233367 (c.1877 C>T), which located in exon of ADAMTS-4 showed significant association with LDD. The T allele conferred a lower risk of LDD with an OR of 0.69 and TT genotype is at nearly one-fifth of the risk compared to CC genotype. Other tested SNPs didn't show significant difference between the case and control groups. The SNP rs4233367 in the exon of ADAMTS-4 gene may be associated with lumbar disc degeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:860-864, 2016.
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Affiliation(s)
- Sen Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China.,Beijing Key Laboratory for Genetic Research of Bone and Joint Disease, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Nan Wu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China.,Beijing Key Laboratory for Genetic Research of Bone and Joint Disease, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Jiaqi Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Hao Liu
- Biology and Biomedical Sciences, Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts
| | - Xinlin Su
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Zhenlei Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yuzhi Zuo
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Weisheng Chen
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Gang Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yixin Chen
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yue Ming
- PET-CT Center, Cancer Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No. 17, Pan Jia Yuan Nan-li, Beijing 100021, P.R. China
| | - Tangmi Yuan
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Xiao Li
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Jun Chen
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Zenan Xia
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Shengru Wang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Jia Chen
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Tao Liu
- Shenzhen Key Laboratory of Anti-Ageing and Regenerative Medicine, Center for Anti-Ageing and Regenerative Medicine, Shenzhen University Medical School, Shenzhen, Guangdong Province 506080, P.R. China
| | - Xu Yang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yufen Ma
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Jianguo Zhang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Jianxiong Shen
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Shugang Li
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yipeng Wang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Hong Zhao
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Keyi Yu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Yu Zhao
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Shishu Huang
- Department of Orthopaedic Surgery, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Xisheng Weng
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Guixing Qiu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China.,Beijing Key Laboratory for Genetic Research of Bone and Joint Disease, No.1 Shuaifuyuan, Beijing 100730, P.R. China
| | - Chao Wan
- School of Biomedical Sciences Core Laboratory, Institute of Stem Cell, Genomics and Translational Research, Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen 518057, China.,Ministry of Education Key Laboratory for Regenerative Medicine, School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong SAR 999077, China
| | - Guangqian Zhou
- Shenzhen Key Laboratory of Anti-Ageing and Regenerative Medicine, Center for Anti-Ageing and Regenerative Medicine, Shenzhen University Medical School, Shenzhen, Guangdong Province 506080, P.R. China
| | - Zhihong Wu
- Beijing Key Laboratory for Genetic Research of Bone and Joint Disease, No.1 Shuaifuyuan, Beijing 100730, P.R. China.,Central laboratory, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Beijing 100730, P.R. China
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14
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Tsukumo Y, Tsukahara S, Furuno A, Iemura SI, Natsume T, Tomida A. TBL2 is a novel PERK-binding protein that modulates stress-signaling and cell survival during endoplasmic reticulum stress. PLoS One 2014; 9:e112761. [PMID: 25393282 PMCID: PMC4231078 DOI: 10.1371/journal.pone.0112761] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/14/2014] [Indexed: 12/11/2022] Open
Abstract
Under ER stress, PKR-like ER-resident kinase (PERK) phosphorylates translation initiation factor eIF2α, resulting in repression of global protein synthesis and concomitant upregulation of the translation of specific mRNAs such as activating transcription factor 4 (ATF4). This PERK function is important for cell survival under ER stress and poor nutrient conditions. However, mechanisms of the PERK signaling pathway are not thoroughly understood. Here we identify transducin (beta)-like 2 (TBL2) as a novel PERK-binding protein. We found that TBL2 is an ER-localized type-I transmembrane protein and preferentially binds to the phosphorylated form of PERK, but not another eIF2α kinase GCN2 or ER-resident kinase IRE1, under ER stress. Immunoprecipitation analysis using various deletion mutants revealed that TBL2 interacts with PERK via the N-terminus proximal region and also associates with eIF2α via the WD40 domain. In addition, TBL2 knockdown can lead to impaired ATF4 induction under ER stress or poor nutrient conditions such as glucose and oxygen deprivation. Consistently, TBL2 knockdown rendered cells vulnerable to stresses similarly to PERK knockdown. Thus, TBL2 serves as a potential regulator of the PERK pathway.
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Affiliation(s)
- Yoshinori Tsukumo
- Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Satomi Tsukahara
- Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Aki Furuno
- Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Shun-ichiro Iemura
- Biomedicinal Information Research Center, National Institute of Advanced Industrial Science and Technology, Koto-ku, Tokyo, Japan
| | - Toru Natsume
- Biomedicinal Information Research Center, National Institute of Advanced Industrial Science and Technology, Koto-ku, Tokyo, Japan
| | - Akihiro Tomida
- Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
- * E-mail:
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15
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A unique phosphorylation-dependent eIF4E assembly on 40S ribosomes co-ordinated by hepatitis C virus protein NS5A that activates internal ribosome entry site translation. Biochem J 2014; 462:291-302. [PMID: 24894874 DOI: 10.1042/bj20131530] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We previously reported that the HCV (hepatitis C virus) protein NS5A up-regulated mRNA cap binding eIF4F (eukaryotic initiation factor 4F) complex assembly through mTOR (mechanistic target of rapamycin)-4EBP1 (eIF4E-binding protein 1) pathway and that NS5A (non-structural protein 5A) physically interacted with translation apparatus. In the present study, we demonstrate that NS5A co-ordinates a unique assembly of the cap binding protein eIF4E and 40S ribosome to form a complex that we call ENR (eIF4E-NS5A-ribosome). Recruitment of NS5A and eIF4E to 40S ribosome was confirmed by polysome fractionation, subcellular fractionation and high-salt-wash immunoprecipitation. These observations were also confirmed in HCV-infected cells, validating its biological significance. eIF4E phosphorylation was critical for ENR assembly. 80S ribosome dissociation and RNase integrity assays revealed that, once associated, the ENR complex is stable and RNA interaction is dispensable. Both the N- and C-terminal regions of NS5A domain 1 were indispensable for this assembly and for the NS5A-induced HCV IRES (internal ribosome entry site) activation. The present study demonstrates that NS5A initially associates with phosphorylated eIF4E of eIF4F complex and subsequently recruits it to 40S ribosomes. This is the first time the interaction of viral protein with both eIF4E and ribosomes has been reported. We propose that this assembly would determine the outcome of HCV infection and pathogenesis through regulation of viral and host translation.
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16
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Burugu S, Daher A, Meurs EF, Gatignol A. HIV-1 translation and its regulation by cellular factors PKR and PACT. Virus Res 2014; 193:65-77. [PMID: 25064266 DOI: 10.1016/j.virusres.2014.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/13/2014] [Accepted: 07/14/2014] [Indexed: 12/24/2022]
Abstract
The synthesis of proteins from viral mRNA is the first step towards viral assembly. Viruses are dependent upon the cellular translation machinery to synthesize their own proteins. The synthesis of proteins from the human immunodeficiency virus (HIV) type 1 and 2 RNAs utilize several alternative mechanisms. The regulation of viral protein production requires a constant interplay between viral requirements and the cell response to viral infection. Among the antiviral cell responses, the interferon-induced RNA activated protein kinase, PKR, regulates the cellular and viral translation. During HIV-1 infection, PKR activation is highly regulated by viral and cellular factors. The cellular TAR RNA Binding Protein, TRBP, the Adenosine Deaminase acting on RNA, ADAR1, and the PKR Activator, PACT, play important roles. Recent data show that PACT changes its function from activator to inhibitor in HIV-1 infected cells. Therefore, HIV-1 has evolved to replicate in cells in which TRBP, ADAR1 and PACT prevent PKR activation to allow efficient viral protein synthesis. This proper translation will initiate the assembly of viral particles.
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Affiliation(s)
- Samantha Burugu
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
| | - Aïcha Daher
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada
| | - Eliane F Meurs
- Institut Pasteur, Department of Virology, Hepacivirus and Innate Immunity Unit, Paris, France
| | - Anne Gatignol
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC, Canada.
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17
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A perspective on mammalian upstream open reading frame function. Int J Biochem Cell Biol 2013; 45:1690-700. [PMID: 23624144 PMCID: PMC7172355 DOI: 10.1016/j.biocel.2013.04.020] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 12/11/2022]
Abstract
Post-transcriptional control makes a major contribution to the overall regulation of gene expression pathway. Within the cytoplasm this is mediated by a combination of regulatory RNA motifs within the 5′ and 3′ untranslated regions of mRNAs and their interacting protein/RNA partners. One of the most common regulatory RNA elements in mammalian transcripts (present in approximately 40% of all mRNAs) are upstream open reading frames (uORFs). However, despite the prevalence of these RNA elements how they function is not well understood. In general, they act to repress translation of the physiological ORF under control conditions, and under certain pathophysiological stresses this repression can be alleviated. It is known that re-initiation following the translation of an uORF is utilised in some situations however there are numerous alternative mechanisms that control the synthesis of a protein whose mRNA contains uORFs. Moreover, the trans-acting factors that are also involved in this process are not well defined. In this review we summarise our current understanding of this area and highlight some common features of these RNA motifs that have been discovered to date.
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18
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Identification and utility of innate immune system evasion mechanisms of ASFV. Virus Res 2013; 173:87-100. [DOI: 10.1016/j.virusres.2012.10.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/09/2012] [Accepted: 10/10/2012] [Indexed: 12/24/2022]
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19
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Garcin P, Cohen S, Terpstra S, Kelly I, Foster LJ, Panté N. Proteomic analysis identifies a novel function for galectin-3 in the cell entry of parvovirus. J Proteomics 2012; 79:123-32. [PMID: 23268121 DOI: 10.1016/j.jprot.2012.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/03/2012] [Accepted: 12/15/2012] [Indexed: 12/29/2022]
Abstract
Cellular factors associated with the parvovirus minute virus of mice (MVM) during infection are thought to play important roles in the MVM life cycle but only a few of these have been identified. Here we used a proteomic-based approach in order to identify host-binding partners of MVM. Using purified MVM as bait for immunoprecipitation assays, a total of 150 proteins were identified in MVM immunoprecipitates by quantitative liquid chromatography-tandem mass spectrometry. Galectin-3 was one of six proteins showing a statistically significant enrichment across replicates. Small interfering RNA depletion studies revealed an important role for galectin-3 in MVM endocytosis and infectivity in LA9 mouse fibroblast cells. Galectin-3-depleted cells were less susceptible to MVM infection than control cells and showed a significant reduction of MVM cellular uptake, but not of MVM binding to the cell surface. Our results indicate an important role for galectin-3 in the cellular uptake of MVM. We propose that galectin-3 facilitates the access of MVM to its receptor(s) at the plasma membrane and in this way promotes MVM endocytosis.
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Affiliation(s)
- Pierre Garcin
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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20
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de Breyne S, Soto-Rifo R, López-Lastra M, Ohlmann T. Translation initiation is driven by different mechanisms on the HIV-1 and HIV-2 genomic RNAs. Virus Res 2012; 171:366-81. [PMID: 23079111 DOI: 10.1016/j.virusres.2012.10.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 02/08/2023]
Abstract
The human immunodeficiency virus (HIV) unspliced full length genomic RNA possesses features of an eukaryotic cellular mRNA as it is capped at its 5' end and polyadenylated at its 3' extremity. This genomic RNA is used both for the production of the viral structural and enzymatic proteins (Gag and Pol, respectively) and as genome for encapsidation in the newly formed viral particle. Although both of these processes are critical for viral replication, they should be controlled in a timely manner for a coherent progression into the viral cycle. Some of this regulation is exerted at the level of translational control and takes place on the viral 5' untranslated region and the beginning of the gag coding region. In this review, we have focused on the different initiation mechanisms (cap- and internal ribosome entry site (IRES)-dependent) that are used by the HIV-1 and HIV-2 genomic RNAs and the cellular and viral factors that can modulate their expression. Interestingly, although HIV-1 and HIV-2 share many similarities in the overall clinical syndrome they produce, in some aspects of their replication cycle, and in the structure of their respective genome, they exhibit some differences in the way that ribosomes are recruited on the gag mRNA to initiate translation and produce the viral proteins; this will be discussed in the light of the literature.
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21
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de Breyne S, Chamond N, Décimo D, Trabaud MA, André P, Sargueil B, Ohlmann T. In vitrostudies reveal that different modes of initiation on HIV-1 mRNA have different levels of requirement for eukaryotic initiation factor 4F. FEBS J 2012; 279:3098-111. [DOI: 10.1111/j.1742-4658.2012.08689.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Abstract
Astrovirus infections cause gastroenteritis in mammals and have been identified as causative agents of diverse pathologies in birds such as hepatitis in ducks and poult enteritis mortality syndrome (PEMS), which causes enteritis and thymic and bursal atrophy in turkeys. Human astroviruses are recognized as the second leading cause of childhood viral gastroenteritis worldwide. Eight traditional astrovirus serotypes have been identified in humans, but recently novel astrovirus strains isolated from humans have been associated with diseases other than gastroenteritis. Herein we summarize our current knowledge of the astrovirus life cycle. Though there are gaps in our understanding of astrovirus replication, similarities can be drawn from Picornaviridae and Caliciviridae virus families. There are, however, unique characteristics of the astrovirus life cycle, including intracellular proteolytic processing of viral particles by cellular caspases, which has been shown to be required for the maturation and exit of viral progeny.
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Affiliation(s)
- Stacey Schultz-Cherry
- , Infectious Diseases, St Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, 38105 Tennessee USA
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23
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George A, Panda S, Kudmulwar D, Chhatbar SP, Nayak SC, Krishnan HH. Hepatitis C virus NS5A binds to the mRNA cap-binding eukaryotic translation initiation 4F (eIF4F) complex and up-regulates host translation initiation machinery through eIF4E-binding protein 1 inactivation. J Biol Chem 2011; 287:5042-58. [PMID: 22184107 DOI: 10.1074/jbc.m111.308916] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Initiation, a major rate-limiting step of host protein translation, is a critical target in many viral infections. Chronic hepatitis C virus (HCV) infection results in hepatocellular carcinoma. Translation initiation, up-regulated in many cancers, plays a critical role in tumorigenesis. mTOR is a major regulator of host protein translation. Even though activation of PI3K-AKT-mTOR by HCV non-structural protein 5A (NS5A) is known, not much is understood about the regulation of host translation initiation by this virus. Here for the first time we show that HCV up-regulates host cap-dependent translation machinery in Huh7.5 cells through simultaneous activation of mTORC1 and eukaryotic translation initiation factor 4E (eIF4E) by NS5A. NS5A, interestingly, overexpressed and subsequently hyperphosphorylated 4EBP1. NS5A phosphorylated eIF4E through the p38 MAPK-MNK pathway. Both HCV infection and NS5A expression augmented eIF4F complex assembly, an indicator of cap-dependent translation efficiency. Global translation, however, was not altered by HCV NS5A. 4EBP1 phosphorylation, but not that of S6K1, was uniquely resistant to rapamycin in NS5A-Huh7.5 cells, indicative of an alternate phosphorylation mechanism of 4EBP1. Resistance of Ser-473, but not Thr-308, phosphorylation of AKT to PI3K inhibitors suggested an activation of mTORC2 by NS5A. NS5A associated with eIF4F complex and polysomes, suggesting its active involvement in host translation. This is the first report that implicates an HCV protein in the up-regulation of host translation initiation apparatus through concomitant regulation of multiple pathways. Because both mTORC1 activation and eIF4E phosphorylation are involved in tumorigenesis, we propose that their simultaneous activation by NS5A might contribute significantly to the development of hepatocellular carcinoma.
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Affiliation(s)
- Anju George
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad 500007, India
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24
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The mechanism of translation initiation on Aichivirus RNA mediated by a novel type of picornavirus IRES. EMBO J 2011; 30:4423-36. [PMID: 21873976 DOI: 10.1038/emboj.2011.306] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/01/2011] [Indexed: 01/17/2023] Open
Abstract
Picornavirus mRNAs contain IRESs that sustain their translation during infection, when host protein synthesis is shut off. The major classes of picornavirus IRESs (Types 1 and 2) have distinct structures and sequences, but initiation on both is determined by their specific interaction with eIF4G. We report here that Aichivirus (AV), a member of the Kobuvirus genus of Picornaviridae, contains an IRES that differs structurally from Type 1 and Type 2 IRESs. Its function similarly involves interaction with eIF4G, but its eIF4G-interacting domain is structurally distinct, although it contains an apical eIF4G-interacting motif similar to that in Type 2 IRESs. Like Type 1 and Type 2 IRESs, AV IRES function is enhanced by pyrimidine tract-binding protein (PTB), but the pattern of PTB's interaction with each of these IRESs is distinct. Unlike all known IRESs, the AV IRES is absolutely dependent on DHX29, a requirement imposed by sequestration of its initiation codon in a stable hairpin.
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Abstract
All viruses depend on the cellular protein synthesis machinery for the production of viral proteins. Thus, viruses have evolved a variety of strategies to avoid innate host responses that inhibit protein synthesis. In this issue of Genes & Development, Chuluunbaatar and colleagues (pp. 2627-2639) demonstrate that Herpes Simplex Virus-1 counteracts this response through viral kinase Us3, which mimics cellular kinase Akt to phosphorylate and repress tuberous sclerosis complex 2 (TSC2), resulting in the activation of mammalian target of rapamycin complex 1 (mTORC1) and enhancement of mRNA translation.
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Affiliation(s)
- Kara L Norman
- Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305, USA
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Wiley MR, Roberts LO, Adelman ZN, Myles KM. Double subgenomic alphaviruses expressing multiple fluorescent proteins using a Rhopalosiphum padi virus internal ribosome entry site element. PLoS One 2010; 5:e13924. [PMID: 21085714 PMCID: PMC2978087 DOI: 10.1371/journal.pone.0013924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 10/12/2010] [Indexed: 12/22/2022] Open
Abstract
Double subgenomic Sindbis virus (dsSINV) vectors are widely used for the expression of proteins, peptides, and RNA sequences. These recombinant RNA viruses permit high level expression of a heterologous sequence in a wide range of animals, tissues, and cells. However, the alphavirus genome structure and replication strategy is not readily amenable to the expression of more than one heterologous sequence. The Rhopalosiphum padi virus (RhPV) genome contains two internal ribosome entry site (IRES) elements that mediate cap-independent translation of the virus nonstructural and structural proteins. Most IRES elements that have been characterized function only in mammalian cells but previous work has shown that the IRES element present in the 5′ untranslated region (UTR) of the RhPV genome functions efficiently in mammalian, insect, and plant systems. To determine if the 5′ RhPV IRES element could be used to express more than one heterologous sequence from a dsSINV vector, RhPV 5′ IRES sequences were placed between genes for two different fluorescent marker proteins in the dsSINV, TE/3′2J/mcs. While mammalian and insect cells infected with recombinant viruses containing the RhPV sequences expressed both fluorescent marker proteins, only single marker proteins were routinely observed in cells infected with dsSINV vectors in which the RhPV IRES had been replaced by a luciferase fragment, an antisense RhPV IRES, or no intergenic sequence. Thus, we report development of a versatile tool for the expression of multiple sequences in diverse cell types.
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Affiliation(s)
- Michael R. Wiley
- Fralin Life Science Institute, Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Lisa O. Roberts
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Zach N. Adelman
- Fralin Life Science Institute, Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Kevin M. Myles
- Fralin Life Science Institute, Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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