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Shimasaki K, Okemoto-Nakamura Y, Saito K, Fukasawa M, Katoh K, Hanada K. A high-resolution phase-contrast microscopy system for label-free imaging in living cells. Cell Struct Funct 2024; 49:21-29. [PMID: 38797697 DOI: 10.1247/csf.24018] [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] [Indexed: 05/29/2024] Open
Abstract
Cell biologists have long sought the ability to observe intracellular structures in living cells without labels. This study presents procedures to adjust a commercially available apodized phase-contrast (APC) microscopy system for better visualizing the dynamic behaviors of various subcellular organelles in living cells. By harnessing the versatility of this technique to capture sequential images, we could observe morphological changes in cellular geometry after virus infection in real time without probes or invasive staining. The tune-up APC microscopy system is a highly efficient platform for simultaneously observing the dynamic behaviors of diverse subcellular structures with exceptional resolution.
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Affiliation(s)
- Kentaro Shimasaki
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases
| | - Yuko Okemoto-Nakamura
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases
| | - Kyoko Saito
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases
| | - Masayoshi Fukasawa
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
- AIRC, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Kentaro Hanada
- Center for Quality Management Systems, National Institute of Infectious Diseases
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2
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Sarkar R, Chhabra S, Tanwar M, Agarwal N, Kalia M. Japanese encephalitis virus hijacks ER-associated degradation regulators for its replication. J Gen Virol 2024; 105. [PMID: 38787366 DOI: 10.1099/jgv.0.001995] [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] [Indexed: 05/25/2024] Open
Abstract
Flaviviruses target their replication on membranous structures derived from the ER, where both viral and host proteins play crucial structural and functional roles. Here, we have characterized the involvement of the ER-associated degradation (ERAD) pathway core E3 ligase complex (SEL1L-HRD1) regulator proteins in the replication of Japanese encephalitis virus (JEV). Through high-resolution immunofluorescence imaging of JEV-infected HeLa cells, we observe that the virus replication complexes marked by NS1 strongly colocalize with the ERAD adapter SEL1L, lectin OS9, ER-membrane shuttle factor HERPUD1, E3 ubiquitin ligase HRD1 and rhomboid superfamily member DERLIN1. NS5 positive structures also show strong overlap with SEL1L. While these effectors show significant transcriptional upregulation, their protein levels remain largely stable in infected cells. siRNA mediated depletion of OS9, SEL1L, HERPUD1 and HRD1 significantly inhibit viral RNA replication and titres, with SEL1L depletion showing the maximum attenuation of replication. By performing protein translation arrest experiments, we show that SEL1L, and OS9 are stabilised upon JEV infection. Overall results from this study suggest that these ERAD effector proteins are crucial host-factors for JEV replication.
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Affiliation(s)
- Riya Sarkar
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
- Centre for Tuberculosis Research, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
- Present address: Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Simran Chhabra
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Mukesh Tanwar
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Nisheeth Agarwal
- Centre for Tuberculosis Research, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Manjula Kalia
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
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3
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Wu L, Zhang L, Feng S, Chen L, Lin C, Wang G, Zhu Y, Wang P, Cheng G. An evolutionarily conserved ubiquitin ligase drives infection and transmission of flaviviruses. Proc Natl Acad Sci U S A 2024; 121:e2317978121. [PMID: 38593069 PMCID: PMC11032495 DOI: 10.1073/pnas.2317978121] [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: 10/17/2023] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
Mosquito-borne flaviviruses such as dengue (DENV) and Zika (ZIKV) cause hundreds of millions of infections annually. The single-stranded RNA genome of flaviviruses is translated into a polyprotein, which is cleaved equally into individual functional proteins. While structural proteins are packaged into progeny virions and released, most of the nonstructural proteins remain intracellular and could become cytotoxic if accumulated over time. However, the mechanism by which nonstructural proteins are maintained at the levels optimal for cellular fitness and viral replication remains unknown. Here, we identified that the ubiquitin E3 ligase HRD1 is essential for flaviviruses infections in both mammalian hosts and mosquitoes. HRD1 directly interacts with flavivirus NS4A and ubiquitylates a conserved lysine residue for ER-associated degradation. This mechanism avoids excessive accumulation of NS4A, which otherwise interrupts the expression of processed flavivirus proteins in the ER. Furthermore, a small-molecule inhibitor of HRD1 named LS-102 effectively interrupts DENV2 infection in both mice and Aedes aegypti mosquitoes, and significantly disturbs DENV transmission from the infected hosts to mosquitoes owing to reduced viremia. Taken together, this study demonstrates that flaviviruses have evolved a sophisticated mechanism to exploit the ubiquitination system to balance the homeostasis of viral proteins for their own advantage and provides a potential therapeutic target to interrupt flavivirus infection and transmission.
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Affiliation(s)
- Linjuan Wu
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen518000, China
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen518055, China
| | - Liming Zhang
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
| | - Shengyong Feng
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen518000, China
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen518055, China
| | - Lu Chen
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
| | - Cai Lin
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen518000, China
| | - Gang Wang
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
| | - Yibin Zhu
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen518055, China
| | - Penghua Wang
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT06030
| | - Gong Cheng
- New Cornerstone Science Laboratory, Tsinghua University-Peking University Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing100084, China
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen518000, China
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen518055, China
- Southwest United Graduate School, Kunming650092, China
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4
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Cao H, Zhou X, Xu B, Hu H, Guo J, Ma Y, Wang M, Li N, Jun Z. Advances in the study of protein folding and endoplasmic reticulum-associated degradation in mammal cells. J Zhejiang Univ Sci B 2024; 25:212-232. [PMID: 38453636 PMCID: PMC10918413 DOI: 10.1631/jzus.b2300403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 08/03/2023] [Indexed: 03/09/2024]
Abstract
The endoplasmic reticulum is a key site for protein production and quality control. More than one-third of proteins are synthesized and folded into the correct three-dimensional conformation in the endoplasmic reticulum. However, during protein folding, unfolded and/or misfolded proteins are prone to occur, which may lead to endoplasmic reticulum stress. Organisms can monitor the quality of the proteins produced by endoplasmic reticulum quality control (ERQC) and endoplasmic reticulum-associated degradation (ERAD), which maintain endoplasmic reticulum protein homeostasis by degrading abnormally folded proteins. The underlying mechanisms of protein folding and ERAD in mammals have not yet been fully explored. Therefore, this paper reviews the process and function of protein folding and ERAD in mammalian cells, in order to help clinicians better understand the mechanism of ERAD and to provide a scientific reference for the treatment of diseases caused by abnormal ERAD.
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Affiliation(s)
- Hong Cao
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China
- National Key Laboratory of Immunity and Inflammation, Naval Medical University, Shanghai 200433, China
| | - Xuchang Zhou
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China
| | - Bowen Xu
- National Key Laboratory of Immunity and Inflammation, Naval Medical University, Shanghai 200433, China
| | - Han Hu
- National Key Laboratory of Immunity and Inflammation, Naval Medical University, Shanghai 200433, China
| | - Jianming Guo
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China
| | - Yuwei Ma
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China
| | - Miao Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China
| | - Nan Li
- National Key Laboratory of Immunity and Inflammation, Naval Medical University, Shanghai 200433, China.
| | - Zou Jun
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai 200438, China.
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Christianson JC, Jarosch E, Sommer T. Mechanisms of substrate processing during ER-associated protein degradation. Nat Rev Mol Cell Biol 2023; 24:777-796. [PMID: 37528230 DOI: 10.1038/s41580-023-00633-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2023] [Indexed: 08/03/2023]
Abstract
Maintaining proteome integrity is essential for long-term viability of all organisms and is overseen by intrinsic quality control mechanisms. The secretory pathway of eukaryotes poses a challenge for such quality assurance as proteins destined for secretion enter the endoplasmic reticulum (ER) and become spatially segregated from the cytosolic machinery responsible for disposal of aberrant (misfolded or otherwise damaged) or superfluous polypeptides. The elegant solution provided by evolution is ER-membrane-bound ubiquitylation machinery that recognizes misfolded or surplus proteins or by-products of protein biosynthesis in the ER and delivers them to 26S proteasomes for degradation. ER-associated protein degradation (ERAD) collectively describes this specialized arm of protein quality control via the ubiquitin-proteasome system. But, instead of providing a single strategy to remove defective or unwanted proteins, ERAD represents a collection of independent processes that exhibit distinct yet overlapping selectivity for a wide range of substrates. Not surprisingly, ER-membrane-embedded ubiquitin ligases (ER-E3s) act as central hubs for each of these separate ERAD disposal routes. In these processes, ER-E3s cooperate with a plethora of specialized factors, coordinating recognition, transport and ubiquitylation of undesirable secretory, membrane and cytoplasmic proteins. In this Review, we focus on substrate processing during ERAD, highlighting common threads as well as differences between the many routes via ERAD.
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Affiliation(s)
- John C Christianson
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
| | - Ernst Jarosch
- Max-Delbrück-Centrer for Molecular Medicine in Helmholtz Association, Berlin-Buch, Germany
| | - Thomas Sommer
- Max-Delbrück-Centrer for Molecular Medicine in Helmholtz Association, Berlin-Buch, Germany.
- Institute for Biology, Humboldt Universität zu Berlin, Berlin, Germany.
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Ishida K, Yagi H, Kato Y, Morita E. N-linked glycosylation of flavivirus E protein contributes to viral particle formation. PLoS Pathog 2023; 19:e1011681. [PMID: 37819933 PMCID: PMC10593244 DOI: 10.1371/journal.ppat.1011681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/23/2023] [Accepted: 09/12/2023] [Indexed: 10/13/2023] Open
Abstract
In the case of the Japanese encephalitis virus (JEV), the envelope protein (E), a major component of viral particles, contains a highly conserved N-linked glycosylation site (E: N154). Glycosylation of the E protein is thought to play an important role in the ability of the virus to attach to target cells during transmission; however, its role in viral particle formation and release remains poorly understood. In this study, we investigated the role of N-glycosylation of flaviviral structural proteins in viral particle formation and secretion by introducing mutations in viral structural proteins or cellular factors involved in glycoprotein transport and processing. The number of secreted subviral particles (SVPs) was significantly reduced in N154A, a glycosylation-null mutant, but increased in D67N, a mutant containing additional glycosylation sites, indicating that the amount of E glycosylation regulates the release of SVPs. SVP secretion was reduced in cells deficient in galactose, sialic acid, and N-acetylglucosamine modifications in the Golgi apparatus; however, these reductions were not significant, suggesting that glycosylation mainly plays a role in pre-Golgi transport. Fluorescent labeling of SVPs using a split green fluorescent protein (GFP) system and time-lapse imaging by retention using selective hooks (RUSH) system revealed that the glycosylation-deficient mutant was arrested before endoplasmic reticulum (ER)- Golgi transport. However, the absence of ERGIC-53 and ERGIC-L, ER-Golgi transport cargo receptors that recognize sugar chains on cargo proteins, does not impair SVP secretion. In contrast, the solubility of the N154A mutant of E or the N15A/T17A mutant of prM in cells was markedly lower than that of the wild type, and proteasome-mediated rapid degradation of these mutants was observed, indicating the significance of glycosylation of both prM and E in proper protein folding and assembly of viral particles in the ER.
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Affiliation(s)
- Kotaro Ishida
- Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Japan
- Division of Biomolecular Function, Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Japan
| | - Yukinari Kato
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Eiji Morita
- Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Japan
- Division of Biomolecular Function, Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
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Abstract
Understanding the factors that shape viral evolution is critical for developing effective antiviral strategies, accurately predicting viral evolution, and preventing pandemics. One fundamental determinant of viral evolution is the interplay between viral protein biophysics and the host machineries that regulate protein folding and quality control. Most adaptive mutations in viruses are biophysically deleterious, resulting in a viral protein product with folding defects. In cells, protein folding is assisted by a dynamic system of chaperones and quality control processes known as the proteostasis network. Host proteostasis networks can determine the fates of viral proteins with biophysical defects, either by assisting with folding or by targeting them for degradation. In this review, we discuss and analyze new discoveries revealing that host proteostasis factors can profoundly shape the sequence space accessible to evolving viral proteins. We also discuss the many opportunities for research progress proffered by the proteostasis perspective on viral evolution and adaptation.
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Affiliation(s)
- Jimin Yoon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
| | - Jessica E Patrick
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
| | - C Brandon Ogbunugafor
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Matthew D Shoulders
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
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Das B, Samal S, Hamdi H, Pal A, Biswas A, Behera J, Singh G, Behera CK, Sahoo DP, Pati S. Role of endoplasmic reticulum stress-related unfolded protein response and its implications in dengue virus infection for biomarker development. Life Sci 2023; 329:121982. [PMID: 37517582 DOI: 10.1016/j.lfs.2023.121982] [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: 04/29/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Dengue virus (DENV) causes debilitating disease in humans, which varies at different rates in host cells, such as monocytes, macrophages, dendritic cells, Langerhans cells, and other cell types. Such heterogeneity in DENV infection in cells could be attributed to a range of factors, including host cell immune response, anti-viral cellular proteins, and virus mediated cellular autophagy. This review delineates an important feature of every cell, the unfolded protein response (UPR) that is attributed to the accumulation of several viral and unfolded/misfolded proteins, such as in DENV infection. UPR is a normal process to counteract endoplasmic reticulum (ER) stress that leads to cell autophagy; though the phenomenon is markedly upregulated during DENV infection. This could be attributed to the uncontrolled activation of the key UPR signaling pathways: inositol-requiring transmembrane kinase/endoribonuclease 1 (IRE1), protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), and activating transcription factor-6 (ATF6), which promote cell autophagy under normal and diseased conditions through the downstream regulation of apoptosis promoting factors such as X-box binding protein (XBP1), GADD34, and ATF-6. Because DENV can modulate these signaling cascades, by promoting dysregulated cell autophagy, the ER stress mediated UPR pathways and the inherent agents could play an important role in delineating the severity of dengue infection with a potential for developing DENV targeted therapeutics.
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Affiliation(s)
- Biswadeep Das
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India.
| | - Sagnika Samal
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India
| | - Hamida Hamdi
- Zoology Department, Faculty of Science, Cairo University, Giza 12613, Egypt; Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Aditi Pal
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India
| | - Arpita Biswas
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India
| | - Jyotika Behera
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India
| | - Gyanraj Singh
- Department of Anatomy, Kalinga Institute of Medical Sciences, KIIT-DU, Bhubaneswar, Odisha 751024, India
| | - Chinmay Kumar Behera
- Department of Pediatrics, Kalinga Institute of Medical Sciences, KIIT-DU, Bhubaneswar, Odisha 751024, India
| | - Debee Prasad Sahoo
- School of Biotechnology, Kalinga Institute of Industrial Technology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024, India
| | - Sanghamitra Pati
- Regional Medical Research Centre-ICMR, Nalco Square, Bhubaneswar, Odisha 751023, India
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Chu S, Xie X, Payan C, Stochaj U. Valosin containing protein (VCP): initiator, modifier, and potential drug target for neurodegenerative diseases. Mol Neurodegener 2023; 18:52. [PMID: 37545006 PMCID: PMC10405438 DOI: 10.1186/s13024-023-00639-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023] Open
Abstract
The AAA+ ATPase valosin containing protein (VCP) is essential for cell and organ homeostasis, especially in cells of the nervous system. As part of a large network, VCP collaborates with many cofactors to ensure proteostasis under normal, stress, and disease conditions. A large number of mutations have revealed the importance of VCP for human health. In particular, VCP facilitates the dismantling of protein aggregates and the removal of dysfunctional organelles. These are critical events to prevent malfunction of the brain and other parts of the nervous system. In line with this idea, VCP mutants are linked to the onset and progression of neurodegeneration and other diseases. The intricate molecular mechanisms that connect VCP mutations to distinct brain pathologies continue to be uncovered. Emerging evidence supports the model that VCP controls cellular functions on multiple levels and in a cell type specific fashion. Accordingly, VCP mutants derail cellular homeostasis through several mechanisms that can instigate disease. Our review focuses on the association between VCP malfunction and neurodegeneration. We discuss the latest insights in the field, emphasize open questions, and speculate on the potential of VCP as a drug target for some of the most devastating forms of neurodegeneration.
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Affiliation(s)
- Siwei Chu
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Xinyi Xie
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Carla Payan
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Ursula Stochaj
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada.
- Quantitative Life Sciences Program, McGill University, Montreal, Canada.
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Wang W, Bi Z, Liu Y, Xia X, Qian J, Tan Y, Zhao J, Song S. The H protein of attenuated canine distemper virus is degraded via endoplasmic reticulum-associated protein degradation. Front Vet Sci 2023; 10:1214318. [PMID: 37483299 PMCID: PMC10359071 DOI: 10.3389/fvets.2023.1214318] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/16/2023] [Indexed: 07/25/2023] Open
Abstract
Canine distemper (CD) caused by canine distemper virus (CDV) is considered a highly contagious and acutely febrile disease in various animals around the world. Endoplasmic reticulum-associated protein degradation (ERAD) is an important biological effect induced by endoplasmic reticulum (ER) stress (ERS) for the degradation of unfolded/misfolded proteins in the ER of cells. CDV H glycoprotein is translocated into the ER for post-translational modifications. The effects of CDV H and ER on each other are unclear. In this study, we found that CDV H protein induced ERS through the PERK-mediated signaling pathway. The inhibition of ERS by 4-Phenylbutyric acid (4-PBA) increased the H protein amounts of an attenuated CDV, which was reduced by dithiothreitol (DTT)-induced ERS. Further, the H protein levels were increased when ERAD was inhibited by using Eeyarestatin I or interfering E3 ligase Hrd1 in ERAD, suggesting that the attenuated CDV H protein is degraded via ERAD. ERAD involved ubiquitin-dependent proteasome degradation (UPD) and/or autophagic-lysosome degradation (ALD). The attenuated CDV H protein was ubiquitinated and significantly increased after treatment with UPD inhibitor MG132 but not ALD inhibitor chloroquine (CQ), suggesting that ERAD degrading the attenuated CDV H protein selectively depends on UPD. Moreover, the inhibition of the degradation of CDV H protein with 4-PBA or MG132 treatment increased viral replication, whereas treatment with DTT promoting degradation of H protein was found to reduce viral replication. These findings suggest that the degradation of CDV H protein via ERAD negatively affects viral replication and provide a new idea for developing CDV prevention and control strategies.
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Affiliation(s)
- Wenjie Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, Jiangsu, China
| | - Zhenwei Bi
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, Jiangsu, China
| | - Yakun Liu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang, China
| | - Xingxia Xia
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, Jiangsu, China
| | - Jing Qian
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, Jiangsu, China
| | - Yeping Tan
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, Jiangsu, China
| | - Jianjun Zhao
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang, China
| | - Suquan Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
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11
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Wang W, Bi Z, Song S. Host E3 ligase Hrd1 ubiquitinates and degrades H protein of canine distemper virus to inhibit viral replication. Vet Res 2023; 54:30. [PMID: 37009870 PMCID: PMC10069049 DOI: 10.1186/s13567-023-01163-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/01/2023] [Indexed: 04/04/2023] Open
Abstract
Canine distemper (CD) is a highly contagious and an acutely febrile disease caused by canine distemper virus (CDV), which greatly threatens the dog and fur industry in many countries. Endoplasmic reticulum (ER)-associated degradation (ERAD) is a protein quality control system for the degradation of misfolded proteins in the ER. In this study, a proteomic approach was performed, and results found the E3 ubiquitin ligase 3-hydroxy-3-methylglutaryl reductase degradation protein 1 (Hrd1), which is involved in ERAD, as one of the CDV H-interacting proteins. The interaction of Hrd1 with CDV H protein was further identified by Co-IP assay and confocal microscopy. Hrd1 degraded the CDV H protein via the proteasome pathway dependent on its E3 ubiquitin ligase activity. Hrd1 catalyzed the K63-linked polyubiquitination of CDV H protein at lysine residue 115 (K115). Hrd1 also exhibited a significant inhibitory effect on CDV replication. Together, the data demonstrate that the E3 ligase Hrd1 mediates the ubiquitination of CDV H protein for degradation via the proteasome pathway and inhibits CDV replication. Thus, targeting Hrd1 may represent a novel prevention and control strategy for CDV infection.
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Affiliation(s)
- Wenjie Wang
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, 210014, Jiangsu, China
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Zhenwei Bi
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-Products, Nanjing, 210014, Jiangsu, China.
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
- GuoTai (Taizhou) Center of Technology Innovation for Veterinary Biologicals, Taizhou, 225300, Jiangsu, China.
| | - Suquan Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
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Bhaduri S, Scott NA, Neal SE. The Role of the Rhomboid Superfamily in ER Protein Quality Control: From Mechanisms and Functions to Diseases. Cold Spring Harb Perspect Biol 2023; 15:a041248. [PMID: 35940905 PMCID: PMC9899648 DOI: 10.1101/cshperspect.a041248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The endoplasmic reticulum (ER) is an essential organelle in eukaryotic cells and is a major site for protein folding, modification, and lipid synthesis. Perturbations within the ER, such as protein misfolding and high demand for protein folding, lead to dysregulation of the ER protein quality control network and ER stress. Recently, the rhomboid superfamily has emerged as a critical player in ER protein quality control because it has diverse cellular functions, including ER-associated degradation (ERAD), endosome Golgi-associated degradation (EGAD), and ER preemptive quality control (ERpQC). This breadth of function both illustrates the importance of the rhomboid superfamily in health and diseases and emphasizes the necessity of understanding their mechanisms of action. Because dysregulation of rhomboid proteins has been implicated in various diseases, such as neurological disorders and cancers, they represent promising potential therapeutic drug targets. This review provides a comprehensive account of the various roles of rhomboid proteins in the context of ER protein quality control and discusses their significance in health and disease.
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Affiliation(s)
- Satarupa Bhaduri
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
| | - Nicola A Scott
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
| | - Sonya E Neal
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
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Sharma KB, Chhabra S, Kalia M. Japanese Encephalitis Virus-Infected Cells. Subcell Biochem 2023; 106:251-281. [PMID: 38159231 DOI: 10.1007/978-3-031-40086-5_10] [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] [Indexed: 01/03/2024]
Abstract
RNA virus infections have been a leading cause of pandemics. Aided by global warming and increased connectivity, their threat is likely to increase over time. The flaviviruses are one such RNA virus family, and its prototypes such as the Japanese encephalitis virus (JEV), Dengue virus, Zika virus, West Nile virus, etc., pose a significant health burden on several endemic countries. All viruses start off their life cycle with an infected cell, wherein a series of events are set in motion as the virus and host battle for autonomy. With their remarkable capacity to hijack cellular systems and, subvert/escape defence pathways, viruses are able to establish infection and disseminate in the body, causing disease. Using this strategy, JEV replicates and spreads through several cell types such as epithelial cells, fibroblasts, monocytes and macrophages, and ultimately breaches the blood-brain barrier to infect neurons and microglia. The neurotropic nature of JEV, its high burden on the paediatric population, and its lack of any specific antivirals/treatment strategies emphasise the need for biomedical research-driven solutions. Here, we highlight the latest research developments on Japanese encephalitis virus-infected cells and discuss how these can aid in the development of future therapies.
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Affiliation(s)
- Kiran Bala Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Simran Chhabra
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Manjula Kalia
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India.
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Ci Y, Yao B, Yue K, Yang Y, Xu C, Li DF, Qin CF, Shi L. Bortezomib inhibits ZIKV/DENV by interfering with viral polyprotein cleavage via the ERAD pathway. Cell Chem Biol 2022; 30:527-539.e5. [DOI: 10.1016/j.chembiol.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 09/08/2022] [Accepted: 09/30/2022] [Indexed: 11/09/2022]
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Rodrigo I, Ballesta C, Nunes EB, Pérez P, García-Arriaza J, Arias A. Eeyarestatin I, an inhibitor of the valosin-containing protein, exhibits potent virucidal activity against the flaviviruses. Antiviral Res 2022; 207:105416. [PMID: 36113629 DOI: 10.1016/j.antiviral.2022.105416] [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: 06/18/2022] [Revised: 09/05/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022]
Abstract
Cellular responses to stress generally lead to the activation of the endoplasmic reticulum-associated protein degradation (ERAD) pathway. Several lines of study support that ERAD may be playing a proviral role during flaviviral infection. A key host factor in ERAD is the valosin-containing protein (VCP), an ATPase which ushers ubiquitin-tagged proteins to degradation by the proteasome. VCP exhibits different proviral activities, such as engaging in the biogenesis of viral replication organelles and facilitating flavivirus genome uncoating after the viral particle entry. To investigate the possible antiviral value of drugs targeting VCP, we tested two inhibitors: eeyarestatin I (EEY) and xanthohumol (XAN). Both compounds were highly effective in suppressing Zika virus (ZIKV) and Usutu virus (USUV) replication during infection in cell culture. Further analysis revealed an unexpected virucidal activity for EEY, but not for XAN. Preincubation of ZIKV or USUV with EEY before inoculation to cells resulted in significant decreases in infectivity in a dose- and time-dependent manner. Viral genomes in samples previously treated with EEY were more sensitive to propidium monoazide, an intercalating agent, with 10- to 100-fold decreases observed in viral RNA levels, supporting that EEY affects viral particle integrity. Altogether, these results support that EEY is a strong virucide against two unrelated flaviviruses, encouraging further studies to investigate its potential use as a broad-acting drug or the development of improved derivatives in the treatment of flaviviral infection.
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Affiliation(s)
- Imanol Rodrigo
- Unidad de Medicina Molecular, Centro Regional de Investigaciones Biomedicas (CRIB), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain; Unidad de Biomedicina, UCLM-CSIC, Albacete, Spain
| | - Carlos Ballesta
- Unidad de Medicina Molecular, Centro Regional de Investigaciones Biomedicas (CRIB), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain; Unidad de Biomedicina, UCLM-CSIC, Albacete, Spain
| | - Eliane Blanco Nunes
- Departamento de Vigilância em Zoonoses, Secretaria Municipal de Saúde Goiânia, Rodovia Go-020 km 08, Val Das Pombas, 75250-000, Goiânia, Goias State, Brazil
| | - Patricia Pérez
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnologla (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain; Centro de Investigacion Biomedica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Juan García-Arriaza
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnologla (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain; Centro de Investigacion Biomedica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Armando Arias
- Unidad de Medicina Molecular, Centro Regional de Investigaciones Biomedicas (CRIB), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain; Unidad de Biomedicina, UCLM-CSIC, Albacete, Spain; Escuela Técnica Superior de Ingenieros Agrónomos, UCLM, Albacete, Spain.
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Viruses Hijack ERAD to Regulate Their Replication and Propagation. Int J Mol Sci 2022; 23:ijms23169398. [PMID: 36012666 PMCID: PMC9408921 DOI: 10.3390/ijms23169398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/25/2022] Open
Abstract
Endoplasmic reticulum-associated degradation (ERAD) is highly conserved in yeast. Recent studies have shown that ERAD is also ubiquitous and highly conserved in eukaryotic cells, where it plays an essential role in maintaining endoplasmic reticulum (ER) homeostasis. Misfolded or unfolded proteins undergo ERAD. They are recognized in the ER, retrotranslocated into the cytoplasm, and degraded by proteasomes after polyubiquitin. This may consist of several main steps: recognition of ERAD substrates, retrotranslocation, and proteasome degradation. Replication and transmission of the virus in the host is a process of a “game” with the host. It can be assumed that the virus has evolved various mechanisms to use the host’s functions for its replication and transmission, including ERAD. However, until now, it is still unclear how the host uses ERAD to deal with virus infection and how the viruses hijack the function of ERAD to obtain a favorable niche or evade the immune clearance of the host. Recent studies have shown that viruses have also evolved mechanisms to use various processes of ERAD to promote their transmission. This review describes the occurrence of ERAD and how the viruses hijack the function of ERAD to spread by affecting the homeostasis and immune response of the host, and we will focus on the role of E3 ubiquitin ligase.
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Li Q, Kang C. Dengue virus NS4B protein as a target for developing antivirals. Front Cell Infect Microbiol 2022; 12:959727. [PMID: 36017362 PMCID: PMC9398000 DOI: 10.3389/fcimb.2022.959727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/21/2022] [Indexed: 12/04/2022] Open
Abstract
Dengue virus is an important pathogen affecting global population while no specific treatment is available against this virus. Effort has been made to develop inhibitors through targeting viral nonstructural proteins such as NS3 and NS5 with enzymatic activities. No potent inhibitors entering clinical studies have been developed so far due to many challenges. The genome of dengue virus encodes four membrane-bound nonstructural proteins which do not possess any enzymatic activities. Studies have shown that the membrane protein-NS4B is a validated target for drug discovery and several NS4B inhibitors exhibited antiviral activities in various assays and entered preclinical studies.. Here, we summarize the recent studies on dengue NS4B protein. The structure and membrane topology of dengue NS4B derived from biochemical and biophysical studies are described. Function of NS4B through protein-protein interactions and some available NS4B inhibitors are summarized. Accumulated studies demonstrated that cell-based assays play important roles in developing NS4B inhibitors. Although the atomic structure of NS4B is not obtained, target-based drug discovery approach become feasible to develop NS4B inhibitors as recombinant NS4B protein is available.
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Affiliation(s)
- Qingxin Li
- Guangdong Provincial Engineering Laboratory of Biomass High Value Utilization, Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou, China
- *Correspondence: Qingxin Li, ; Congbao Kang,
| | - Congbao Kang
- Experimental Drug Development Centre, Agency for Science, Technology and Research, Singapore, Singapore
- *Correspondence: Qingxin Li, ; Congbao Kang,
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Neufeldt CJ, Cortese M. Membrane architects: how positive-strand RNA viruses restructure the cell. J Gen Virol 2022; 103. [PMID: 35976091 DOI: 10.1099/jgv.0.001773] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Virus infection is a process that requires combined contributions from both virus and host factors. For this process to be efficient within the crowded host environment, viruses have evolved ways to manipulate and reorganize host structures to produce cellular microenvironments. Positive-strand RNA virus replication and assembly occurs in association with cytoplasmic membranes, causing a reorganization of these membranes to create microenvironments that support viral processes. Similarities between virus-induced membrane domains and cellular organelles have led to the description of these structures as virus replication organelles (vRO). Electron microscopy analysis of vROs in positive-strand RNA virus infected cells has revealed surprising morphological similarities between genetically diverse virus species. For all positive-strand RNA viruses, vROs can be categorized into two groups: those that make invaginations into the cellular membranes (In-vRO), and those that cause the production of protrusions from cellular membranes (Pr-vRO), most often in the form of double membrane vesicles (DMVs). In this review, we will discuss the current knowledge on the structure and biogenesis of these two different vRO classes as well as comparing morphology and function of vROs between various positive-strand RNA viruses. Finally, we will discuss recent studies describing pharmaceutical intervention in vRO formation as an avenue to control virus infection.
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Affiliation(s)
- Christopher John Neufeldt
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Mirko Cortese
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
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Flavivirus recruits the valosin-containing protein-NPL4 complex to induce stress granule disassembly for efficient viral genome replication. J Biol Chem 2022; 298:101597. [PMID: 35063505 PMCID: PMC8857493 DOI: 10.1016/j.jbc.2022.101597] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 11/23/2022] Open
Abstract
Flaviviruses are human pathogens that can cause severe diseases, such as dengue fever and Japanese encephalitis, which can lead to death. Valosin-containing protein (VCP)/p97, a cellular ATPase associated with diverse cellular activities (AAA-ATPase), is reported to have multiple roles in flavivirus replication. Nevertheless, the importance of each role still has not been addressed. In this study, the functions of 17 VCP mutants that are reportedly unable to interact with the VCP cofactors were validated using the short-interfering RNA rescue experiments. Our findings of this study suggested that VCP exerts its functions in replication of the Japanese encephalitis virus by interacting with the VCP cofactor nuclear protein localization 4 (NPL4). We show that the depletion of NPL4 impaired the early stage of viral genome replication. In addition, we demonstrate that the direct interaction between NPL4 and viral nonstructural protein (NS4B) is critical for the translocation of NS4B to the sites of viral replication. Finally, we found that Japanese encephalitis virus and dengue virus promoted stress granule formation only in VCP inhibitor-treated cells and the expression of NS4B or VCP attenuated stress granule formation mediated by protein kinase R, which is generally known to be activated by type I interferon and viral genome RNA. These results suggest that the NS4B-mediated recruitment of VCP to the virus replication site inhibits cellular stress responses and consequently facilitates viral protein synthesis in the flavivirus-infected cells.
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The Biogenesis of Dengue Virus Replication Organelles Requires the ATPase Activity of Valosin-Containing Protein. Viruses 2021; 13:v13102092. [PMID: 34696522 PMCID: PMC8540793 DOI: 10.3390/v13102092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/13/2021] [Indexed: 12/03/2022] Open
Abstract
The dengue virus (DENV) causes the most prevalent arthropod-borne viral disease worldwide. While its incidence is increasing in many countries, there is no approved antiviral therapy currently available. In infected cells, the DENV induces extensive morphological alterations of the endoplasmic reticulum (ER) to generate viral replication organelles (vRO), which include convoluted membranes (CM) and vesicle packets (VP) hosting viral RNA replication. The viral non-structural protein NS4B localizes to vROs and is absolutely required for viral replication through poorly defined mechanisms, which might involve cellular protein partners. Previous interactomic studies identified the ATPase valosin-containing protein (VCP) as a DENV NS4B-interacting host factor in infected cells. Using both pharmacological and dominant-negative inhibition approaches, we show, in this study, that VCP ATPase activity is required for efficient DENV replication. VCP associates with NS4B when expressed in the absence of other viral proteins while in infected cells, both proteins colocalize within large DENV-induced cytoplasmic structures previously demonstrated to be CMs. Consistently, VCP inhibition dramatically reduces the abundance of DENV CMs in infected cells. Most importantly, using a recently reported replication-independent plasmid-based vRO induction system, we show that de novo VP biogenesis is dependent on VCP ATPase activity. Overall, our data demonstrate that VCP ATPase activity is required for vRO morphogenesis and/or stability. Considering that VCP was shown to be required for the replication of other flaviviruses, our results argue that VCP is a pan-flaviviral host dependency factor. Given that new generation VCP-targeting drugs are currently evaluated in clinical trials for cancer treatment, VCP may constitute an attractive broad-spectrum antiviral target in drug repurposing approaches.
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