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Zhang J, Yang SG, Zhou FQ. Glycogen synthase kinase 3 signaling in neural regeneration in vivo. J Mol Cell Biol 2024; 15:mjad075. [PMID: 38059848 PMCID: PMC11063957 DOI: 10.1093/jmcb/mjad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/14/2023] [Accepted: 11/28/2023] [Indexed: 12/08/2023] Open
Abstract
Glycogen synthase kinase 3 (GSK3) signaling plays important and broad roles in regulating neural development in vitro and in vivo. Here, we reviewed recent findings of GSK3-regulated axon regeneration in vivo in both the peripheral and central nervous systems and discussed a few controversial findings in the field. Overall, current evidence indicates that GSK3β signaling serves as an important downstream mediator of the PI3K-AKT pathway to regulate axon regeneration in parallel with the mTORC1 pathway. Specifically, the mTORC1 pathway supports axon regeneration mainly through its role in regulating cap-dependent protein translation, whereas GSK3β signaling might be involved in regulating N6-methyladenosine mRNA methylation-mediated, cap-independent protein translation. In addition, GSK3 signaling also plays a key role in reshaping the neuronal transcriptomic landscape during neural regeneration. Finally, we proposed some research directions to further elucidate the molecular mechanisms underlying the regulatory function of GSK3 signaling and discover novel GSK3 signaling-related therapeutic targets. Together, we hope to provide an updated and insightful overview of how GSK3 signaling regulates neural regeneration in vivo.
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Affiliation(s)
- Jing Zhang
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Shu-Guang Yang
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Feng-Quan Zhou
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
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2
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Witkamp D, Oudejans E, Hoogterp L, Hu-A-Ng GV, Glaittli KA, Stevenson TJ, Huijsmans M, Abbink TEM, van der Knaap MS, Bonkowsky JL. Lithium: effects in animal models of vanishing white matter are not promising. Front Neurosci 2024; 18:1275744. [PMID: 38352041 PMCID: PMC10861708 DOI: 10.3389/fnins.2024.1275744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/04/2024] [Indexed: 02/16/2024] Open
Abstract
Vanishing white matter (VWM) is a devastating autosomal recessive leukodystrophy, resulting in neurological deterioration and premature death, and without curative treatment. Pathogenic hypomorphic variants in subunits of the eukaryotic initiation factor 2B (eIF2B) cause VWM. eIF2B is required for regulating the integrated stress response (ISR), a physiological response to cellular stress. In patients' central nervous system, reduced eIF2B activity causes deregulation of the ISR. In VWM mouse models, the extent of ISR deregulation correlates with disease severity. One approach to restoring eIF2B activity is by inhibition of GSK3β, a kinase that phosphorylates eIF2B and reduces its activity. Lithium, an inhibitor of GSK3β, is thus expected to stimulate eIF2B activity and ameliorate VWM symptoms. The effects of lithium were tested in zebrafish and mouse VWM models. Lithium improved motor behavior in homozygous eif2b5 mutant zebrafish. In lithium-treated 2b4he2b5ho mutant mice, a paradoxical increase in some ISR transcripts was found. Furthermore, at the dosage tested, lithium induced significant polydipsia in both healthy controls and 2b4he2b5ho mutant mice and did not increase the expression of other markers of lithium efficacy. In conclusion, lithium is not a drug of choice for further development in VWM based on the limited or lack of efficacy and significant side-effect profile.
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Affiliation(s)
- Diede Witkamp
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Ellen Oudejans
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Leoni Hoogterp
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Gino V. Hu-A-Ng
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Kathryn A. Glaittli
- Department of Pediatrics, University of Utah, Salt Lake City, UT, United States
| | - Tamara J. Stevenson
- Department of Pediatrics, University of Utah, Salt Lake City, UT, United States
| | - Marleen Huijsmans
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Truus E. M. Abbink
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Marjo S. van der Knaap
- Child Neurology, Emma Children’s Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Joshua L. Bonkowsky
- Department of Pediatrics, University of Utah, Salt Lake City, UT, United States
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3
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Tagliatti E, Desiato G, Mancinelli S, Bizzotto M, Gagliani MC, Faggiani E, Hernández-Soto R, Cugurra A, Poliseno P, Miotto M, Argüello RJ, Filipello F, Cortese K, Morini R, Lodato S, Matteoli M. Trem2 expression in microglia is required to maintain normal neuronal bioenergetics during development. Immunity 2024; 57:86-105.e9. [PMID: 38159572 PMCID: PMC10783804 DOI: 10.1016/j.immuni.2023.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 07/17/2023] [Accepted: 12/05/2023] [Indexed: 01/03/2024]
Abstract
Triggering receptor expressed on myeloid cells 2 (Trem2) is a myeloid cell-specific gene expressed in brain microglia, with variants that are associated with neurodegenerative diseases, including Alzheimer's disease. Trem2 is essential for microglia-mediated synaptic refinement, but whether Trem2 contributes to shaping neuronal development remains unclear. Here, we demonstrate that Trem2 plays a key role in controlling the bioenergetic profile of pyramidal neurons during development. In the absence of Trem2, developing neurons in the hippocampal cornus ammonis (CA)1 but not in CA3 subfield displayed compromised energetic metabolism, accompanied by reduced mitochondrial mass and abnormal organelle ultrastructure. This was paralleled by the transcriptional rearrangement of hippocampal pyramidal neurons at birth, with a pervasive alteration of metabolic, oxidative phosphorylation, and mitochondrial gene signatures, accompanied by a delay in the maturation of CA1 neurons. Our results unveil a role of Trem2 in controlling neuronal development by regulating the metabolic fitness of neurons in a region-specific manner.
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Affiliation(s)
- Erica Tagliatti
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Genni Desiato
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Sara Mancinelli
- Humanitas University, Department of Biomedical Sciences, Via Levi Montalicini 4, Pieve Emanuele 20072 Milan, Italy
| | - Matteo Bizzotto
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy; Humanitas University, Department of Biomedical Sciences, Via Levi Montalicini 4, Pieve Emanuele 20072 Milan, Italy
| | - Maria C Gagliani
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine (DIMES), Human Anatomy, Università di Genova, Via Antonio de Toni 14, 16132 Genova, Italy
| | - Elisa Faggiani
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | | | - Andrea Cugurra
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Paola Poliseno
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Matteo Miotto
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Rafael J Argüello
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Fabia Filipello
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Katia Cortese
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine (DIMES), Human Anatomy, Università di Genova, Via Antonio de Toni 14, 16132 Genova, Italy
| | - Raffaella Morini
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Simona Lodato
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy; Humanitas University, Department of Biomedical Sciences, Via Levi Montalicini 4, Pieve Emanuele 20072 Milan, Italy
| | - Michela Matteoli
- IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano, 20089 Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy.
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4
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So J, Wu D, Tai AK, Lichtenstein AH, Matthan NR, Lamon-Fava S. Monocyte transcriptomic profile following EPA and DHA supplementation in men and women with low-grade chronic inflammation. Atherosclerosis 2024; 388:117407. [PMID: 38091778 PMCID: PMC10872449 DOI: 10.1016/j.atherosclerosis.2023.117407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 11/16/2023] [Accepted: 11/29/2023] [Indexed: 01/15/2024]
Abstract
BACKGROUND Recent data indicate considerable variability in response to very long chain omega-3 fatty acid supplementation on cardiovascular disease risk. This inconsistency may be due to differential effects of EPA vs DHA and/or sex-specific responses. METHODS Sixteen subjects (eight men and eight women) 50-75 y and with low-grade chronic inflammation participated in a randomized controlled crossover trial comparing 3 g/d EPA, 3 g/d DHA, and placebo (3 g/d high oleic acid sunflower oil). Blood monocytes were isolated at the end of each phase for RNA-sequencing. RESULTS Sex dimorphism in monocyte gene expression was observed, therefore, data for men and women were analyzed separately. 1088 genes were differentially expressed in men and 997 in women (p < 0.05). In both men and women, EPA and DHA repressed genes involved in protein turnover and mitochondrial energy metabolism, relative to placebo. In men only, EPA and DHA upregulated genes related to wound healing and PPARα activation. In women only, EPA and DHA activated genes related to ER stress response. Relative to DHA, EPA resulted in lower expression of genes involved in inflammatory processes in men, and lower expression of genes involved in ER stress response in women. CONCLUSIONS EPA and DHA supplementation elicited both similar and differential effects on monocyte transcriptome, some of which were sex specific. The observed variability in response to EPA and DHA in men and women could in part explain the conflicting results from previous cardiovascular clinical trials using omega-3 fatty acids.
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Affiliation(s)
- Jisun So
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Alice H Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Nirupa R Matthan
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Stefania Lamon-Fava
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA.
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5
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Zhang D, Zhu L, Wang F, Li P, Wang Y, Gao Y. Molecular mechanisms of eukaryotic translation fidelity and their associations with diseases. Int J Biol Macromol 2023; 242:124680. [PMID: 37141965 DOI: 10.1016/j.ijbiomac.2023.124680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 04/27/2023] [Indexed: 05/06/2023]
Abstract
Converting genetic information into functional proteins is a complex, multi-step process, with each step being tightly regulated to ensure the accuracy of translation, which is critical to cellular health. In recent years, advances in modern biotechnology, especially the development of cryo-electron microscopy and single-molecule techniques, have enabled a clearer understanding of the mechanisms of protein translation fidelity. Although there are many studies on the regulation of protein translation in prokaryotes, and the basic elements of translation are highly conserved in prokaryotes and eukaryotes, there are still great differences in the specific regulatory mechanisms. This review describes how eukaryotic ribosomes and translation factors regulate protein translation and ensure translation accuracy. However, a certain frequency of translation errors does occur in translation, so we describe diseases that arise when the rate of translation errors reaches or exceeds a threshold of cellular tolerance.
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Affiliation(s)
- Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lei Zhu
- College of Basic Medical, Qingdao Binhai University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
| | - Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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Shao G, He T, Mu Y, Mu P, Ao J, Lin X, Ruan L, Wang Y, Gao Y, Liu D, Zhang L, Chen X. The genome of a hadal sea cucumber reveals novel adaptive strategies to deep-sea environments. iScience 2022; 25:105545. [PMID: 36444293 PMCID: PMC9700323 DOI: 10.1016/j.isci.2022.105545] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/18/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
How organisms cope with coldness and high pressure in the hadal zone remains poorly understood. Here, we sequenced and assembled the genome of hadal sea cucumber Paelopatides sp. Yap with high quality and explored its potential mechanisms for deep-sea adaptation. First, the expansion of ACOX1 for rate-limiting enzyme in the DHA synthesis pathway, increased DHA content in the phospholipid bilayer, and positive selection of EPT1 may maintain cell membrane fluidity. Second, three genes for translation initiation factors and two for ribosomal proteins underwent expansion, and three ribosomal protein genes were positively selected, which may ameliorate the protein synthesis inhibition or ribosome dissociation in the hadal zone. Third, expansion and positive selection of genes associated with stalled replication fork recovery and DNA repair suggest improvements in DNA protection. This is the first genome sequence of a hadal invertebrate. Our results provide insights into the genetic adaptations used by invertebrate in deep oceans.
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Affiliation(s)
- Guangming Shao
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Tianliang He
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yinnan Mu
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Pengfei Mu
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Jingqun Ao
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xihuang Lin
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian 361005, China
| | - Lingwei Ruan
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian 361005, China
| | - YuGuang Wang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian 361005, China
| | - Yuan Gao
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Dinggao Liu
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Liangsheng Zhang
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Xinhua Chen
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong 519000, China
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7
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Friedrich D, Marintchev A, Arthanari H. The metaphorical swiss army knife: The multitude and diverse roles of HEAT domains in eukaryotic translation initiation. Nucleic Acids Res 2022; 50:5424-5442. [PMID: 35552740 PMCID: PMC9177959 DOI: 10.1093/nar/gkac342] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Biomolecular associations forged by specific interaction among structural scaffolds are fundamental to the control and regulation of cell processes. One such structural architecture, characterized by HEAT repeats, is involved in a multitude of cellular processes, including intracellular transport, signaling, and protein synthesis. Here, we review the multitude and versatility of HEAT domains in the regulation of mRNA translation initiation. Structural and cellular biology approaches, as well as several biophysical studies, have revealed that a number of HEAT domain-mediated interactions with a host of protein factors and RNAs coordinate translation initiation. We describe the basic structural architecture of HEAT domains and briefly introduce examples of the cellular processes they dictate, including nuclear transport by importin and RNA degradation. We then focus on proteins in the translation initiation system featuring HEAT domains, specifically the HEAT domains of eIF4G, DAP5, eIF5, and eIF2Bϵ. Comparative analysis of their remarkably versatile interactions, including protein–protein and protein–RNA recognition, reveal the functional importance of flexible regions within these HEAT domains. Here we outline how HEAT domains orchestrate fundamental aspects of translation initiation and highlight open mechanistic questions in the area.
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Affiliation(s)
- Daniel Friedrich
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Assen Marintchev
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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8
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van der Knaap MS, Bonkowsky JL, Vanderver A, Schiffmann R, Krägeloh-Mann I, Bertini E, Bernard G, Fatemi SA, Wolf NI, Saunier-Vivar E, Rauner R, Dekker H, van Bokhoven P, van de Ven P, Leferink PS. Therapy Trial Design in Vanishing White Matter: An Expert Consortium Opinion. Neurol Genet 2022; 8:e657. [PMID: 35128050 PMCID: PMC8811717 DOI: 10.1212/nxg.0000000000000657] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/21/2021] [Indexed: 01/04/2023]
Abstract
Vanishing white matter (VWM) is a leukodystrophy caused by recessive variants in the genes EIF2B1-EIF2B5. It is characterized by chronic neurologic deterioration with superimposed stress-provoked episodes of rapid decline. Disease onset spans from the antenatal period through senescence. Age at onset predicts disease evolution for patients with early onset, whereas disease evolution is unpredictable for later onset; patients with infantile and early childhood onset consistently have severe disease with rapid neurologic decline and often early death, whereas patients with later onset have highly variable disease. VWM is rare, but likely underdiagnosed, particularly in adults. Apart from measures to prevent stressors that could provoke acute deteriorations, only symptomatic care is currently offered. With increased insight into VWM disease mechanisms, opportunities for treatment have emerged. EIF2B1-EIF2B5 encode the 5-subunit eukaryotic initiation factor 2B complex, which is essential for translation of mRNAs into proteins and is a principal regulator of the integrated stress response (ISR). ISR deregulation is central to VWM pathology. Targeting components of the ISR has proven beneficial in mutant VWM mouse models, and several drugs are now in clinical development. However, clinical trials in VWM pose considerable challenges: low numbers of known patients with VWM, unpredictable disease course for patients with onset after early childhood, absence of intermediate biomarkers, and novel first-in-human molecular targets. Given these challenges and considering the critical need to offer therapies, we have formulated recommendations for enhanced diagnosis, drug trial setup, and patient selection, based on our expert evaluation of molecular, laboratory, and clinical data.
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Affiliation(s)
- Marjo S. van der Knaap
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Joshua L. Bonkowsky
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Adeline Vanderver
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Raphael Schiffmann
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Ingeborg Krägeloh-Mann
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Enrico Bertini
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Genevieve Bernard
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Seyed Ali Fatemi
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Nicole I. Wolf
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Elise Saunier-Vivar
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Robert Rauner
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Hanka Dekker
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Pieter van Bokhoven
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Peter van de Ven
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Prisca S. Leferink
- From the Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
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Liu C, Miyahara H, Dai J, Cui X, Li Y, Kang X, Higuchi K, Mori M. Involvement of increased endoplasmic reticulum stress in the development of cataracts in BALB.NCT-Cpox nct mice. Exp Eye Res 2021; 215:108905. [PMID: 34968474 DOI: 10.1016/j.exer.2021.108905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/26/2021] [Accepted: 12/20/2021] [Indexed: 12/12/2022]
Abstract
The BALB.NCT-Cpoxnct is a mutant mouse model for hereditary cataracts. We previously uncovered that the primary cause of the cataracts of BALB.NCT-Cpoxnct is a mutation in the coproporphyrinogen oxidase (Cpox) gene. Because of the mutation, excessive coproporphyrin is accumulated in the BALB.NCT-Cpoxnct lens. In this study, we analyzed the changes in transcriptome and proteins in the lenses of 4- and 12-week-old BALB.NCT-Cpoxnct to further elucidate the molecular etiology of cataracts in this mouse strain. Transcriptome analysis revealed that endoplasmic reticulum (ER) stress was increased in the BALB.NCT-Cpoxnct lens that induced persistent activation of the PERK signaling pathway of the ER stress response. Also, levels of crystallin transcripts and proteins were reduced in the BALB.NCT-Cpoxnct lens. Analysis of proteins disclosed aggregation of crystallins and keratins prior to the manifestation of cataracts in 4-week-old BALB.NCT-Cpoxnct mice. At 12 weeks of age, insoluble crystallins were accumulated in the cataractous BALB.NCT-Cpoxnct lens. Overall, our data suggest the following sequence of events in the BALB.NCT-Cpoxnct lens: accumulated coproporphyrin induces the aggregation of proteins including crystallins. Aggregated proteins increase ER stress that, in turn, leads to the repression of global translation of proteins including crystallins. The decline in the molecular chaperone crystallin aggravates aggregation and insolubilization of proteins. This vicious cycle would eventually lead to cataracts in BALB.NCT-Cpoxnct.
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Affiliation(s)
- Chang Liu
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan; Department of Respiratory, The Third Hospital of Shijiazhuang, Shijiazhuang, 050011, China.
| | - Hiroki Miyahara
- Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Jian Dai
- Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Xiaoran Cui
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Ying Li
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Xiaojing Kang
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Keiichi Higuchi
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan; Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Masayuki Mori
- Department of Aging Biology, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, 390-8621, Japan; Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
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Lanciotti A, Brignone MS, Macioce P, Visentin S, Ambrosini E. Human iPSC-Derived Astrocytes: A Powerful Tool to Study Primary Astrocyte Dysfunction in the Pathogenesis of Rare Leukodystrophies. Int J Mol Sci 2021; 23:ijms23010274. [PMID: 35008700 PMCID: PMC8745131 DOI: 10.3390/ijms23010274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are very versatile cells, endowed with multitasking capacities to ensure brain homeostasis maintenance from brain development to adult life. It has become increasingly evident that astrocytes play a central role in many central nervous system pathologies, not only as regulators of defensive responses against brain insults but also as primary culprits of the disease onset and progression. This is particularly evident in some rare leukodystrophies (LDs) where white matter/myelin deterioration is due to primary astrocyte dysfunctions. Understanding the molecular defects causing these LDs may help clarify astrocyte contribution to myelin formation/maintenance and favor the identification of possible therapeutic targets for LDs and other CNS demyelinating diseases. To date, the pathogenic mechanisms of these LDs are poorly known due to the rarity of the pathological tissue and the failure of the animal models to fully recapitulate the human diseases. Thus, the development of human induced pluripotent stem cells (hiPSC) from patient fibroblasts and their differentiation into astrocytes is a promising approach to overcome these issues. In this review, we discuss the primary role of astrocytes in LD pathogenesis, the experimental models currently available and the advantages, future evolutions, perspectives, and limitations of hiPSC to study pathologies implying astrocyte dysfunctions.
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Affiliation(s)
- Angela Lanciotti
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Maria Stefania Brignone
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Pompeo Macioce
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
| | - Sergio Visentin
- National Center for Research and Preclinical and Clinical Evaluation of Drugs, Istituto Superiore di Sanità, 00169 Rome, Italy;
| | - Elena Ambrosini
- Department of Neuroscience, Istituto Superiore di Sanità, 00169 Rome, Italy; (A.L.); (M.S.B.); (P.M.)
- Correspondence: ; Tel.: +39-064-990-2037
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11
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Alberti S, Hyman AA. Biomolecular condensates at the nexus of cellular stress, protein aggregation disease and ageing. Nat Rev Mol Cell Biol 2021; 22:196-213. [PMID: 33510441 DOI: 10.1038/s41580-020-00326-6] [Citation(s) in RCA: 439] [Impact Index Per Article: 146.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 12/14/2022]
Abstract
Biomolecular condensates are membraneless intracellular assemblies that often form via liquid-liquid phase separation and have the ability to concentrate biopolymers. Research over the past 10 years has revealed that condensates play fundamental roles in cellular organization and physiology, and our understanding of the molecular principles, components and forces underlying their formation has substantially increased. Condensate assembly is tightly regulated in the intracellular environment, and failure to control condensate properties, formation and dissolution can lead to protein misfolding and aggregation, which are often the cause of ageing-associated diseases. In this Review, we describe the mechanisms and regulation of condensate assembly and dissolution, highlight recent advances in understanding the role of biomolecular condensates in ageing and disease, and discuss how cellular stress, ageing-related loss of homeostasis and a decline in protein quality control may contribute to the formation of aberrant, disease-causing condensates. Our improved understanding of condensate pathology provides a promising path for the treatment of protein aggregation diseases.
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Affiliation(s)
- Simon Alberti
- Technische Universität Dresden, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Engineering (CMCB), Dresden, Germany.
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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12
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Slynko I, Nguyen S, Hamilton EMC, Wisse LE, de Esch IJP, de Graaf C, Bruning JB, Proud CG, Abbink TEM, van der Knaap MS. Vanishing white matter: Eukaryotic initiation factor 2B model and the impact of missense mutations. Mol Genet Genomic Med 2021; 9:e1593. [PMID: 33432707 PMCID: PMC8104162 DOI: 10.1002/mgg3.1593] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 12/12/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022] Open
Abstract
Background Vanishing white matter (VWM) is a leukodystrophy, caused by recessive mutations in eukaryotic initiation factor 2B (eIF2B)‐subunit genes (EIF2B1–EIF2B5); 80% are missense mutations. Clinical severity is highly variable, with a strong, unexplained genotype–phenotype correlation. Materials and Methods With information from a recent natural history study, we severity‐graded 97 missense mutations. Using in silico modeling, we created a new human eIF2B model structure, onto which we mapped the missense mutations. Mutated residues were assessed for location in subunits, eIF2B complex, and functional domains, and for information on biochemical activity. Results Over 50% of mutations have (ultra‐)severe phenotypic effects. About 60% affect the ε‐subunit, containing the catalytic domain, mostly with (ultra‐)severe effects. About 55% affect subunit cores, with variable clinical severity. About 36% affect subunit interfaces, mostly with severe effects. Very few mutations occur on the external eIf2B surface, perhaps because they have minor functional effects and are tolerated. One external surface mutation affects eIF2B‐substrate interaction and is associated with ultra‐severe phenotype. Conclusion Mutations that lead to (ultra‐)severe disease mostly affect amino acids with pivotal roles in complex formation and function of eIF2B. Therapies for VWM are emerging and reliable mutation‐based phenotype prediction is required for propensity score matching for trials and in the future for individualized therapy decisions.
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Affiliation(s)
- Inna Slynko
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Stephanie Nguyen
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Eline M C Hamilton
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Lisanne E Wisse
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Iwan J P de Esch
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Chris de Graaf
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - John B Bruning
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Christopher G Proud
- Hopwood Centre for Neurobiology and Lifelong Health Theme, South Australian Health & Medical Research Institute, Adelaide, SA, Australia.,School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Truus E M Abbink
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, Amsterdam, the Netherlands.,Department of Functional Genomics, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
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13
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Manga P, Choudhury N. The unfolded protein and integrated stress response in melanoma and vitiligo. Pigment Cell Melanoma Res 2020; 34:204-211. [DOI: 10.1111/pcmr.12947] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/28/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Prashiela Manga
- Ronald O. Perelman Department of Dermatology New York University Grossman School of Medicine New York NY USA
| | - Noshin Choudhury
- Ronald O. Perelman Department of Dermatology New York University Grossman School of Medicine New York NY USA
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14
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Guillén-Boixet J, Kopach A, Holehouse AS, Wittmann S, Jahnel M, Schlüßler R, Kim K, Trussina IREA, Wang J, Mateju D, Poser I, Maharana S, Ruer-Gruß M, Richter D, Zhang X, Chang YT, Guck J, Honigmann A, Mahamid J, Hyman AA, Pappu RV, Alberti S, Franzmann TM. RNA-Induced Conformational Switching and Clustering of G3BP Drive Stress Granule Assembly by Condensation. Cell 2020; 181:346-361.e17. [PMID: 32302572 PMCID: PMC7181197 DOI: 10.1016/j.cell.2020.03.049] [Citation(s) in RCA: 455] [Impact Index Per Article: 113.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 10/23/2019] [Accepted: 03/20/2020] [Indexed: 12/14/2022]
Abstract
Stressed cells shut down translation, release mRNA molecules from polysomes, and form stress granules (SGs) via a network of interactions that involve G3BP. Here we focus on the mechanistic underpinnings of SG assembly. We show that, under non-stress conditions, G3BP adopts a compact auto-inhibited state stabilized by electrostatic intramolecular interactions between the intrinsically disordered acidic tracts and the positively charged arginine-rich region. Upon release from polysomes, unfolded mRNAs outcompete G3BP auto-inhibitory interactions, engendering a conformational transition that facilitates clustering of G3BP through protein-RNA interactions. Subsequent physical crosslinking of G3BP clusters drives RNA molecules into networked RNA/protein condensates. We show that G3BP condensates impede RNA entanglement and recruit additional client proteins that promote SG maturation or induce a liquid-to-solid transition that may underlie disease. We propose that condensation coupled to conformational rearrangements and heterotypic multivalent interactions may be a general principle underlying RNP granule assembly. Under non-stressed conditions, G3BP adopts a compact auto-inhibited state Conformational expansion of G3BP increases the interaction valences G3BP clusters crosslink RNA to assemble stress granules upon cellular stress G3BP condensates prevent RNA entanglement
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Affiliation(s)
- Jordina Guillén-Boixet
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Andrii Kopach
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Alex S Holehouse
- Department of Biomedical Engineering and Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA
| | - Sina Wittmann
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Marcus Jahnel
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Raimund Schlüßler
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Kyoohyun Kim
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Irmela R E A Trussina
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Jie Wang
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Daniel Mateju
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Shovamayee Maharana
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Martine Ruer-Gruß
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Doris Richter
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Xiaojie Zhang
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Young-Tae Chang
- Center for Self-Assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea; Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jochen Guck
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Simon Alberti
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
| | - Titus M Franzmann
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
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15
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Cai EY, Kufeld MN, Schuster S, Arora S, Larkin M, Germanos AA, Hsieh AC, Beronja S. Selective Translation of Cell Fate Regulators Mediates Tolerance to Broad Oncogenic Stress. Cell Stem Cell 2020; 27:270-283.e7. [PMID: 32516567 PMCID: PMC7993921 DOI: 10.1016/j.stem.2020.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 03/13/2020] [Accepted: 05/13/2020] [Indexed: 12/23/2022]
Abstract
Human skin tolerates a surprisingly high burden of oncogenic lesions. Although adult epidermis can suppress the expansion of individual mutant clones, the mechanisms behind tolerance to oncogene activation across broader regions of tissue are unclear. Here, we uncover a dynamic translational mechanism that coordinates oncogenic HRAS-induced hyperproliferation with loss of progenitor self-renewal to restrain aberrant growth and tumorigenesis. We identify translation initiator eIF2B5 as a central co-regulator of HRAS proliferation and cell fate choice. By coupling in vivo ribosome profiling with genetic screening, we provide direct evidence that oncogene-induced loss of progenitor self-renewal is driven by eIF2B5-mediated translation of ubiquitination genes. Ubiquitin ligase FBXO32 specifically inhibits epidermal renewal without affecting overall proliferation, thus restraining HRAS-driven tumorigenesis while maintaining normal tissue growth. Thus, oncogene-driven translation is not necessarily inherently tumor promoting but instead can manage widespread oncogenic stress by steering progenitor fate to prolong normal tissue growth.
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Affiliation(s)
- Elise Y Cai
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Medical Scientist Training Program, University of Washington, Seattle, WA 98195, USA; Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA
| | - Megan N Kufeld
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Samantha Schuster
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA
| | - Sonali Arora
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Madeline Larkin
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Alexandre A Germanos
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA
| | - Andrew C Hsieh
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Slobodan Beronja
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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16
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Bond S, Lopez-Lloreda C, Gannon PJ, Akay-Espinoza C, Jordan-Sciutto KL. The Integrated Stress Response and Phosphorylated Eukaryotic Initiation Factor 2α in Neurodegeneration. J Neuropathol Exp Neurol 2020; 79:123-143. [PMID: 31913484 DOI: 10.1093/jnen/nlz129] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/07/2019] [Indexed: 02/06/2023] Open
Abstract
The proposed molecular mechanisms underlying neurodegenerative pathogenesis are varied, precluding the development of effective therapies for these increasingly prevalent disorders. One of the most consistent observations across neurodegenerative diseases is the phosphorylation of eukaryotic initiation factor 2α (eIF2α). eIF2α is a translation initiation factor, involved in cap-dependent protein translation, which when phosphorylated causes global translation attenuation. eIF2α phosphorylation is mediated by 4 kinases, which, together with their downstream signaling cascades, constitute the integrated stress response (ISR). While the ISR is activated by stresses commonly observed in neurodegeneration, such as oxidative stress, endoplasmic reticulum stress, and inflammation, it is a canonically adaptive signaling cascade. However, chronic activation of the ISR can contribute to neurodegenerative phenotypes such as neuronal death, memory impairments, and protein aggregation via apoptotic induction and other maladaptive outcomes downstream of phospho-eIF2α-mediated translation inhibition, including neuroinflammation and altered amyloidogenic processing, plausibly in a feed-forward manner. This review examines evidence that dysregulated eIF2a phosphorylation acts as a driver of neurodegeneration, including a survey of observations of ISR signaling in human disease, inspection of the overlap between ISR signaling and neurodegenerative phenomenon, and assessment of recent encouraging findings ameliorating neurodegeneration using developing pharmacological agents which target the ISR. In doing so, gaps in the field, including crosstalk of the ISR kinases and consideration of ISR signaling in nonneuronal central nervous system cell types, are highlighted.
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Affiliation(s)
- Sarah Bond
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Claudia Lopez-Lloreda
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Patrick J Gannon
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cagla Akay-Espinoza
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kelly L Jordan-Sciutto
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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17
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Nüske E, Marini G, Richter D, Leng W, Bogdanova A, Franzmann TM, Pigino G, Alberti S. Filament formation by the translation factor eIF2B regulates protein synthesis in starved cells. Biol Open 2020; 9:bio046391. [PMID: 32554487 PMCID: PMC7358136 DOI: 10.1242/bio.046391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022] Open
Abstract
Cells exposed to starvation have to adjust their metabolism to conserve energy and protect themselves. Protein synthesis is one of the major energy-consuming processes and as such has to be tightly controlled. Many mechanistic details about how starved cells regulate the process of protein synthesis are still unknown. Here, we report that the essential translation initiation factor eIF2B forms filaments in starved budding yeast cells. We demonstrate that filamentation is triggered by starvation-induced acidification of the cytosol, which is caused by an influx of protons from the extracellular environment. We show that filament assembly by eIF2B is necessary for rapid and efficient downregulation of translation. Importantly, this mechanism does not require the kinase Gcn2. Furthermore, analysis of site-specific variants suggests that eIF2B assembly results in enzymatically inactive filaments that promote stress survival and fast recovery of cells from starvation. We propose that translation regulation through filament assembly is an efficient mechanism that allows yeast cells to adapt to fluctuating environments.
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Affiliation(s)
- Elisabeth Nüske
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Guendalina Marini
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Doris Richter
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Aliona Bogdanova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Titus M Franzmann
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
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18
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Schmidt S, Denk S, Wiegering A. Targeting Protein Synthesis in Colorectal Cancer. Cancers (Basel) 2020; 12:cancers12051298. [PMID: 32455578 PMCID: PMC7281195 DOI: 10.3390/cancers12051298] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 12/19/2022] Open
Abstract
Under physiological conditions, protein synthesis controls cell growth and survival and is strictly regulated. Deregulation of protein synthesis is a frequent event in cancer. The majority of mutations found in colorectal cancer (CRC), including alterations in the WNT pathway as well as activation of RAS/MAPK and PI3K/AKT and, subsequently, mTOR signaling, lead to deregulation of the translational machinery. Besides mutations in upstream signaling pathways, deregulation of global protein synthesis occurs through additional mechanisms including altered expression or activity of initiation and elongation factors (e.g., eIF4F, eIF2α/eIF2B, eEF2) as well as upregulation of components involved in ribosome biogenesis and factors that control the adaptation of translation in response to stress (e.g., GCN2). Therefore, influencing mechanisms that control mRNA translation may open a therapeutic window for CRC. Over the last decade, several potential therapeutic strategies targeting these alterations have been investigated and have shown promising results in cell lines, intestinal organoids, and mouse models. Despite these encouraging in vitro results, patients have not clinically benefited from those advances so far. In this review, we outline the mechanisms that lead to deregulated mRNA translation in CRC and highlight recent progress that has been made in developing therapeutic strategies that target these mechanisms for tumor therapy.
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Affiliation(s)
- Stefanie Schmidt
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
| | - Sarah Denk
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
| | - Armin Wiegering
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
- Department of Biochemistry and Molecular Biology, Comprehensive Cancer Center Mainfranken, University of Würzburg, 97074 Würzburg, Germany
- Correspondence: ; Tel.: +49-931-20138714
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19
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Link AJ, Niu X, Weaver CM, Jennings JL, Duncan DT, McAfee KJ, Sammons M, Gerbasi VR, Farley AR, Fleischer TC, Browne CM, Samir P, Galassie A, Boone B. Targeted Identification of Protein Interactions in Eukaryotic mRNA Translation. Proteomics 2020; 20:e1900177. [PMID: 32027465 DOI: 10.1002/pmic.201900177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/13/2019] [Indexed: 11/09/2022]
Abstract
To identify protein-protein interactions and phosphorylated amino acid sites in eukaryotic mRNA translation, replicate TAP-MudPIT and control experiments are performed targeting Saccharomyces cerevisiae genes previously implicated in eukaryotic mRNA translation by their genetic and/or functional roles in translation initiation, elongation, termination, or interactions with ribosomal complexes. Replicate tandem affinity purifications of each targeted yeast TAP-tagged mRNA translation protein coupled with multidimensional liquid chromatography and tandem mass spectrometry analysis are used to identify and quantify copurifying proteins. To improve sensitivity and minimize spurious, nonspecific interactions, a novel cross-validation approach is employed to identify the most statistically significant protein-protein interactions. Using experimental and computational strategies discussed herein, the previously described protein composition of the canonical eukaryotic mRNA translation initiation, elongation, and termination complexes is calculated. In addition, statistically significant unpublished protein interactions and phosphorylation sites for S. cerevisiae's mRNA translation proteins and complexes are identified.
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Affiliation(s)
- Andrew J Link
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Xinnan Niu
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Connie M Weaver
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Jennifer L Jennings
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Dexter T Duncan
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - K Jill McAfee
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Morgan Sammons
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Vince R Gerbasi
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Adam R Farley
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Tracey C Fleischer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | | | - Parimal Samir
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Allison Galassie
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Braden Boone
- Department of Bioinformatics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
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20
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Kashiwagi K, Yokoyama T, Nishimoto M, Takahashi M, Sakamoto A, Yonemochi M, Shirouzu M, Ito T. Structural basis for eIF2B inhibition in integrated stress response. Science 2019; 364:495-499. [PMID: 31048492 DOI: 10.1126/science.aaw4104] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/05/2019] [Indexed: 01/02/2023]
Abstract
A core event in the integrated stress response, an adaptive pathway common to all eukaryotic cells in response to various stress stimuli, is the phosphorylation of eukaryotic translation initiation factor 2 (eIF2). Normally, unphosphorylated eIF2 transfers the methionylated initiator tRNA to the ribosome in a guanosine 5'-triphosphate-dependent manner. By contrast, phosphorylated eIF2 inhibits its specific guanine nucleotide exchange factor, eIF2B. To elucidate how the eIF2 phosphorylation status regulates the eIF2B activity, we determined cryo-electron microscopic and crystallographic structures of eIF2B in complex with unphosphorylated or phosphorylated eIF2. The unphosphorylated and phosphorylated forms of eIF2 bind to eIF2B in completely different manners: the nucleotide exchange-active and -inactive modes, respectively. These structures explain how phosphorylated eIF2 dominantly inhibits the nucleotide exchange activity of eIF2B.
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Affiliation(s)
- Kazuhiro Kashiwagi
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takeshi Yokoyama
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Madoka Nishimoto
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mari Takahashi
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Ayako Sakamoto
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mayumi Yonemochi
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takuhiro Ito
- RIKEN Center for Biosystems Dynamics Research, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
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21
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Start Codon Recognition in Eukaryotic and Archaeal Translation Initiation: A Common Structural Core. Int J Mol Sci 2019; 20:ijms20040939. [PMID: 30795538 PMCID: PMC6412873 DOI: 10.3390/ijms20040939] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 01/12/2023] Open
Abstract
Understanding molecular mechanisms of ribosomal translation sheds light on the emergence and evolution of protein synthesis in the three domains of life. Universally, ribosomal translation is described in three steps: initiation, elongation and termination. During initiation, a macromolecular complex assembled around the small ribosomal subunit selects the start codon on the mRNA and defines the open reading frame. In this review, we focus on the comparison of start codon selection mechanisms in eukaryotes and archaea. Eukaryotic translation initiation is a very complicated process, involving many initiation factors. The most widespread mechanism for the discovery of the start codon is the scanning of the mRNA by a pre-initiation complex until the first AUG codon in a correct context is found. In archaea, long-range scanning does not occur because of the presence of Shine-Dalgarno (SD) sequences or of short 5′ untranslated regions. However, archaeal and eukaryotic translation initiations have three initiation factors in common: e/aIF1, e/aIF1A and e/aIF2 are directly involved in the selection of the start codon. Therefore, the idea that these archaeal and eukaryotic factors fulfill similar functions within a common structural ribosomal core complex has emerged. A divergence between eukaryotic and archaeal factors allowed for the adaptation to the long-range scanning process versus the SD mediated prepositioning of the ribosome.
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22
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Merrick WC, Pavitt GD. Protein Synthesis Initiation in Eukaryotic Cells. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a033092. [PMID: 29735639 DOI: 10.1101/cshperspect.a033092] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review summarizes our current understanding of the major pathway for the initiation phase of protein synthesis in eukaryotic cells, with a focus on recent advances. We describe the major scanning or messenger RNA (mRNA) m7G cap-dependent mechanism, which is a highly coordinated and stepwise regulated process that requires the combined action of at least 12 distinct translation factors with initiator transfer RNA (tRNA), ribosomes, and mRNAs. We limit our review to studies involving either mammalian or budding yeast cells and factors, as these represent the two best-studied experimental systems, and only include a reference to other organisms where particular insight has been gained. We close with a brief description of what we feel are some of the major unknowns in eukaryotic initiation.
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Affiliation(s)
- William C Merrick
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, United Kingdom
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23
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Causey DR, Pohl MAN, Stead DA, Martin SAM, Secombes CJ, Macqueen DJ. High-throughput proteomic profiling of the fish liver following bacterial infection. BMC Genomics 2018; 19:719. [PMID: 30285610 PMCID: PMC6167799 DOI: 10.1186/s12864-018-5092-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/19/2018] [Indexed: 02/07/2023] Open
Abstract
Background High-throughput proteomics was used to determine the role of the fish liver in defense responses to bacterial infection. This was done using a rainbow trout (Oncorhynchus mykiss) model following infection with Aeromonas salmonicida, the causative agent of furunculosis. The vertebrate liver has multifaceted functions in innate immunity, metabolism, and growth; we hypothesize this tissue serves a dual role in supporting host defense in parallel to metabolic adjustments that promote effective immune function. While past studies have reported mRNA responses to A. salmonicida in salmonids, the impact of bacterial infection on the liver proteome remains uncharacterized in fish. Results Rainbow trout were injected with A. salmonicida or PBS (control) and liver extracted 48 h later for analysis on a hybrid quadrupole-Orbitrap mass spectrometer. A label-free method was used for protein abundance profiling, which revealed a strong innate immune response along with evidence to support parallel rewiring of metabolic and growth systems. 3076 proteins were initially identified against all proteins (n = 71,293 RefSeq proteins) annotated in a single high-quality rainbow trout reference genome, of which 2433 were maintained for analysis post-quality filtering. Among the 2433 proteins, 109 showed significant differential abundance following A. salmonicida challenge, including many upregulated complement system and acute phase response proteins, in addition to molecules with putative functions that may support metabolic re-adjustments. We also identified novel expansions in the complement system due to gene and whole genome duplication events in salmonid evolutionary history, including eight C3 proteins showing differential changes in abundance. Conclusions This study provides the first high-throughput proteomic examination of the fish liver in response to bacterial challenge, revealing novel markers for the host defense response, and evidence of metabolic remodeling in conjunction with activation of innate immunity. Electronic supplementary material The online version of this article (10.1186/s12864-018-5092-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dwight R Causey
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Moritz A N Pohl
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - David A Stead
- Aberdeen Proteomics, University of Aberdeen, The Rowett Institute, Aberdeen, UK
| | | | | | - Daniel J Macqueen
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
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24
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Tucker EJ, Grover SR, Robevska G, van den Bergen J, Hanna C, Sinclair AH. Identification of variants in pleiotropic genes causing "isolated" premature ovarian insufficiency: implications for medical practice. Eur J Hum Genet 2018; 26:1319-1328. [PMID: 29706645 PMCID: PMC6117257 DOI: 10.1038/s41431-018-0140-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/25/2018] [Accepted: 03/13/2018] [Indexed: 11/09/2022] Open
Abstract
Next-generation sequencing (NGS) is increasingly being used in a clinical setting for the molecular diagnosis of patients with heterogeneous disorders, such as premature ovarian insufficiency (POI). We performed NGS of ~1000 candidate genes in four unrelated patients with POI. We discovered the genetic cause of "isolated" POI in two cases, both of which had causative variants in surprising genes. In the first case, a homozygous nonsense variant in NBN was causative. Recessive function-altering NBN variants typically cause Nijmegen breakage syndrome characterized by microcephaly, cancer predisposition, and immunodeficiency, none of which are evident in the patient. At a cellular level, we found evidence of chromosomal instability. In the second case, compound heterozygous variants in EIF2B2 were causative. Recessive EIF2B2 function-altering variants usually cause leukoencephalopathy with episodic decline. Subsequent MRI revealed subclinical neurological abnormalities. These cases demonstrate that variants in NBN and EIF2B2, which usually cause severe syndromes, can cause apparently isolated POI, and that (1) NGS can precede clinical diagnosis and guide patient management, (2) NGS can redefine the phenotypic spectrum of syndromes, and (3) NGS may make unanticipated diagnoses that must be sensitively communicated to patients. Although there is rigorous debate about the handling of secondary/incidental findings using NGS, there is little discussion of the management of causative pleiotropic gene variants that have broader implications than that for which genetic studies were sought.
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Affiliation(s)
- Elena J Tucker
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Sonia R Grover
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, 3052, Australia
- Department of Paediatric and Adolescent Gynaecology, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
| | - Gorjana Robevska
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
| | - Jocelyn van den Bergen
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
| | - Chloe Hanna
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
- Department of Paediatric and Adolescent Gynaecology, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
| | - Andrew H Sinclair
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia.
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, 3052, Australia.
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25
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Analysis of eIF2B bodies and their relationships with stress granules and P-bodies. Sci Rep 2018; 8:12264. [PMID: 30115954 PMCID: PMC6095920 DOI: 10.1038/s41598-018-30805-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 08/06/2018] [Indexed: 12/02/2022] Open
Abstract
Eukaryotic cells respond to stress and changes in the environment in part by repressing translation and forming cytoplasmic assemblies called stress granules and P-bodies, which harbor non-translating mRNAs and proteins. A third, but poorly understood, assembly called the eIF2B body can form and contains the eIF2B complex, an essential guanine exchange factor for the translation initiation factor eIF2. Hypomorphic EIF2B alleles can lead to Vanishing White Matter Disease (VWMD), a leukodystrophy that causes progressive white matter loss. An unexplored question is how eIF2B body formation is controlled and whether VWMD alleles in EIF2B alter the formation of eIF2B bodies, stress granules, or P-bodies. To examine these issues, we assessed eIF2B body, stress granule, and P-body induction in wild-type yeast cells and cells carrying VWMD alleles in the EIF2B2 (GCD7) and EIF2B5 (GCD6) subunits of eIF2B. We demonstrate eIF2B bodies are rapidly and reversibly formed independently of stress granules during acute glucose deprivation. VWMD mutations had diverse effects on stress-induced assemblies with some alleles altering eIF2B bodies, and others leading to increased P-body formation. Moreover, some VWMD-causing mutations in GCD7 caused hyper-sensitivity to chronic GCN2 activation, consistent with VWMD mutations causing hyper-sensitivity to eIF2α phosphorylation and thereby impacting VWMD pathogenesis.
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26
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Hughes D, Mallucci GR. The unfolded protein response in neurodegenerative disorders - therapeutic modulation of the PERK pathway. FEBS J 2018; 286:342-355. [PMID: 29476642 DOI: 10.1111/febs.14422] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/25/2018] [Accepted: 02/20/2018] [Indexed: 12/22/2022]
Abstract
The unfolded protein response (UPR) is a highly conserved protein quality control mechanism, activated in response to Endoplasmic Reticulum (ER) stress. Signalling is mediated through three branches, PERK, IRE1, and ATF6, respectively, that together provide a coordinated response that contributes to overcoming disrupted proteostasis. PERK branch activation predominantly causes a rapid reduction in global rates of translation, while the IRE1 and ATF6 branch signalling induce a transcriptional response resulting in expression of chaperones and components of the protein degradation machinery. Protein misfolding neurodegenerative diseases show disruption of proteostasis as a biochemical feature. In the brains of animal models of disease and in human post mortem tissue from many of these disorders, markers of UPR induction, particularly, the PERK pathway can be observed in close association with disease progression. Recent research has revealed dysregulated UPR signalling to be a major pathogenic mechanism in neurodegeneration, and that genetic and pharmacological modulation of the PERK pathway results in potent neuroprotection. Targeting aberrant UPR signalling is the focus of new therapeutic strategies, which importantly could be beneficial across the broad spectrum of neurodegenerative diseases.
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Affiliation(s)
| | - Giovanna R Mallucci
- MRC Toxicology Unit, Leicester, UK.,Department of Clinical Neurosciences, University of Cambridge, UK.,UK Dementia Research Institute, University of Cambridge, UK
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27
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Marques-Ramos A, Candeias MM, Menezes J, Lacerda R, Willcocks M, Teixeira A, Locker N, Romão L. Cap-independent translation ensures mTOR expression and function upon protein synthesis inhibition. RNA (NEW YORK, N.Y.) 2017; 23:1712-1728. [PMID: 28821580 PMCID: PMC5648038 DOI: 10.1261/rna.063040.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/15/2017] [Indexed: 06/07/2023]
Abstract
The mechanistic/mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase that integrates cellular signals from the nutrient and energy status to act, namely, on the protein synthesis machinery. While major advances have emerged regarding the regulators and effects of the mTOR signaling pathway, little is known about the regulation of mTOR gene expression. Here, we show that the human mTOR transcript can be translated in a cap-independent manner, and that its 5' untranslated region (UTR) is a highly folded RNA scaffold capable of binding directly to the 40S ribosomal subunit. We further demonstrate that mTOR is able to bypass the cap requirement for translation both in normal and hypoxic conditions. Moreover, our data reveal that the cap-independent translation of mTOR is necessary for its ability to induce cell-cycle progression into S phase. These results suggest a novel regulatory mechanism for mTOR gene expression that integrates the global protein synthesis changes induced by translational inhibitory conditions.
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Affiliation(s)
- Ana Marques-Ramos
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Marco M Candeias
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Juliane Menezes
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Rafaela Lacerda
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Margaret Willcocks
- Microbial and Cellular Sciences Department, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7TE, United Kingdom
| | - Alexandre Teixeira
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
| | - Nicolas Locker
- Microbial and Cellular Sciences Department, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7TE, United Kingdom
| | - Luísa Romão
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, 1649-016 Lisboa, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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28
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Raini G, Sharet R, Herrero M, Atzmon A, Shenoy A, Geiger T, Elroy-Stein O. Mutant eIF2B leads to impaired mitochondrial oxidative phosphorylation in vanishing white matter disease. J Neurochem 2017; 141:694-707. [PMID: 28306143 DOI: 10.1111/jnc.14024] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 12/14/2022]
Abstract
Eukaryotic translation initiation factor 2B (eIF2B) is a master regulator of protein synthesis under normal and stress conditions. Mutations in any of the five genes encoding its subunits lead to vanishing white matter (VWM) disease, a recessive genetic deadly illness caused by progressive loss of white matter in the brain. In this study we used fibroblasts, which are not involved in the disease, to demonstrate the involvement of eIF2B in mitochondrial function and abundance. Mass spectrometry of total proteome of mouse embryonic fibroblasts (MEFs) isolated from Eif2b5R132H/R132H mice revealed unbalanced stoichiometry of proteins involved in oxidative phosphorylation and of mitochondrial translation machinery components, among others. Mutant MEFs exhibit 55% decrease in oxygen consumption rate per mtDNA content and 47% increase in mitochondrial abundance (p < 0.005), reflecting adaptation to energy requirements. A more robust eIF2B-associated oxidative respiration deficiency was found in mutant primary astrocytes, which exhibit > 3-fold lower ATP-linked respiration per cell despite a 2-fold increase in mtDNA content (p < 0.03). The 2-fold increase in basal and stimulated glycolysis in mutant astrocytes (p ≤ 0.03), but not in MEFs, demonstrates their higher energetic needs and further explicates their involvement in the disease. The data demonstrate the critical role of eIF2B in tight coordination of expression from nuclear and mitochondrial genomes and illuminates the importance of mitochondrial function in VWM pathology. Further dissection of the signaling network associated with eIF2B function will help generating therapeutic strategies for VWM disease and possibly other neurodegenerative disorders.
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Affiliation(s)
- Gali Raini
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Reut Sharet
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Melisa Herrero
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Andrea Atzmon
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Anjana Shenoy
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tamar Geiger
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Elroy-Stein
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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29
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Jennings MD, Kershaw CJ, Adomavicius T, Pavitt GD. Fail-safe control of translation initiation by dissociation of eIF2α phosphorylated ternary complexes. eLife 2017; 6:e24542. [PMID: 28315520 PMCID: PMC5404910 DOI: 10.7554/elife.24542] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/16/2017] [Indexed: 01/21/2023] Open
Abstract
Phosphorylation of eIF2α controls translation initiation by restricting the levels of active eIF2-GTP/Met-tRNAi ternary complexes (TC). This modulates the expression of all eukaryotic mRNAs and contributes to the cellular integrated stress response. Key to controlling the activity of eIF2 are translation factors eIF2B and eIF5, thought to primarily function with eIF2-GDP and TC respectively. Using a steady-state kinetics approach with purified proteins we demonstrate that eIF2B binds to eIF2 with equal affinity irrespective of the presence or absence of competing guanine nucleotides. We show that eIF2B can compete with Met-tRNAi for eIF2-GTP and can destabilize TC. When TC is formed with unphosphorylated eIF2, eIF5 can out-compete eIF2B to stabilize TC/eIF5 complexes. However when TC/eIF5 is formed with phosphorylated eIF2, eIF2B outcompetes eIF5 and destabilizes TC. These data uncover competition between eIF2B and eIF5 for TC and identify that phosphorylated eIF2-GTP translation initiation intermediate complexes can be inhibited by eIF2B.
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Affiliation(s)
- Martin D Jennings
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Christopher J Kershaw
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Tomas Adomavicius
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
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30
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Betteridge ZE, Woodhead F, Lu H, Shaddick G, Bunn CC, Denton CP, Abraham DJ, du Bois RM, Lewis M, Wells AU, McHugh NJ. Brief Report: Anti-Eukaryotic Initiation Factor 2B Autoantibodies Are Associated With Interstitial Lung Disease in Patients With Systemic Sclerosis. Arthritis Rheumatol 2016; 68:2778-2783. [PMID: 27273608 DOI: 10.1002/art.39755] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 05/10/2016] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Hui Lu
- University of Bath; Bath UK
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31
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eIF2B: recent structural and functional insights into a key regulator of translation. Biochem Soc Trans 2016; 43:1234-40. [PMID: 26614666 DOI: 10.1042/bst20150164] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The eukaryotic translation initiation factor (eIF) eIF2B is a key regulator of mRNA translation, being the guanine nt exchange factor (GEF) responsible for the recycling of the heterotrimeric G-protein, eIF2, which is required to allow translation initiation to occur. Unusually for a GEF, eIF2B is a multi-subunit protein, comprising five different subunits termed α through ε in order of increasing size. eIF2B is subject to tight regulation in the cell and may also serve additional functions. Here we review recent insights into the subunit organization of the mammalian eIF2B complex, gained both from structural studies of the complex and from studies of mutations of eIF2B that result in the neurological disorder leukoencephalopathy with vanishing white matter (VWM). We will also discuss recent data from yeast demonstrating a novel function of the eIF2B complex key for translational regulation.
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32
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Jennings MD, Kershaw CJ, White C, Hoyle D, Richardson JP, Costello JL, Donaldson IJ, Zhou Y, Pavitt GD. eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control. Nucleic Acids Res 2016; 44:9698-9709. [PMID: 27458202 PMCID: PMC5175340 DOI: 10.1093/nar/gkw657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 01/10/2023] Open
Abstract
In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2β that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2β mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2β mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2•GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2β acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation.
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Affiliation(s)
- Martin D Jennings
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Christopher J Kershaw
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Christopher White
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Danielle Hoyle
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Jonathan P Richardson
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Joseph L Costello
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Ian J Donaldson
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Yu Zhou
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Graham D Pavitt
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
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33
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Chen N, Dai L, Jiang Y, Wang J, Hao H, Ren Y, Leng X, Zang L, Wu Y. Endoplasmic reticulum stress intolerance in EIF2B3 mutant oligodendrocytes is modulated by depressed autophagy. Brain Dev 2016; 38:507-15. [PMID: 26625702 DOI: 10.1016/j.braindev.2015.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 10/06/2015] [Accepted: 11/06/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Eukaryotic translation initiation factor 2B (eIF2B) is an essential factor for the initiation of protein synthesis. Mutations in eIF2B encoded by EIF2B1-5 cause a lethal leukoencephalopathy--vanishing white matter disease (VWM). Previous studies have suggested that an improper activated unfolded protein response (UPR) after endoplasmic reticulum stress (ERS) contributed to the pathogenesis of the disease. Autophagy, an important compensatory pathway after ERS, was analyzed in this study. METHODS To determine the tolerance differences to ERS, cell viability and apoptosis rates were detected in oligodendrocyte cell lines transfected with EIF2B3-c.1037T>C or the wild type. Autophagy flux was measured between groups. Autophagy inducers and inhibitors were used to identify the role of autophagy in the mutant oligodendrocytes. RESULTS We confirmed that oligodendrocytes with mutant EIF2B3 was less tolerant to ERS than the wild type, with decreased cell viability and increased apoptosis rates. Autophagy flux was depressed in mutant oligodendrocytes under baseline condition and after ERS stimulation. Reduced expression of autophagy related gene (Atg) 3 and Atg 7 were involved in the depression of autophagy flux. The mutant oligodendrocytes pretreated with autophagy inducers showed stable cell viability and decreased apoptosis despite ERS induction, whereas the autophagy inhibitors aggravated cell apoptosis and viability declination. CONCLUSIONS Oligodendrocytes transfected with mutant EIF2B3 was less tolerant to ERS than the wild type. Depressed autophagy flux was observed in the mutant cells at baseline and after ERS stimulation. Improperly depressed autophagy played a role in the susceptibility to ERS in EIF2B3 mutant oligodendrocytes.
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Affiliation(s)
- Na Chen
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Lifang Dai
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Hongjun Hao
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yali Ren
- Lab of Electron Microscopy, Peking University First Hospital, Beijing 100034, China
| | - Xuerong Leng
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Lili Zang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
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Kashiwagi K, Shigeta T, Imataka H, Ito T, Yokoyama S. Expression, purification, and crystallization of Schizosaccharomyces pombe eIF2B. ACTA ACUST UNITED AC 2016; 17:33-8. [PMID: 27023709 PMCID: PMC4833825 DOI: 10.1007/s10969-016-9203-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/16/2016] [Indexed: 11/24/2022]
Abstract
Tight control of protein synthesis is necessary for cells to respond and adapt to environmental changes rapidly. Eukaryotic translation initiation factor (eIF) 2B, the guanine nucleotide exchange factor for eIF2, is a key target of translation control at the initiation step. The nucleotide exchange activity of eIF2B is inhibited by the stress-induced phosphorylation of eIF2. As a result, the level of active GTP-bound eIF2 is lowered, and protein synthesis is attenuated. eIF2B is a large multi-subunit complex composed of five different subunits, and all five of the subunits are the gene products responsible for the neurodegenerative disease, leukoencephalopathy with vanishing white matter. However, the overall structure of eIF2B has remained unresolved, due to the difficulty in preparing a sufficient amount of the eIF2B complex. To overcome this problem, we established the recombinant expression and purification method for eIF2B from the fission yeast Schizosaccharomyces pombe. All five of the eIF2B subunits were co-expressed and reconstructed into the complex in Escherichia coli cells. The complex was successfully purified with a high yield. This recombinant eIF2B complex contains each subunit in an equimolar ratio, and the size exclusion chromatography analysis suggests it forms a heterodecamer, consistent with recent reports. This eIF2B increased protein synthesis in the reconstituted in vitro human translation system. In addition, disease-linked mutations led to subunit dissociation. Furthermore, we crystallized this functional recombinant eIF2B, and the crystals diffracted to 3.0 Å resolution.
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Affiliation(s)
- Kazuhiro Kashiwagi
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.,RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Tomoaki Shigeta
- Graduate School of Engineering, University of Hyogo, Himeji, 671-2280, Japan
| | - Hiroaki Imataka
- Graduate School of Engineering, University of Hyogo, Himeji, 671-2280, Japan
| | - Takuhiro Ito
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. .,RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan. .,RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
| | - Shigeyuki Yokoyama
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. .,RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan. .,RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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Guo X, Snider WD, Chen B. GSK3β regulates AKT-induced central nervous system axon regeneration via an eIF2Bε-dependent, mTORC1-independent pathway. eLife 2016; 5:e11903. [PMID: 26974342 PMCID: PMC4805534 DOI: 10.7554/elife.11903] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 02/26/2016] [Indexed: 01/03/2023] Open
Abstract
Axons fail to regenerate after central nervous system (CNS) injury. Modulation of the PTEN/mTORC1 pathway in retinal ganglion cells (RGCs) promotes axon regeneration after optic nerve injury. Here, we report that AKT activation, downstream of Pten deletion, promotes axon regeneration and RGC survival. We further demonstrate that GSK3β plays an indispensable role in mediating AKT-induced axon regeneration. Deletion or inactivation of GSK3β promotes axon regeneration independently of the mTORC1 pathway, whereas constitutive activation of GSK3β reduces AKT-induced axon regeneration. Importantly, we have identified eIF2Bε as a novel downstream effector of GSK3β in regulating axon regeneration. Inactivation of eIF2Bε reduces both GSK3β and AKT-mediated effects on axon regeneration. Constitutive activation of eIF2Bε is sufficient to promote axon regeneration. Our results reveal a key role of the AKT-GSK3β-eIF2Bε signaling module in regulating axon regeneration in the adult mammalian CNS. DOI:http://dx.doi.org/10.7554/eLife.11903.001 The central nervous system consists of the neurons that make up the brain, retina, and spinal cord. Neurons transmit electrical signals along a cable-like structure called an axon. However, an axon cannot regenerate itself, and so injuries that crush or sever the axons can lead to permanent damage. This happens for two reasons: neurons don’t have the same regenerative ability as other cells, and the environment in the central nervous system restricts cell growth. The optic nerve transmits visual information from the eye to the brain. Studies in mice with a damaged optic nerve show that it is possible to regenerate the axons of neurons that lack a protein known as PTEN. These studies revealed one molecular pathway by which eliminating PTEN helps to boost the regrowth of axons. Now, Guo et al. identify another independent pathway by which eliminating PTEN helps promote axon regeneration in damaged mouse optic nerves. This pathway starts with a growth-promoting enzyme called AKT, which is turned on in neurons that lack PTEN. Indeed, injecting mice with an active form of this enzyme caused the optic nerve fiber to regrow in mice whose optic nerve had been crushed. Further experiments revealed that AKT activates a pathway in which another enzyme called GSK3β acts on a protein called eIF2Bε. A future challenge is to simultaneously manipulate the different signaling pathways that have been linked to axon regrowth to investigate whether this combined approach could help repair damage to the central nervous system. DOI:http://dx.doi.org/10.7554/eLife.11903.002
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Affiliation(s)
- Xinzheng Guo
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, United States
| | - William D Snider
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Bo Chen
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, United States.,Department of Neurobiology, Yale University School of Medicine, New Haven, United States
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Crystal structure of eukaryotic translation initiation factor 2B. Nature 2016; 531:122-5. [DOI: 10.1038/nature16991] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/12/2016] [Indexed: 12/15/2022]
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Stoichiometry of the eIF2B complex is maintained by mutual stabilization of subunits. Biochem J 2015; 473:571-80. [PMID: 26614765 DOI: 10.1042/bj20150828] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/26/2015] [Indexed: 12/30/2022]
Abstract
The eukaryotic translation initiation factor eIF2B is a multi-subunit complex with a crucial role in the regulation of global protein synthesis in the cell. The complex comprises five subunits, termed α through ε in order of increasing size, arranged as a heterodecamer with two copies of each subunit. Regulation of the co-stoichiometric expression of the eIF2B subunits is crucial for the proper function and regulation of the eIF2B complex in cells. We have investigated the control of stoichiometric eIF2B complexes through mutual stabilization of eIF2B subunits. Our data show that the stable expression of the catalytic eIF2Bε subunit in human cells requires co-expression of eIF2Bγ. Similarly, stable expression of eIF2Bδ requires both eIF2Bβ and eIF2Bγ+ε. The expression of these subunits decreases despite there being no change in either the levels or the translation of their mRNAs. Instead, these subunits are targeted for degradation by the ubiquitin-proteasome system. The data allow us to propose a model for the formation of stoichiometric eIF2B complexes which can ensure their stoichiometric incorporation into the holocomplex.
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Palmesino E, Apuzzo T, Thelen S, Mueller B, Langen H, Thelen M. Association of eukaryotic translation initiation factor eIF2B with fully solubilized CXCR4. J Leukoc Biol 2015; 99:971-8. [PMID: 26609049 DOI: 10.1189/jlb.2ma0915-415r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/31/2015] [Indexed: 12/31/2022] Open
Abstract
Chemokine receptors are key regulators of leukocyte trafficking but also have an important role in development, tumor growth, and metastasis. Among the chemokine receptors, CXCR4 is the only one that leads to perinatal death when genetically ablated in mice, indicating a more-widespread function in development. To identify pathways that are activated downstream of CXCR4, a solubilization protocol was elaborated, which allows for the isolation of the endogenous receptor from human cells in its near-native conformation. Solubilized CXCR4 is recognized by the conformation-sensitive monoclonal antibody 12G5 and retains the ability to bind CXCL12 in solution, which was abolished in the presence of receptor antagonists. Mass spectrometry of CXCR4 immunoprecipitates revealed a specific interaction with the pentameric eukaryotic translation initiation factor 2B. The observation that the addition of CXCL12 leads to the dissociation of eukaryotic translation initiation factor 2B from CXCR4 suggests that stimulation of the receptor may trigger the local protein synthesis required for efficient cell movement.
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Affiliation(s)
- Elena Palmesino
- Institute for Research in Biomedicine, Bellinzona, Switzerland; and
| | - Tiziana Apuzzo
- Institute for Research in Biomedicine, Bellinzona, Switzerland; and
| | - Sylvia Thelen
- Institute for Research in Biomedicine, Bellinzona, Switzerland; and
| | - Bernd Mueller
- Protein and Metabolite Technologies, F. Hoffmann-La Roche Ltd, Pharmaceutical Sciences Roche Innovation Center, Basel, Switzerland
| | - Hanno Langen
- Protein and Metabolite Technologies, F. Hoffmann-La Roche Ltd, Pharmaceutical Sciences Roche Innovation Center, Basel, Switzerland
| | - Marcus Thelen
- Institute for Research in Biomedicine, Bellinzona, Switzerland; and
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Mutations in the genes encoding eukaryotic translation initiation factor 2B in Japanese patients with vanishing white matter disease. Brain Dev 2015; 37:960-6. [PMID: 25843247 DOI: 10.1016/j.braindev.2015.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 03/04/2015] [Accepted: 03/19/2015] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Vanishing white matter disease (VWM) is a chronic, progressive leukoencephalopathy associated with episodes of rapid deterioration following minor stress events such as head traumas or infectious disorders. The white matter of the patients with VWM exhibits characteristic radiological findings. METHOD The genes encoding all five subunits of eukaryotic translation initiation factor 2B (EIF2B) were analyzed in patients, who were tentatively diagnosed with VWM, by Sanger sequencing. RESULTS Seven mutations were identified in the genes encoding the subunits 1, 2, 4, and 5 of EIF2B. Among them, one mutation (p.V83E) in the subunit 2 (EIF2B2) was recurrently identified in three alleles, indicating the most common mutation in Japanese patients with VWM. Two patients were homozygous, and the other four patients were compound heterozygous. CONCLUSION All patients showed white matter abnormalities with various degrees. One patient showed manifestations of end-stage VWM disease. Some patients showed late onset and slow progression associated with brain magnetic resonance imaging displaying T2 high intensity only in the deep white matter. There was clinical heterogeneity among patients with VWM.
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Kuhle B, Eulig NK, Ficner R. Architecture of the eIF2B regulatory subcomplex and its implications for the regulation of guanine nucleotide exchange on eIF2. Nucleic Acids Res 2015; 43:9994-10014. [PMID: 26384431 PMCID: PMC4787765 DOI: 10.1093/nar/gkv930] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/07/2015] [Indexed: 11/14/2022] Open
Abstract
Eukaryal translation initiation factor 2B (eIF2B) acts as guanine nucleotide exchange factor (GEF) for eIF2 and forms a central target for pathways regulating global protein synthesis. eIF2B consists of five non-identical subunits (α-ϵ), which assemble into a catalytic subcomplex (γ, ϵ) responsible for the GEF activity, and a regulatory subcomplex (α, β, δ) which regulates the GEF activity under stress conditions. Here, we provide new structural and functional insight into the regulatory subcomplex of eIF2B (eIF2B(RSC)). We report the crystal structures of eIF2Bβ and eIF2Bδ from Chaetomium thermophilum as well as the crystal structure of their tetrameric eIF2B(βδ)2 complex. Combined with mutational and biochemical data, we show that eIF2B(RSC) exists as a hexamer in solution, consisting of two eIF2Bβδ heterodimers and one eIF2Bα2 homodimer, which is homologous to homohexameric ribose 1,5-bisphosphate isomerases. This homology is further substantiated by the finding that eIF2Bα specifically binds AMP and GMP as ligands. Based on our data, we propose a model for eIF2B(RSC) and its interactions with eIF2 that is consistent with previous biochemical and genetic data and provides a framework to better understand eIF2B function, the molecular basis for Gcn(-), Gcd(-) and VWM/CACH mutations and the evolutionary history of the eIF2B complex.
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Affiliation(s)
- Bernhard Kuhle
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Nora K Eulig
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Ralf Ficner
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
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Gogoi P, Srivastava A, Jayaprakash P, Jeyakanthan J, Kanaujia SP. In silico analysis suggests that PH0702 and PH0208 encode for methylthioribose-1-phosphate isomerase and ribose-1,5-bisphosphate isomerase, respectively, rather than aIF2Bβ and aIF2Bδ. Gene 2015; 575:118-26. [PMID: 26318479 DOI: 10.1016/j.gene.2015.08.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/02/2015] [Accepted: 08/23/2015] [Indexed: 12/21/2022]
Abstract
The overall process of protein biosynthesis across all domains of life is similar; however, detailed insights reveal a range of differences in the proteins involved. For decades, the process of protein translation in archaea has been considered to be closer to eukaryotes than to bacteria. In archaea, however, several homologues of eukaryotic proteins involved in translation initiation have not yet been identified; one of them being the initiation factor eIF2B consisting of five subunits (α, β, γ, δ and ε). Three open reading frames (PH0440, PH0702 and PH0208) in Pyrococcus horikoshii have been proposed to encode for the α-, β- and δ-subunits of aIF2B, respectively. The crystal structure of PH0440 shows similarity toward the α-subunit of eIF2B. However, the capability of PH0702 and PH0208 to function as the β- and δ-subunits of eIF2B, respectively, remains uncertain. In this study, we have taken up the task of annotating PH0702 and PH0208 using bioinformatics methods. The phylogenetic analysis of protein sequences belonging to IF2B-like family along with PH0702 and PH0208 revealed that PH0702 belonged to methylthioribose-1-phosphate isomerase (MTNA) group of proteins, whereas, PH0208 was found to be clustered in the group of ribose-1,5-bisphosphate isomerase (R15PI) proteins. A careful analysis of protein sequences and structures available for eIF2B, MTNA and R15PI confirms that PH0702 and PH0208 contain residues essential for the enzymatic activity of MTNA and R15PI, respectively. Additionally, the protein PH0208 comprises of the residues required for the dimer formation which is essential for the biological activity of R15PI. This prompted us to examine all eIF2B-like proteins from archaea and to annotate their function. The results reveal that majority of these proteins are homologues of the α-subunit of eIF2B, even though they lack the residues essential for their functional activity. A better understanding of the mechanism of GTP exchange during translation initiation in archaea is henceforth required.
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Affiliation(s)
- Prerana Gogoi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Ambuj Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Prajisha Jayaprakash
- Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Jeyaraman Jeyakanthan
- Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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eIF2 interactions with initiator tRNA and eIF2B are regulated by post-translational modifications and conformational dynamics. Cell Discov 2015; 1:15020. [PMID: 27462419 PMCID: PMC4860841 DOI: 10.1038/celldisc.2015.20] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/12/2015] [Indexed: 12/18/2022] Open
Abstract
Translation of messenger RNA (mRNA) into proteins is key to eukaryotic gene expression and begins when initiation factor-2 (eIF2) delivers methionyl initiator tRNA (Met-tRNAiMet) to ribosomes. This first step is controlled by eIF2B mediating guanine nucleotide exchange on eIF2. We isolated eIF2 from yeast and used mass spectrometry to study the intact complex, and found that eIF2β is the most labile of the three subunits (eIF2α/β/γ). We then compared conformational dynamics of the ternary complex eIF2:GTP:Met-tRNAiMet with apo eIF2 using comparative chemical cross-linking. Results revealed high conformational dynamics for eIF2α in apo eIF2 while in the ternary complex all three subunits are constrained. Novel post-translational modifications identified here in both eIF2 and eIF2B were combined with established sites, and located within protein sequences and homology models. We found clustering at subunit interfaces and highly phosphorylated unstructured regions, at the N-terminus of eIF2β, and also between the eIF2Bε core and catalytic domains. We propose that modifications of these unstructured regions have a key role in regulating interactions between eIF2 and eIF2B, as well as other eIFs.
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Zhang H, Dai L, Chen N, Zang L, Leng X, Du L, Wang J, Jiang Y, Zhang F, Wu X, Wu Y. Fifteen novel EIF2B1-5 mutations identified in Chinese children with leukoencephalopathy with vanishing white matter and a long term follow-up. PLoS One 2015; 10:e0118001. [PMID: 25761052 PMCID: PMC4356545 DOI: 10.1371/journal.pone.0118001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/03/2015] [Indexed: 01/08/2023] Open
Abstract
Leukoencephalopathy with vanishing white matter (VWM) is one of the most prevalent inherited childhood white matter disorders, which caused by mutations in each of the five subunits of eukaryotic translation initiation factor 2B (EIF2B1-5). In our study, 34 out of the 36 clinically diagnosed children (94%) were identified to have EIF2B1-5 mutations by sequencing. 15 novel mutations were identified. CNVs were not detected in patients with only one mutant allele and mutation-negative determined by gene sequencing. There is a significantly higher incidence of patients with EIF2B3 mutations compared with Caucasian patients (32% vs. 4%). c.1037T>C (p.Ile346Thr) in EIF2B3 was confirmed to be a founder mutation in Chinese, which probably one of the causes of the genotypic differences between ethnicities. Our average 4.4 years-follow-up on infantile, early childhood and juvenile VWM children suggested a rapid deterioration in motor function. Episodic aggravation was presented in 90% of infantile cases and 71.4% of childhood cases. 10 patients died during the follow-up. The Kaplan-Meier curve showed that the median survival time is 8.83 ± 1.51 years. This is the largest sample of children in a VWM follow-up study, which is helpful for a more depth understanding about the natural course.
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Affiliation(s)
- Haihua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Lifang Dai
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Na Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Lili Zang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xuerong Leng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Li Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Feng Zhang
- School of Life Sciences, Fudan University, Shanghai, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- * E-mail:
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Wei C, Lin M, Jinjun B, Su F, Dan C, Yan C, Jie Y, Jin Z, Zi-Chun H, Wu Y. Involvement of general control nonderepressible kinase 2 in cancer cell apoptosis by posttranslational mechanisms. Mol Biol Cell 2015; 26:1044-57. [PMID: 25589675 PMCID: PMC4357505 DOI: 10.1091/mbc.e14-10-1438] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
GCN2 exerts its proapoptotic function in cancer cell death by posttranslational mechanisms. Modulation of GCN2 expression can be used for molecular targeted cancer therapy and drug development. Na+,K+-ATPase ligands are the first identified small-molecule drugs that can trigger cancer cell death by modulating GCN2 signaling. General control nonderepressible kinase 2 (GCN2) is a promising target for cancer therapy. However, the role of GCN2 in cancer cell survival or death is elusive; further, small molecules targeting GCN2 signaling are not available. By using a GCN2 level-based drug screening assay, we found that GCN2 protein level critically determined the sensitivity of the cancer cells toward Na+,K+-ATPase ligand–induced apoptosis both in vitro and in vivo, and this effect was largely dependent on C/EBP homologous protein (CHOP) induction. Further analysis revealed that GCN2 is a short-lived protein. In A549 lung carcinoma cells, cellular β-arrestin1/2 associated with GCN2 and maintained the GCN2 protein level at a low level by recruiting the E3 ligase NEDD4L and facilitating consequent proteasomal degradation. However, Na+,K+-ATPase ligand treatment triggered the phosphorylation of GCN2 at threonine 899, which increased the GCN2 protein level by disrupting the formation of GCN2–β-arrestin–NEDD4L ternary complex. The enhanced GCN2 level, in turn, aggravated Na+,K+-ATPase ligand–induced cancer cell apoptosis. Our findings reveal that GCN2 can exert its proapoptotic function in cancer cell death by posttranslational mechanisms. Moreover, Na+,K+-ATPase ligands emerge as the first identified small-molecule drugs that can trigger cancer cell death by modulating GCN2 signaling.
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Affiliation(s)
- Chen Wei
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China State Key Lab of Natural Medicines, China Pharmaceutical University, Nanjing 210017, China
| | - Ma Lin
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Bian Jinjun
- Department of Anaesthesiology and Intensive Care Unit, Changhai Hospital, Affiliated Hospital of the Second Military Medical University, Shanghai 200433, China
| | - Feng Su
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Cao Dan
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Chen Yan
- Department of Chinese Medicine, Jiangsu Cancer Hospital, Nanjing 210009, China
| | - Yang Jie
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Zhang Jin
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Hua Zi-Chun
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China State Key Lab of Natural Medicines, China Pharmaceutical University, Nanjing 210017, China
| | - Yin Wu
- State Key Lab of Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China State Key Lab of Natural Medicines, China Pharmaceutical University, Nanjing 210017, China
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Gordiyenko Y, Schmidt C, Jennings MD, Matak-Vinkovic D, Pavitt GD, Robinson CV. eIF2B is a decameric guanine nucleotide exchange factor with a γ2ε2 tetrameric core. Nat Commun 2014; 5:3902. [PMID: 24852487 PMCID: PMC4046112 DOI: 10.1038/ncomms4902] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/15/2014] [Indexed: 01/21/2023] Open
Abstract
eIF2B facilitates and controls protein synthesis in eukaryotes by mediating guanine nucleotide exchange on its partner eIF2. We combined mass spectrometry (MS) with chemical cross-linking, surface accessibility measurements and homology modelling to define subunit stoichiometry and interactions within eIF2B and eIF2. Although it is generally accepted that eIF2B is a pentamer of five non-identical subunits (α–ε), here we show that eIF2B is a decamer. MS and cross-linking of eIF2B complexes allows us to propose a model for the subunit arrangements within eIF2B where the subunit assembly occurs through catalytic γ- and ε-subunits, with regulatory subunits arranged in asymmetric trimers associated with the core. Cross-links between eIF2 and eIF2B allow modelling of interactions that contribute to nucleotide exchange and its control by eIF2 phosphorylation. Finally, we identify that GTP binds to eIF2Bγ, prompting us to propose a multi-step mechanism for nucleotide exchange. Eukaryotic Initiation Factor 2 (eIF2) initiates protein synthesis aided by its partner eIF2B, which stimulates guanine nucleotide exchange on eIF2. Here, Gordiyenko et al. show that eIF2B exists as a decamer and propose a model for its subunit arrangement that provides new insight into its function.
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Affiliation(s)
- Yuliya Gordiyenko
- 1] Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK [2] MRC Laboratory of Molecular Biology, University of Cambridge, Francis Crick Avenue, Cambridge CB2 0QH, UK [3]
| | - Carla Schmidt
- 1] Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK [2]
| | - Martin D Jennings
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Dijana Matak-Vinkovic
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Graham D Pavitt
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
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Wortham NC, Martinez M, Gordiyenko Y, Robinson CV, Proud CG. Analysis of the subunit organization of the eIF2B complex reveals new insights into its structure and regulation. FASEB J 2014; 28:2225-37. [DOI: 10.1096/fj.13-243329] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Noel C. Wortham
- Centre for Biological SciencesUniversity of SouthamptonSouthamptonUK
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Abstract
Amino acids are the precursors for the synthesis of proteins. In humans, approximately half of the 20 different amino acids are essential, ie, must be obtained from the diet. Cells must therefore take account of amino acid availability to achieve sustainable rates of protein synthesis. One of the major mechanisms involved in this is signaling through a complex of proteins termed mammalian target of rapamycin complex (mTORC) 1, which is activated by amino acids. In turn, mTORC1 regulates the production of ribosomes, the molecular machines that make proteins, and the activity of other cellular components required for protein synthesis. mTORC1 signaling promotes the transcription of the genes for ribosomal RNAs and many other components involved in ribosome production. It also positively regulates the translation of the messenger RNAs (mRNAs) for ribosomal proteins. Indeed, recent studies have shown that mammalian target of rapamycin signaling drives the translation of mRNAs for many anabolic enzymes and other proteins involved in diverse cellular functions. The translational machinery is also regulated by the absence of amino acids through the protein kinase GCN2 (general control nonrepressed 2), which phosphorylates and in end-effect inhibits the translation initiation factor eIF2 (eukaryotic initiation factor 2). This process shuts down general protein synthesis to conserve amino acids.
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Affiliation(s)
- Christopher G Proud
- Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
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Weiss CS, Ochs MM, Hagenmueller M, Streit MR, Malekar P, Riffel JH, Buss SJ, Weiss KH, Sadoshima J, Katus HA, Hardt SE. DYRK2 negatively regulates cardiomyocyte growth by mediating repressor function of GSK-3β on eIF2Bε. PLoS One 2013; 8:e70848. [PMID: 24023715 PMCID: PMC3762802 DOI: 10.1371/journal.pone.0070848] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 06/26/2013] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND A prerequisite of hypertrophic response of the myocardium is an increase in protein synthesis. A central regulator of translation initiation is Eukaryotic initiation factor 2B (eIF2B). Here we assessed the hypothesis that regulation of protein synthesis via eIF2Bε is essential to cardiac hypertrophic response in vivo. METHODS Two transgenic mouse lines were generated with cardiac restricted overexpression of eIF2Bε or its mutant eIF2Bε-eIFS(535)A, which cannot be inactivated by phosphorylation through GSK-3β. RESULTS (1) Under baseline conditions eIF2Bε transgenic mice showed no difference in cardiac phenotype compared to wild type, whereas in the mutant eIF2Bε-S(535)A an increase in LV/tibia length (7.5 ± 0.4 mg/mm vs. 6.2 ± 0.2 mg/mm, p<0.001) and cardiomyocyte cross sectional area (13004 ± 570 vs. 10843 ± 347 RU, p<0.01) was observed. (2) Cardiac overexpression of eIF2Bε did not change the response of the heart to pathologic stress induced by chronic isoproterenol treatment. (3) Cardiac overexpression of the eIF2Bε transgene was followed by overexpression of DYRK2 which is known to prime the inhibitory action of GSK-3β on eIF2Bε, while DYRK1A and GSK-3β itself were not increased. (4) In C57BL/6 mice after 48 h of isoproterenol-stimulation or aortic banding, eIF2Bε was increased and DYRK2 was concomitantly decreased. (5) In line with these in vivo findings, siRNA knockdown of DYRK2 in cultured cardiomyocytes resulted in decreased levels of p(S535)- eIF2Bε, (6) whereas adenoviral induced overexpression of DYRK2 was accompanied by clearly increased phosphorylation of eIF2Bε, indicating a coordinated response pattern (7) Adenoviral induced overexpression of DYRK2 leads to significantly reduced cardiomyocyte size and diminishes hypertrophic response to adrenergic stimulation. CONCLUSIONS The interaction of GSK-3β and its priming kinase DYRK2 regulate the activity of eIF2Bε in cardiac myocytes. DYRK2 is a novel negative regulator of cardiomyocyte growth. DYRK2 could serve as a therapeutic option to regulate myocardial growth.
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Affiliation(s)
- Celine S. Weiss
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Marco M. Ochs
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Marco Hagenmueller
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Marcus R. Streit
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Pratima Malekar
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Johannes H. Riffel
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Sebastian J. Buss
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Karl H. Weiss
- Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Junichi Sadoshima
- New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Hugo A. Katus
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
| | - Stefan E. Hardt
- Internal Medicine III, University Hospital Heidelberg and DZHK (German Center for Cardiovascular Research), Heidelberg, Germany
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A yeast purification system for human translation initiation factors eIF2 and eIF2Bε and their use in the diagnosis of CACH/VWM disease. PLoS One 2013; 8:e53958. [PMID: 23335982 PMCID: PMC3545922 DOI: 10.1371/journal.pone.0053958] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 12/04/2012] [Indexed: 11/19/2022] Open
Abstract
Recessive inherited mutations in any of five subunits of the general protein synthesis factor eIF2B are responsible for a white mater neurodegenerative disease with a large clinical spectrum. The classical form is called Childhood Ataxia with CNS hypomyelination (CACH) or Vanishing White Matter Leukoencephalopathy (VWM). eIF2B-related disorders affect glial cells, despite the fact that eIF2B is a ubiquitous protein that functions as a guanine-nucleotide exchange factor (GEF) for its partner protein eIF2 in the translation initiation process in all eukaryotic cells. Decreased eIF2B activity measured by a GEF assay in patients' immortalised lymphocytic cells provides a biochemical diagnostic assay but is limited by the availability of eIF2 protein, which is classically purified from a mammalian cell source by column chromatography. Here we describe the generation of a recombinant expression system to produce purified human eIF2 from yeast cells. We demonstrate that human eIF2 can function in yeast cells in place of the equivalent yeast factor. We purify human eIF2 and the C-terminal domain of human eIF2Bε using affinity chromatography from engineered yeast cells and find that both function in a GEF assay: the first demonstration that this human eIF2Bε domain has GEF function. We show that CACH/VWM mutations within this domain reduce its activity. Finally we demonstrate that the recombinant eIF2 functions similarly to eIF2 purified from rat liver in GEF assays with CACH/VWM eIF2B-mutated patient derived lymphocytic cells.
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The yeast eukaryotic translation initiation factor 2B translation initiation complex interacts with the fatty acid synthesis enzyme YBR159W and endoplasmic reticulum membranes. Mol Cell Biol 2012; 33:1041-56. [PMID: 23263984 DOI: 10.1128/mcb.00811-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Using affinity purifications coupled with mass spectrometry and yeast two-hybrid assays, we show the Saccharomyces cerevisiae translation initiation factor complex eukaryotic translation initiation factor 2B (eIF2B) and the very-long-chain fatty acid (VLCFA) synthesis keto-reductase enzyme YBR159W physically interact. The data show that the interaction is specifically between YBR159W and eIF2B and not between other members of the translation initiation or VLCFA pathways. A ybr159wΔ null strain has a slow-growth phenotype and a reduced translation rate but a normal GCN4 response to amino acid starvation. Although YBR159W localizes to the endoplasmic reticulum membrane, subcellular fractionation experiments show that a fraction of eIF2B cofractionates with lipid membranes in a YBR159W-independent manner. We show that a ybr159wΔ yeast strain and other strains with null mutations in the VLCFA pathway cause eIF2B to appear as numerous foci throughout the cytoplasm.
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