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Sobočan M, Brunialti D, Sprung S, Schatz C, Knez J, Kavalar R, Takač I, Haybaeck J. Initiation and elongation factor co-expression correlates with recurrence and survival in epithelial ovarian cancer. J Ovarian Res 2022; 15:73. [PMID: 35718769 PMCID: PMC9208098 DOI: 10.1186/s13048-022-00998-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 05/10/2022] [Indexed: 11/25/2022] Open
Abstract
High grade epithelial ovarian cancer (EOC) represents a diagnostic and therapeutic challenge due to its aggressive features and short recurrence free survival (RFS) after primary treatment. Novel targets to inform our understanding of the EOC carcinogenesis in the translational machinery can provide us with independent prognostic markers and provide drugable targets. We have identified candidate eukaryotic initiation factors (eIF) and eukaryotic elongation factors (eEF) in the translational machinery for differential expression in EOC through in-silico analysis. We present the analysis of 150 ovarian tissue microarray (TMA) samples on the expression of the translational markers eIF2α, eIF2G, eIF5 (eIF5A and eIF5B), eIF6 and eEF1A1. All translational markers were differentially expressed among non-neoplastic ovarian samples and tumour samples (borderline tumours and EOC). In EOC, expression of eIF5A was found to be significantly correlated with recurrence free survival (RFS) and expression of eIF2G and eEF1A1 with overall survival (OS). Expression correlation among factor subunits showed that the correlation of eEF1A1, eIF2G, EIF2α and eIF5A were significantly interconnected. eIF5A was also correlated with eIF5B and eIF6. Our study demonstrates that EOCs have different translational profile compared to benign ovarian tissue and that eIF5A is a central dysregulated factor of the translation machinery.
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Affiliation(s)
- Monika Sobočan
- Department of Pharmacology, Faculty of Medicine, University of Maribor, Maribor, Slovenia. .,Department of Obstetrics and Gynecology, Faculty of Medicine, University of Maribor, Maribor, Slovenia. .,Division of Gynecology and Perinatology, University Medical Centre Maribor, Maribor, Slovenia.
| | - Daniela Brunialti
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sussanne Sprung
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christoph Schatz
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jure Knez
- Department of Pharmacology, Faculty of Medicine, University of Maribor, Maribor, Slovenia.,Department of Obstetrics and Gynecology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Rajko Kavalar
- Department of Pathology, University Medical Centre Maribor, Maribor, Slovenia
| | - Iztok Takač
- Department of Pharmacology, Faculty of Medicine, University of Maribor, Maribor, Slovenia.,Department of Obstetrics and Gynecology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Johannes Haybaeck
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria.,Diagnostic & Research Center for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Graz, Austria
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2
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Koncha RR, Ramachandran G, Sepuri NBV, Ramaiah KVA. CCCP-induced mitochondrial dysfunction - characterization and analysis of integrated stress response to cellular signaling and homeostasis. FEBS J 2021; 288:5737-5754. [PMID: 33837631 DOI: 10.1111/febs.15868] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/26/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction mediated by CCCP (carbonyl cyanide m-chlorophenyl hydrazone), an inhibitor of mitochondrial oxidative phosphorylation, evokes the integrated stress response (ISR), which is analyzed here by eIF2α phosphorylation and expression profiles of ATF4 and CHOP proteins. Our findings suggest that the CCCP-induced ISR pathway is mediated by activation of HRI kinase, but not by GCN2, PERK, or PKR. Also, CCCP activates AMPK, a cellular energy sensor, and AKT, a regulator implicated in cell survival, and suppresses phosphorylation of mTORC1 substrates eIF4E-BP1 and S6K. CCCP also downregulates translation and promotes autophagy, leading to noncaspase-mediated cell death in HepG2 cells. All these events are neutralized by NAC, an anti-ROS, suggesting that CCCP-induced mitochondrial dysfunction promotes oxidative stress. ISRIB, an inhibitor of the ISR pathway, mitigates CCCP-induced expression of ATF4 and CHOP, activation of AKT, and autophagy, similar to NAC. However, it fails to reverse CCCP-induced AMPK activation, suggesting that CCCP-induced autophagy is dependent on ISR and independent of AMPK activation. ISRIB restores partly, inhibition in eIF4E-BP1 phosphorylation, promotes eIF2α phosphorylation, albeit slowly, and mitigates suppression of translation accordingly, in CCCP-treated cells. These findings are consistent with the idea that CCCP-induced oxidative stress leading to eIF2α phosphorylation and ATF4 expression, which is known to stimulate genes involved in autophagy, play a pro-survival role together with AKT activation and regulate mTOR-mediated eIF4E-BP1 phosphorylation.
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Affiliation(s)
| | - Gayatri Ramachandran
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
| | - Naresh Babu V Sepuri
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
| | - Kolluru V A Ramaiah
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
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Moradi Majd R, Mayeli M, Rahmani F. Pathogenesis and promising therapeutics of Alzheimer disease through eIF2α pathway and correspondent kinases. Metab Brain Dis 2020; 35:1241-1250. [PMID: 32681467 DOI: 10.1007/s11011-020-00600-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 07/05/2020] [Indexed: 01/10/2023]
Abstract
Eukaryotic initiation factor 2 (eIF2α) pathway is overactivated in Alzheimer disease and is probably associated with synaptic and memory deficiencies. EIF2α protein is principally in charge of the regulation of protein synthesis in eukaryotic cells. Four kinases responsible for eIF2α phosphorylation at ser-51 are: General control non-derepressible-2 kinase (GCN2), double-stranded RNA-activated protein kinase (PKR), PKR-like endoplasmic reticulum kinase (PERK), and heme-regulated inhibitor kinase (HRI) are the four kinases. They lead to reduced levels of general translation and paradoxical increase of stress-responsive mRNAs expression including the B-secretase (BACE1) and the transcriptional modulator activating transcription factor 4 (ATF4), which in turn accelerates the beta-amyloidogenesis, tau phosphorylation, proapoptotic pathway induction and autophagy elements formation leading to the main pathological hallmarks of AD. Findings suggest that genetic or pharmacological inhibition of correspondent kinases can restore memory and prevent neurodegeneration. This implies that inhibition of eIF2α phosphorylation through respondent kinases is indeed a feasible prospect of clinical application. This review discusses recent therapeutic approaches targeting eIF2α pathway and provides an overview of the links between correspondent kinases overactivation with neurodegeneration in AD.
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Affiliation(s)
- Reza Moradi Majd
- Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Mahsa Mayeli
- Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran.
| | - Farzaneh Rahmani
- Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
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4
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Yun SJ, Kim H, Jung SH, Kim JH, Ryu JE, Singh NJ, Jeon J, Han JK, Kim CH, Kim S, Jang SK, Kim WJ. The mechanistic insight of a specific interaction between 15d-Prostaglandin-J2 and eIF4A suggests an evolutionary conserved role across species. Biol Open 2018; 7:bio035402. [PMID: 30257829 PMCID: PMC6262856 DOI: 10.1242/bio.035402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/03/2018] [Indexed: 12/24/2022] Open
Abstract
15-deoxy-delta 12,14-prostaglandin J2 (15d-PGJ2) is an anti-inflammatory/anti-neoplastic prostaglandin that functions through covalent binding to cysteine residues of various target proteins. We previously showed that 15d-PGJ2 mediated anti-inflammatory responses are dependent on the translational inhibition through its interaction with eIF4A (Kim et al., 2007). Binding of 15d-PGJ2 to eIF4A specifically blocks the interaction between eIF4G and eIF4A, which leads to the formation of stress granules (SGs), which then cluster mRNAs with inhibited translation. Here, we show that the binding between 15d-PGJ2 and eIF4A specifically blocks the interaction between the MIF4G domain of eIF4G and eIF4A. To reveal the mechanism of this interaction, we used computational simulation-based docking studies and identified that the carboxyl tail of 15d-PGJ2 could stabilize the binding of 15d-PGJ2 to eIF4A through arginine 295 of eIF4A, which is the first suggestion that the 15d-PGJ2 tail plays a physiological role. Interestingly, the putative 15d-PGJ2 binding site on eiF4A is conserved across many species, suggesting a biological role. Our data propose that studying 15d-PGJ2 and its targets may uncover new therapeutic approaches in anti-inflammatory drug discovery.
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Affiliation(s)
- So Jeong Yun
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hyunjoon Kim
- PBC, Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Seung-Hyun Jung
- Department of Biology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Joon Hyun Kim
- PBC, Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jeong Eun Ryu
- PBC, Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - N Jiten Singh
- Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jouhyun Jeon
- Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jin-Kwan Han
- PBC, Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Cheol-Hee Kim
- Department of Biology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Sanguk Kim
- Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung Key Jang
- PBC, Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Woo Jae Kim
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5, Canada
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Wei L, Liang A, Fu Y. Expression of Ac-PK2 protein from AcMNPV improved the progeny virus production via regulation of energy metabolism and protein synthesis. RSC Adv 2018; 8:31071-31080. [PMID: 35548732 PMCID: PMC9085523 DOI: 10.1039/c8ra05172k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 08/26/2018] [Indexed: 12/18/2022] Open
Abstract
Baculovirus encoded PK2 protein can increase viral fitness through inhibition of the eIF2α family kinases activity. Previous studies indicated that the virus might take over the control of cellular machinery post-infection, which would impose a high metabolic burden to infected insect cells. Here we showed that eIF2α phosphorylation decreased, with concomitant up-regulation of total and heterologous protein synthesis in AcMNPV-PK2-EGFP infected Sf9 cells and the larvae of Spodoptera exigua. Simultaneously, the lactic acid accumulation decreased and the uptake of glucose increased in AcMNPV-PK2-EGFP infected Sf9 cells. We proposed a model that Ac-PK2 protein overexpression would help protein synthesis by inhibiting eIF2α phosphorylation, which provided a more favorable scenario to support the efficient replication of the virus by re-directing the cellular metabolism toward ATP production. Finally, we confirmed that AcMNPV-PK2-EGFP could improve the production of progeny virus in infected Sf9 cells and enhance insecticidal activity against Spodoptera exigua larvae.
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Affiliation(s)
- Lili Wei
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University Taiyuan 030006 China +86 351 7011499 +86 351 7016125
| | - Aihua Liang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University Taiyuan 030006 China +86 351 7011499 +86 351 7016125
| | - Yuejun Fu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University Taiyuan 030006 China +86 351 7011499 +86 351 7016125
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6
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Zhang W, Xu J. Adaptive unfolded protein response promotes cell survival in rifampicin-treated L02 cells. Int J Mol Med 2018; 41:2233-2242. [PMID: 29393386 DOI: 10.3892/ijmm.2018.3438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/23/2018] [Indexed: 11/05/2022] Open
Abstract
An important concept in drug-induced liver injury (DILI) is adaptation, which means the injury reverses with the continuation of the drug. The mechanism of adaption of drugs remains enigmatic, adaptive unfolded protein response (UPR) is possibly involved. We once observed adaptation phenomenon of rifampicin (RFP) in animal models, in this study, we investigate the effects of RFP on adaptive UPR in L02 cells, and after inhibiting UPR by using 4-phenylbutyrate (4-PBA), the change of cell viability and cell apoptosis in RFP-treated cells. We found that with the concentration of RFP increased and the treatment time was prolonged, the glucose-regulated protein 78 (GRP78), a hallmark of the UPR, was upregulated, and was dose- and time-dependent. RFP also activates the p-eukaryotic initiation factor 2α (eIF2α) protein expression. 4-PBA decreased GRP78 and p-eIF2α protein expression levels. Moreover, FCA showed that cell apoptosis rate obviously increased, and MTT assay showed that cell survival rate obviously decreased, this indicates that after inhibiting the UPR, the cell damage increased, which shows that the UPR is an adaptation mechanism to protect cells against injury induced by RFP. This also proves that when the degree of UPR induced by RFP is relatively mild, adaptive UPR is helpful for cell survival.
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Affiliation(s)
- Weiping Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, Key Laboratory of Gastroenterology of Anhui Province, Hefei, Anhui 230022, P.R. China
| | - Jianming Xu
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, Key Laboratory of Gastroenterology of Anhui Province, Hefei, Anhui 230022, P.R. China
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7
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Leung HW, Foo G, Banumurthy G, Chai X, Ghosh S, Mitra-Ganguli T, VanDongen AMJ. The effect of Bacopa monnieri on gene expression levels in SH-SY5Y human neuroblastoma cells. PLoS One 2017; 12:e0182984. [PMID: 28832626 PMCID: PMC5568221 DOI: 10.1371/journal.pone.0182984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/27/2017] [Indexed: 12/22/2022] Open
Abstract
Bacopa monnieri is a plant used as a nootropic in Ayurveda, a 5000-year-old system of traditional Indian medicine. Although both animal and clinical studies supported its role as a memory enhancer, the molecular and cellular mechanism underlying Bacopa's nootropic action are not understood. In this study, we used deep sequencing (RNA-Seq) to identify the transcriptome changes upon Bacopa treatment on SH-SY5Y human neuroblastoma cells. We identified several genes whose expression levels were regulated by Bacopa. Biostatistical analysis of the RNA-Seq data identified biological pathways and molecular functions that were regulated by Bacopa, including regulation of mRNA translation and transmembrane transport, responses to oxidative stress and protein misfolding. Pathway analysis using the Ingenuity platform suggested that Bacopa may protect against brain damage and improve brain development. These newly identified molecular and cellular determinants may contribute to the nootropic action of Bacopa and open up a new direction of investigation into its mechanism of action.
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Affiliation(s)
- How-Wing Leung
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Gabriel Foo
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | | | - Xiaoran Chai
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sujoy Ghosh
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | | | - Antonius M J VanDongen
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
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8
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Chemical chaperone, TUDCA unlike PBA, mitigates protein aggregation efficiently and resists ER and non-ER stress induced HepG2 cell death. Sci Rep 2017. [PMID: 28630443 PMCID: PMC5476595 DOI: 10.1038/s41598-017-03940-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Stress induced BSA (bovine serum albumin) protein aggregation is effectively mitigated in vitro by TUDCA (tauroursodeoxycholic acid) than by PBA (4- phenylbutyric acid), chemical chaperones approved by FDA for the treatment of biliary cirrhosis and urea cycle disorders respectively. TUDCA, unlike PBA, enhances trypsin mediated digestion of BSA. TUDCA activates PERK, an ER-resident kinase that phosphorylates the alpha-subunit of eukaryotic initiation factor2 (eIF2α) and promotes the expression of activated transcription factor 4 (ATF4) in HepG2 cells. In contrast, PBA induced eIF2α phosphorylation is not mediated by PERK activation and results in low ATF4 expression. Neither chaperones promote expression of BiP, an ER chaperone, and CHOP (C/EBP homologous protein), downstream target of eIF2α-ATF4 pathway. Both chaperones mitigate tunicamycin induced PERK-eIF2α-ATF4-CHOP arm of UPR and expression of BiP. TUDCA, unlike PBA does not decrease cell viability and it also mitigates tunicamycin, UV-irradiation and PBA induced PARP (poly ADP-ribose polymerase) cleavage and cell death. These findings therefore suggest that TUDCA’s antiapoptotic activity to protect HepG2 cells and PBA’s activity that limits tumor cell progression may be important while considering their therapeutic potential.
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Quast RB, Ballion B, Stech M, Sonnabend A, Varga BR, Wüstenhagen DA, Kele P, Schiller SM, Kubick S. Cell-free synthesis of functional human epidermal growth factor receptor: Investigation of ligand-independent dimerization in Sf21 microsomal membranes using non-canonical amino acids. Sci Rep 2016; 6:34048. [PMID: 27670253 PMCID: PMC5037433 DOI: 10.1038/srep34048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 09/07/2016] [Indexed: 12/15/2022] Open
Abstract
Cell-free protein synthesis systems represent versatile tools for the synthesis and modification of human membrane proteins. In particular, eukaryotic cell-free systems provide a promising platform for their structural and functional characterization. Here, we present the cell-free synthesis of functional human epidermal growth factor receptor and its vIII deletion mutant in a microsome-containing system derived from cultured Sf21 cells. We provide evidence for embedment of cell-free synthesized receptors into microsomal membranes and asparagine-linked glycosylation. Using the cricket paralysis virus internal ribosome entry site and a repetitive synthesis approach enrichment of receptors inside the microsomal fractions was facilitated thereby providing analytical amounts of functional protein. Receptor tyrosine kinase activation was demonstrated by monitoring receptor phosphorylation. Furthermore, an orthogonal cell-free translation system that provides the site-directed incorporation of p-azido-L-phenylalanine is characterized and applied to investigate receptor dimerization in the absence of a ligand by photo-affinity cross-linking. Finally, incorporated azides are used to generate stable covalently linked receptor dimers by strain-promoted cycloaddition using a novel linker system.
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Affiliation(s)
- Robert B Quast
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Biljana Ballion
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), School of Soft Matter Research, University of Freiburg, Albertstr. 19, D-79104 Freiburg, Germany.,Center for Biosystems Analysis (ZBSA), University of Freiburg, Habsburger Str. 49, D-79104 Freiburg, Germany
| | - Marlitt Stech
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Andrei Sonnabend
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Balázs R Varga
- Chemical Biology Research Group, Hungarian Academy of Sciences, CNS, IOC, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Doreen A Wüstenhagen
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Péter Kele
- Chemical Biology Research Group, Hungarian Academy of Sciences, CNS, IOC, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Stefan M Schiller
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), School of Soft Matter Research, University of Freiburg, Albertstr. 19, D-79104 Freiburg, Germany.,Center for Biosystems Analysis (ZBSA), University of Freiburg, Habsburger Str. 49, D-79104 Freiburg, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
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Baculovirus protein PK2 subverts eIF2α kinase function by mimicry of its kinase domain C-lobe. Proc Natl Acad Sci U S A 2015. [PMID: 26216977 DOI: 10.1073/pnas.1505481112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) by eIF2α family kinases is a conserved mechanism to limit protein synthesis under specific stress conditions. The baculovirus-encoded protein PK2 inhibits eIF2α family kinases in vivo, thereby increasing viral fitness. However, the precise mechanism by which PK2 inhibits eIF2α kinase function remains an enigma. Here, we probed the mechanism by which PK2 inhibits the model eIF2α kinase human RNA-dependent protein kinase (PKR) as well as native insect eIF2α kinases. Although PK2 structurally mimics the C-lobe of a protein kinase domain and possesses the required docking infrastructure to bind eIF2α, we show that PK2 directly binds the kinase domain of PKR (PKR(KD)) but not eIF2α. The PKR(KD)-PK2 interaction requires a 22-residue N-terminal extension preceding the globular PK2 body that we term the "eIF2α kinase C-lobe mimic" (EKCM) domain. The functional insufficiency of the N-terminal extension of PK2 implicates a role for the adjacent EKCM domain in binding and inhibiting PKR. Using a genetic screen in yeast, we isolated PK2-activating mutations that cluster to a surface of the EKCM domain that in bona fide protein kinases forms the catalytic cleft through sandwiching interactions with a kinase N-lobe. Interaction assays revealed that PK2 associates with the N- but not the C-lobe of PKR(KD). We propose an inhibitory model whereby PK2 engages the N-lobe of an eIF2α kinase domain to create a nonfunctional pseudokinase domain complex, possibly through a lobe-swapping mechanism. Finally, we show that PK2 enhances baculovirus fitness in insect hosts by targeting the endogenous insect heme-regulated inhibitor (HRI)-like eIF2α kinase.
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Meijering RAM, Wiersma M, van Marion DMS, Zhang D, Hoogstra-Berends F, Dijkhuis AJ, Schmidt M, Wieland T, Kampinga HH, Henning RH, Brundel BJJM. RhoA Activation Sensitizes Cells to Proteotoxic Stimuli by Abrogating the HSF1-Dependent Heat Shock Response. PLoS One 2015; 10:e0133553. [PMID: 26193369 PMCID: PMC4508109 DOI: 10.1371/journal.pone.0133553] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/29/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The heat shock response (HSR) is an ancient and highly conserved program of stress-induced gene expression, aimed at reestablishing protein homeostasis to preserve cellular fitness. Cells that fail to activate or maintain this protective response are hypersensitive to proteotoxic stress. The HSR is mediated by the heat shock transcription factor 1 (HSF1), which binds to conserved heat shock elements (HSE) in the promoter region of heat shock genes, resulting in the expression of heat shock proteins (HSP). Recently, we observed that hyperactivation of RhoA conditions cardiomyocytes for the cardiac arrhythmia atrial fibrillation. Also, the HSR is annihilated in atrial fibrillation, and induction of HSR mitigates sensitization of cells to this disease. Therefore, we hypothesized active RhoA to suppress the HSR resulting in sensitization of cells for proteotoxic stimuli. METHODS AND RESULTS Stimulation of RhoA activity significantly suppressed the proteotoxic stress-induced HSR in HL-1 atrial cardiomyocytes as determined with a luciferase reporter construct driven by the HSF1 regulated human HSP70 (HSPA1A) promoter and HSP protein expression by Western Blot analysis. Inversely, RhoA inhibition boosted the proteotoxic stress-induced HSR. While active RhoA did not preclude HSF1 nuclear accumulation, phosphorylation, acetylation, or sumoylation, it did impair binding of HSF1 to the hsp genes promoter element HSE. Impaired binding results in suppression of HSP expression and sensitized cells to proteotoxic stress. CONCLUSION These results reveal that active RhoA negatively regulates the HSR via attenuation of the HSF1-HSE binding and thus may play a role in sensitizing cells to proteotoxic stimuli.
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Affiliation(s)
- Roelien A. M. Meijering
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marit Wiersma
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Denise M. S. van Marion
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Deli Zhang
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Femke Hoogstra-Berends
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Anne-Jan Dijkhuis
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Martina Schmidt
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Thomas Wieland
- Institute of Experimental and Clinical Pharmacology and Toxicology, Mannheim Medical Faculty, University of Heidelberg, Mannheim, Germany
| | - Harm H. Kampinga
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert H. Henning
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Bianca J. J. M. Brundel
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
- * E-mail:
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Gani AR, Uppala JK, Ramaiah KVA. Tauroursodeoxycholic acid prevents stress induced aggregation of proteins in vitro and promotes PERK activation in HepG2 cells. Arch Biochem Biophys 2015; 568:8-15. [PMID: 25579883 DOI: 10.1016/j.abb.2014.12.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/27/2014] [Accepted: 12/30/2014] [Indexed: 12/15/2022]
Abstract
Tauroursodeoxycholic acid (TUDCA) a bile salt and chemical chaperone reduces stress-induced aggregation of proteins; activates PERK [PKR (RNA-dependent protein kinase)-like ER (endoplasmic reticulum) kinase] or EIF2AK3, one of the hall marks of ER stress induced unfolded protein response (UPR) in human hepatoblastoma HepG2 cells; prevents heat and dithiothreitol (DTT) induced aggregation of BSA (bovine serum albumin), and reduces ANS (1-anilino-naphthalene-8-sulfonate) bound BSA fluorescence in vitro. TUDCA inactivates heat treated, but not the native EcoR1 enzyme, and reduces heat-induced aggregation and activity of COX-1 (cyclooxygenase enzyme-1) in vitro. These findings suggest that TUDCA binds to the hydrophobic regions of proteins and prevents their subsequent aggregation. This may stabilize unfolded proteins that can mount UPR or facilitate their degradation through cellular degradation pathways.
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Affiliation(s)
- Amina R Gani
- Department of Biochemistry, University of Hyderabad, Hyderabad 500046, India
| | | | - Kolluru V A Ramaiah
- Department of Biochemistry, University of Hyderabad, Hyderabad 500046, India.
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13
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Mycobacterial HBHA induces endoplasmic reticulum stress-mediated apoptosis through the generation of reactive oxygen species and cytosolic Ca2+ in murine macrophage RAW 264.7 cells. Cell Death Dis 2013; 4:e957. [PMID: 24336077 PMCID: PMC3877560 DOI: 10.1038/cddis.2013.489] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 12/31/2022]
Abstract
Mycobacterial heparin-binding haemagglutinin antigen (HBHA) is a virulence factor that induces apoptosis of macrophages. Endoplasmic reticulum (ER) stress-mediated apoptosis is an important regulatory response that can be utilised to study the pathogenesis of tuberculosis. In the present study, HBHA stimulation induced ER stress sensor molecules in a caspase-dependent manner. Pre-treatment of RAW 264.7 cells with an IκB kinase 2 inhibitor reduced not only C/EBP homology protein expression but also IL-6 and monocyte chemotactic protein-1 (MCP-1) production. BAPTA-AM reduced both ER stress responses and caspase activation and strongly suppressed HBHA-induced IL-6 and MCP-1 production in RAW 264.7 cells. Enhanced reactive oxygen species (ROS) production and elevated cytosolic [Ca(2+)]i levels were essential for HBHA-induced ER stress responses. Collectively, our data suggest that HBHA induces cytosolic [Ca(2+)]i, which influences the generation of ROS associated with the production of proinflammatory cytokines. These concerted and complex cellular responses induce ER stress-associated apoptosis during HBHA stimulation in macrophages. These results indicate that the ER stress pathway has an important role in the HBHA-induced apoptosis during mycobacterial infection.
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Nguyen Q, Nielsen LK, Reid S. Genome scale transcriptomics of baculovirus-insect interactions. Viruses 2013; 5:2721-47. [PMID: 24226166 PMCID: PMC3856412 DOI: 10.3390/v5112721] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/28/2013] [Accepted: 11/04/2013] [Indexed: 01/25/2023] Open
Abstract
Baculovirus-insect cell technologies are applied in the production of complex proteins, veterinary and human vaccines, gene delivery vectors' and biopesticides. Better understanding of how baculoviruses and insect cells interact would facilitate baculovirus-based production. While complete genomic sequences are available for over 58 baculovirus species, little insect genomic information is known. The release of the Bombyx mori and Plutella xylostella genomes, the accumulation of EST sequences for several Lepidopteran species, and especially the availability of two genome-scale analysis tools, namely oligonucleotide microarrays and next generation sequencing (NGS), have facilitated expression studies to generate a rich picture of insect gene responses to baculovirus infections. This review presents current knowledge on the interaction dynamics of the baculovirus-insect system' which is relatively well studied in relation to nucleocapsid transportation, apoptosis, and heat shock responses, but is still poorly understood regarding responses involved in pro-survival pathways, DNA damage pathways, protein degradation, translation, signaling pathways, RNAi pathways, and importantly metabolic pathways for energy, nucleotide and amino acid production. We discuss how the two genome-scale transcriptomic tools can be applied for studying such pathways and suggest that proteomics and metabolomics can produce complementary findings to transcriptomic studies.
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Affiliation(s)
- Quan Nguyen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
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15
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Adaptive changes in alphavirus mRNA translation allowed colonization of vertebrate hosts. J Virol 2012; 86:9484-94. [PMID: 22761388 DOI: 10.1128/jvi.01114-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the Alphavirus genus are arboviruses that alternate replication in mosquitoes and vertebrate hosts. In vertebrate cells, the alphavirus resists the activation of antiviral RNA-activated protein kinase (PKR) by the presence of a prominent RNA structure (downstream loop [DLP]) located in viral 26S transcripts, which allows an eIF2-independent translation initiation of these mRNAs. This article shows that DLP structure is essential for replication of Sindbis virus (SINV) in vertebrate cell lines and animals but is dispensable for replication in insect cells, where no ortholog of the vertebrate PKR gene has been found. Sequence comparisons and structural RNA analysis revealed the evolutionary conservation of DLP in SINV and predicted the existence of equivalent DLP structures in many members of the Alphavirus genus. A mutant SINV lacking the DLP structure evolved in murine cells to recover a wild-type phenotype by creating an alternative structure in the RNA that restored the translational independence for eIF2. Genetic, phylogenetic, and biochemical data presented here support an evolutionary scenario for the natural history of alphaviruses, in which the acquisition of DLP structure in their mRNAs probably allowed the colonization of vertebrate host and the consequent geographic expansion of some of these viruses worldwide.
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Stockwell SR, Platt G, Barrie SE, Zoumpoulidou G, te Poele RH, Aherne GW, Wilson SC, Sheldrake P, McDonald E, Venet M, Soudy C, Elustondo F, Rigoreau L, Blagg J, Workman P, Garrett MD, Mittnacht S. Mechanism-based screen for G1/S checkpoint activators identifies a selective activator of EIF2AK3/PERK signalling. PLoS One 2012; 7:e28568. [PMID: 22253692 PMCID: PMC3257223 DOI: 10.1371/journal.pone.0028568] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 11/10/2011] [Indexed: 01/08/2023] Open
Abstract
Human cancers often contain genetic alterations that disable G1/S checkpoint control and loss of this checkpoint is thought to critically contribute to cancer generation by permitting inappropriate proliferation and distorting fate-driven cell cycle exit. The identification of cell permeable small molecules that activate the G1/S checkpoint may therefore represent a broadly applicable and clinically effective strategy for the treatment of cancer. Here we describe the identification of several novel small molecules that trigger G1/S checkpoint activation and characterise the mechanism of action for one, CCT020312, in detail. Transcriptional profiling by cDNA microarray combined with reverse genetics revealed phosphorylation of the eukaryotic initiation factor 2-alpha (EIF2A) through the eukaryotic translation initiation factor 2-alpha kinase 3 (EIF2AK3/PERK) as the mechanism of action of this compound. While EIF2AK3/PERK activation classically follows endoplasmic reticulum (ER) stress signalling that sets off a range of different cellular responses, CCT020312 does not trigger these other cellular responses but instead selectively elicits EIF2AK3/PERK signalling. Phosphorylation of EIF2A by EIF2A kinases is a known means to block protein translation and hence restriction point transit in G1, but further supports apoptosis in specific contexts. Significantly, EIF2AK3/PERK signalling has previously been linked to the resistance of cancer cells to multiple anticancer chemotherapeutic agents, including drugs that target the ubiquitin/proteasome pathway and taxanes. Consistent with such findings CCT020312 sensitizes cancer cells with defective taxane-induced EIF2A phosphorylation to paclitaxel treatment. Our work therefore identifies CCT020312 as a novel small molecule chemical tool for the selective activation of EIF2A-mediated translation control with utility for proof-of-concept applications in EIF2A-centered therapeutic approaches, and as a chemical starting point for pathway selective agent development. We demonstrate that consistent with its mode of action CCT020312 is capable of delivering potent, and EIF2AK3 selective, proliferation control and can act as a sensitizer to chemotherapy-associated stresses as elicited by taxanes.
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Affiliation(s)
- Simon R. Stockwell
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Georgina Platt
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - S. Elaine Barrie
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Georgia Zoumpoulidou
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Robert H. te Poele
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - G. Wynne Aherne
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Stuart C. Wilson
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Peter Sheldrake
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Edward McDonald
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Mathilde Venet
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Christelle Soudy
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Frédéric Elustondo
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Laurent Rigoreau
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Julian Blagg
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Paul Workman
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Michelle D. Garrett
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Sibylle Mittnacht
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
- * E-mail:
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Lee H, Park MT, Choi BH, Oh ET, Song MJ, Lee J, Kim C, Lim BU, Park HJ. Endoplasmic reticulum stress-induced JNK activation is a critical event leading to mitochondria-mediated cell death caused by β-lapachone treatment. PLoS One 2011; 6:e21533. [PMID: 21738692 PMCID: PMC3127577 DOI: 10.1371/journal.pone.0021533] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 05/31/2011] [Indexed: 11/21/2022] Open
Abstract
Background β-lapachone (β-lap) is a bioreductive agent that is activated by the two-electron reductase NAD(P)H quinone oxidoreductase 1 (NQO1). Although β-lap has been reported to induce apoptosis in various cancer types in an NQO1-dependent manner, the signaling pathways by which β-lap causes apoptosis are poorly understood. Methodology/Principal Findings β-lap-induced apoptosis and related molecular signaling pathways in NQO1-negative and NQO1-overexpressing MDA-MB-231 cells were investigated. Pharmacological inhibitors or siRNAs against factors involved in β-lap-induced apoptosis were used to clarify the roles played by such factors in β-lap-activated apoptotic signaling pathways. β-lap leads to clonogenic cell death and apoptosis in an NQO1- dependent manner. Treatment of NQO1-overexpressing MDA-MB-231 cells with β-lap causes rapid disruption of mitochondrial membrane potential, nuclear translocation of AIF and Endo G from mitochondria, and subsequent caspase-independent apoptotic cell death. siRNAs targeting AIF and Endo G effectively attenuate β-lap-induced clonogenic and apoptotic cell death. Moreover, β-lap induces cleavage of Bax, which accumulates in mitochondria, coinciding with the observed changes in mitochondria membrane potential. Pretreatment with Salubrinal (Sal), an endoplasmic reticulum (ER) stress inhibitor, efficiently attenuates JNK activation caused by β-lap, and subsequent mitochondria-mediated cell death. In addition, β-lap-induced generation and mitochondrial translocation of cleaved Bax are efficiently blocked by JNK inhibition. Conclusions/Significance Our results indicate that β-lap triggers induction of endoplasmic reticulum (ER) stress, thereby leading to JNK activation and mitochondria-mediated apoptosis. The signaling pathways that we revealed in this study may significantly contribute to an improvement of NQO1-directed tumor therapies.
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Affiliation(s)
- Hyemi Lee
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Moon-Taek Park
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Bo-Hwa Choi
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Eun-Taex Oh
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Min-Jeong Song
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Jeonghun Lee
- Department of Polymer Science and Engineering, Inha University, Incheon, Korea
| | - Chulhee Kim
- Department of Polymer Science and Engineering, Inha University, Incheon, Korea
| | - Byung Uk Lim
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
| | - Heon Joo Park
- Department of Microbiology, College of Medicine, Center for Advanced Medical Education by BK21 Project, Inha University, Incheon, Republic of Korea
- * E-mail:
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