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Bodmer BS, Hoenen T, Wendt L. Molecular insights into the Ebola virus life cycle. Nat Microbiol 2024; 9:1417-1426. [PMID: 38783022 DOI: 10.1038/s41564-024-01703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Ebola virus and other orthoebolaviruses cause severe haemorrhagic fevers in humans, with very high case fatality rates. Their non-segmented single-stranded RNA genome encodes only seven structural proteins and a small number of non-structural proteins to facilitate the virus life cycle. The basics of this life cycle are well established, but recent advances have substantially increased our understanding of its molecular details, including the viral and host factors involved. Here we provide a comprehensive overview of our current knowledge of the molecular details of the orthoebolavirus life cycle, with a special focus on proviral host factors. We discuss the multistep entry process, viral RNA synthesis in specialized phase-separated intracellular compartments called inclusion bodies, the expression of viral proteins and ultimately the assembly of new virus particles and their release at the cell surface. In doing so, we integrate recent studies into the increasingly detailed model that has developed for these fundamental aspects of orthoebolavirus biology.
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Affiliation(s)
- Bianca S Bodmer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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2
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Spada SJ, Rose KM, Sette P, O'Connor SK, Dussupt V, Siddartha Yerramilli V, Nagashima K, Sjoelund VH, Cruz P, Kabat J, Ganesan S, Smelkinson M, Nita-Lazar A, Hoyt F, Scarlata S, Hirsch V, Best SM, Grigg ME, Bouamr F. Human ESCRT-I and ALIX function as scaffolding helical filaments in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592080. [PMID: 38903125 PMCID: PMC11188096 DOI: 10.1101/2024.05.01.592080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
The Endosomal Sorting Complex Required for Transport (ESCRT) is an evolutionarily conserved machinery that performs reverse-topology membrane scission in cells universally required from cytokinesis to budding of enveloped viruses. Upstream acting ESCRT-I and ALIX control these events and link recruitment of viral and cellular partners to late-acting ESCRT-III CHMP4 through incompletely understood mechanisms. Using structure-function analyses combined with super-resolution imaging, we show that ESCRT-I and ALIX function as distinct helical filaments in vivo . Together, they are essential for optimal structural scaffolding of HIV-1 nascent virions, the retention of viral and human genomes through defined functional interfaces, and recruitment of CHMP4 that itself assembles into corkscrew-like filaments intertwined with ESCRT-I or ALIX helices. Disruption of filament assembly or their conformationally clustered RNA binding interfaces in human cells impaired membrane abscission, resulted in major structural instability and leaked nucleic acid from nascent virions and nuclear envelopes. Thus, ESCRT-I and ALIX function as helical filaments in vivo and serve as both nucleic acid-dependent structural scaffolds as well as ESCRT-III assembly templates. Significance statement When cellular membranes are dissolved or breached, ESCRT is rapidly deployed to repair membranes to restore the integrity of intracellular compartments. Membrane sealing is ensured by ESCRT-III filaments assembled on the inner face of membrane; a mechanism termed inverse topology membrane scission. This mechanism, initiated by ESCRT-I and ALIX, is universally necessary for cytokinesis, wound repair, budding of enveloped viruses, and more. We show ESCRT-I and ALIX individually oligomerize into helical filaments that cluster newly discovered nucleic acid-binding interfaces and scaffold-in genomes within nascent virions and nuclear envelopes. These oligomers additionally appear to serve as ideal templates for ESCRT-III polymerization, as helical filaments of CHMP4B were found intertwined ESCRT-I or ALIX filaments in vivo . Similarly, corkscrew-like filaments of ALIX are also interwoven with ESCRT-I, supporting a model of inverse topology membrane scission that is synergistically reinforced by inward double filament scaffolding.
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Johnson KA, Budicini MR, Bhattarai N, Sharma T, Urata S, Gerstman BS, Chapagain PP, Li S, Stahelin RV. PI(4,5)P 2 binding sites in the Ebola virus matrix protein VP40 modulate assembly and budding. J Lipid Res 2024; 65:100512. [PMID: 38295986 PMCID: PMC10909612 DOI: 10.1016/j.jlr.2024.100512] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 03/02/2024] Open
Abstract
Ebola virus (EBOV) causes severe hemorrhagic fever in humans and is lethal in a large percentage of those infected. The EBOV matrix protein viral protein 40 kDa (VP40) is a peripheral binding protein that forms a shell beneath the lipid bilayer in virions and virus-like particles (VLPs). VP40 is required for virus assembly and budding from the host cell plasma membrane. VP40 is a dimer that can rearrange into oligomers at the plasma membrane interface, but it is unclear how these structures form and how they are stabilized. We therefore investigated the ability of VP40 to form stable oligomers using in vitro and cellular assays. We characterized two lysine-rich regions in the VP40 C-terminal domain (CTD) that bind phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and play distinct roles in lipid binding and the assembly of the EBOV matrix layer. The extensive analysis of VP40 with and without lipids by hydrogen deuterium exchange mass spectrometry revealed that VP40 oligomers become extremely stable when VP40 binds PI(4,5)P2. The PI(4,5)P2-induced stability of VP40 dimers and oligomers is a critical factor in VP40 oligomerization and release of VLPs from the plasma membrane. The two lysine-rich regions of the VP40 CTD have different roles with respect to interactions with plasma membrane phosphatidylserine (PS) and PI(4,5)P2. CTD region 1 (Lys221, Lys224, and Lys225) interacts with PI(4,5)P2 more favorably than PS and is important for VP40 extent of oligomerization. In contrast, region 2 (Lys270, Lys274, Lys275, and Lys279) mediates VP40 oligomer stability via lipid interactions and has a more prominent role in release of VLPs.
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Affiliation(s)
- Kristen A Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Melissa R Budicini
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL, USA
| | - Tej Sharma
- Department of Physics, Florida International University, Miami, FL, USA
| | - Sarah Urata
- Department of Medicine, University of California San Diego, San Diego, CA, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Sheng Li
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN, USA.
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Hofstadter WA, Tsopurashvili E, Cristea IM. Viral regulation of organelle membrane contact sites. PLoS Biol 2024; 22:e3002529. [PMID: 38442090 PMCID: PMC10914265 DOI: 10.1371/journal.pbio.3002529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
At the core of organelle functions lies their ability and need to form dynamic organelle-organelle networks that drive intracellular communication and coordination of cellular pathways. These networks are facilitated by membrane contact sites (MCSs) that promote both intra-organelle and inter-organelle communication. Given their multiple functions, MCSs and the proteins that form them are commonly co-opted by viruses during infection to promote viral replication. This Essay discusses mechanisms acquired by diverse human viruses to regulate MCS functions in either proviral processes or host defense. It also examines techniques used for examining MCSs in the context of viral infections.
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Affiliation(s)
- William A. Hofstadter
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Elene Tsopurashvili
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ileana M. Cristea
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
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Saeed M, Alamri MA, Rashid MAR, Javed MR, Azeem F, Bashir Z, Alanzi AR, Muhseen ZT, Almusallam SY, Hussain K. Identification of novel inhibitors against VP40 protein of Marburg virus by integrating molecular modeling and dynamics approaches. J Biomol Struct Dyn 2024:1-14. [PMID: 38178383 DOI: 10.1080/07391102.2023.2300134] [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: 05/29/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
Marburg virus (MV) is a highly etiological agent of haemorrhagic fever in humans and has spread across the world. Its outbreaks caused a 23-90% human death rate. However, there are currently no authorized preventive or curative measures yet. VP40 is the MV matrix protein, which builds protein shell underneath the viral envelope and confers hallmark filamentous. VP40 alone is able to induce assembly and budding of filamentous virus-like particles (VLPs), which resemble authentic virions. As a result, this research is credited with clarifying the function of VP40 and leading to the discovery of new therapeutic targets effective in combating MV disease (MVD). Virtual screening, molecular docking and molecular dynamics (MD) simulation were used to find the putative active chemicals based on a 3D pharmacophore model of the protein's active site cavity. Initially, andrographidine-C, a potent inhibitor was selected for the development of the pharmacophore model. Later, a library of 30,000 compounds along with the andrographidine-C was docked against VP40 protein. Three best hits including avanafil, diuvaretin and macrourone were subjected to further MD simulation analysis, as these compounds had better binding affinities as compared to andrographidine-C. Furthermore, throughout the 100 ns simulations, the back bone of VP40 protein in presence of avanafil, diuvaretin and macrourone remained stable which was further validated by MM-PBSA analysis. Additionally, all of these compounds depict maximum drug-like properties. The predicted drugs based on the ligand, avanafil, diuvaretin and macrourone could be exploited and developed as an alternative or complementary therapy for the treatment of MVD.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Muhammad Saeed
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Mubarak A Alamri
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | | | - Muhammad Rizwan Javed
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Farrukh Azeem
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Zarmina Bashir
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Abdullah R Alanzi
- Department of Pharmacogonsy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | | | - Shahad Youseff Almusallam
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Khadim Hussain
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
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Dai J, Feng Y, Liao Y, Tan L, Sun Y, Song C, Qiu X, Ding C. ESCRT machinery and virus infection. Antiviral Res 2024; 221:105786. [PMID: 38147902 DOI: 10.1016/j.antiviral.2023.105786] [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: 10/25/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
The endosomal sorting complex required for transport (ESCRT) machinery plays a significant role in the spread of human viruses. However, our understanding of how the host ESCRT machinery responds to viral infection remains limited. Emerging evidence suggests that the ESCRT machinery can be hijacked by viruses of different families to enhance their replication. Throughout their life cycle, these viruses can interfere with or exploit ESCRT-mediated physiological processes to increase their chances of infecting the host. In contrast, to counteract virus infection, the interferon-stimulated gene 15 (ISG15) or the E3 ISG15-protein ligase (HERC5) system within the infected cells is activated to degrade the ESCRT proteins. Many retroviral and RNA viral proteins have evolved "late (L) domain" motifs, which enable them to recruit host ESCRT subunit proteins to facilitate virus transport, replication, budding, mature, and even endocytosis, Therefore, the L domain motifs and ESCRT subunit proteins could serve as promising drug targets for antiviral therapy. This review investigated the composition and essential functions of the ESCRT, shedding light on the impact of ESCRT subunits and viral L domain motifs on the replication of viruses. Furthermore, the antiviral effects facilitated by the ESCRT machinery have been investigated, aiming to provide valuable insights to guide the development and utilization of antiviral drugs.
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Affiliation(s)
- Jun Dai
- Experimental Animal Center, Zunyi Medical University, Zunyi, 563099, China; Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Yiyi Feng
- Laboratory of Veterinary Microbiology and Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning, 530004, Guangxi, China.
| | - Ying Liao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Lei Tan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Yingjie Sun
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Cuiping Song
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Xusheng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
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Wang C, Chen Y, Hu S, Liu X. Insights into the function of ESCRT and its role in enveloped virus infection. Front Microbiol 2023; 14:1261651. [PMID: 37869652 PMCID: PMC10587442 DOI: 10.3389/fmicb.2023.1261651] [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: 07/19/2023] [Accepted: 09/20/2023] [Indexed: 10/24/2023] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) is an essential molecular machinery in eukaryotic cells that facilitates the invagination of endosomal membranes, leading to the formation of multivesicular bodies (MVBs). It participates in various cellular processes, including lipid bilayer remodeling, cytoplasmic separation, autophagy, membrane fission and re-modeling, plasma membrane repair, as well as the invasion, budding, and release of certain enveloped viruses. The ESCRT complex consists of five complexes, ESCRT-0 to ESCRT-III and VPS4, along with several accessory proteins. ESCRT-0 to ESCRT-II form soluble complexes that shuttle between the cytoplasm and membranes, mainly responsible for recruiting and transporting membrane proteins and viral particles, as well as recruiting ESCRT-III for membrane neck scission. ESCRT-III, a soluble monomer, directly participates in vesicle scission and release, while VPS4 hydrolyzes ATP to provide energy for ESCRT-III complex disassembly, enabling recycling. Studies have confirmed the hijacking of ESCRT complexes by enveloped viruses to facilitate their entry, replication, and budding. Recent research has focused on the interaction between various components of the ESCRT complex and different viruses. In this review, we discuss how different viruses hijack specific ESCRT regulatory proteins to impact the viral life cycle, aiming to explore commonalities in the interaction between viruses and the ESCRT system.
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Affiliation(s)
- Chunxuan Wang
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yu Chen
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shunlin Hu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Xiufan Liu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
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Narkhede YB, Bhardwaj A, Motsa BB, Saxena R, Sharma T, Chapagain PP, Stahelin RV, Wiest O. Elucidating Residue-Level Determinants Affecting Dimerization of Ebola Virus Matrix Protein Using High-Throughput Site Saturation Mutagenesis and Biophysical Approaches. J Phys Chem B 2023; 127:6449-6461. [PMID: 37458567 DOI: 10.1021/acs.jpcb.3c01759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The Ebola virus (EBOV) is a filamentous virus that acquires its lipid envelope from the plasma membrane of the host cell it infects. EBOV assembly and budding from the host cell plasma membrane are mediated by a peripheral protein, known as the matrix protein VP40. VP40 is a 326 amino acid protein with two domains that are loosely linked. The VP40 N-terminal domain (NTD) contains a hydrophobic α-helix, which mediates VP40 dimerization. The VP40 C-terminal domain has a cationic patch, which mediates interactions with anionic lipids and a hydrophobic region that mediates VP40 dimer-dimer interactions. The VP40 dimer is necessary for trafficking to the plasma membrane inner leaflet and interactions with anionic lipids to mediate the VP40 assembly and oligomerization. Despite significant structural information available on the VP40 dimer structure, little is known on how the VP40 dimer is stabilized and how residues outside the NTD hydrophobic portion of the α-helical dimer interface contribute to dimer stability. To better understand how VP40 dimer stability is maintained, we performed computational studies using per-residue energy decomposition and site saturation mutagenesis. These studies revealed a number of novel keystone residues for VP40 dimer stability just adjacent to the α-helical dimer interface as well as distant residues in the VP40 CTD that can stabilize the VP40 dimer form. Experimental studies with representative VP40 mutants in vitro and in cells were performed to test computational predictions that reveal residues that alter VP40 dimer stability. Taken together, these studies provide important biophysical insights into VP40 dimerization and may be useful in strategies to weaken or alter the VP40 dimer structure as a means of inhibiting the EBOV assembly.
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Affiliation(s)
- Yogesh B Narkhede
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Atul Bhardwaj
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Balindile B Motsa
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Roopashi Saxena
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | | | | | - Robert V Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Olaf Wiest
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Simonetti L, Nilsson J, McInerney G, Ivarsson Y, Davey NE. SLiM-binding pockets: an attractive target for broad-spectrum antivirals. Trends Biochem Sci 2023; 48:420-427. [PMID: 36623987 DOI: 10.1016/j.tibs.2022.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/09/2022] [Accepted: 12/15/2022] [Indexed: 01/08/2023]
Abstract
Short linear motif (SLiM)-mediated interactions offer a unique strategy for viral intervention due to their compact interfaces, ease of convergent evolution, and key functional roles. Consequently, many viruses extensively mimic host SLiMs to hijack or deregulate cellular pathways and the same motif-binding pocket is often targeted by numerous unrelated viruses. A toolkit of therapeutics targeting commonly mimicked SLiMs could provide prophylactic and therapeutic broad-spectrum antivirals and vastly improve our ability to treat ongoing and future viral outbreaks. In this opinion article, we discuss the therapeutic relevance of SLiMs, advocating their suitability as targets for broad-spectrum antiviral inhibitors.
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Affiliation(s)
| | - Jakob Nilsson
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Gerald McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ylva Ivarsson
- Department of Chemistry - BMC, Husargatan 3, 751 23 Uppsala, Sweden
| | - Norman E Davey
- Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK.
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Characterization of Bovine Foamy Virus Gag Late Assembly Domain Motifs and Their Role in Recruiting ESCRT for Budding. Viruses 2022; 14:v14030522. [PMID: 35336929 PMCID: PMC8952818 DOI: 10.3390/v14030522] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 12/26/2022] Open
Abstract
A large number of retroviruses, such as human immunodeficiency virus (HIV) and prototype foamy virus (PFV), recruit the endosomal sorting complex required for transport (ESCRT) through the late domain (L domain) on the Gag structural protein for virus budding. However, little is known about the molecular mechanism of bovine foamy virus (BFV) budding. In the present study, we report that BFV recruits ESCRT for budding through the L domain of Gag. Specifically, knockdown of VPS4 (encoding vacuolar protein sorting 4), ALIX (encoding ALG-2-interacting protein X), and TSG101 (encoding tumor susceptibility 101) indicated that BFV uses ESCRT for budding. Mutational analysis of BFV Gag (BGag) showed that, in contrast to the classical L domain motifs, BGag contains two motifs, P56LPI and Y103GPL, with L domain functions. In addition, the two L domains are necessary for the cytoplasmic localization of BGag, which is important for effective budding. Furthermore, we demonstrated that the functional site of Alix is V498 in the V domain and the functional site of Tsg101 is N69 in the UBC-like domain for BFV budding. Taken together, these results demonstrate that BFV recruits ESCRT for budding through the PLPI and YGPL L domain motifs in BGag.
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WWOX-Mediated Degradation of AMOTp130 Negatively Affects Egress of Filovirus VP40 VLPs. J Virol 2022; 96:e0202621. [PMID: 35107375 DOI: 10.1128/jvi.02026-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ebola (EBOV) and Marburg (MARV) viruses continue to emerge and cause severe hemorrhagic disease in humans. A comprehensive understanding of the filovirus-host interplay will be crucial for identifying and developing antiviral strategies. The filoviral VP40 matrix protein drives virion assembly and egress, in part by recruiting specific WW-domain-containing host interactors via its conserved PPxY Late (L) domain motif to positively regulate virus egress and spread. In contrast to these positive regulators of virus budding, a growing list of WW-domain-containing interactors that negatively regulate virus egress and spread have been identified, including BAG3, YAP/TAZ and WWOX. In addition to host WW-domain regulators of virus budding, host PPxY-containing proteins also contribute to regulating this late stage of filovirus replication. For example, angiomotin (AMOT) is a multi-PPxY-containing host protein that functionally interacts with many of the same WW-domain-containing proteins that regulate virus egress and spread. In this report, we demonstrate that host WWOX, which negatively regulates egress of VP40 VLPs and recombinant VSV-M40 virus, interacts with and suppresses the expression of AMOT. We found that WWOX disrupts AMOT's scaffold-like tubular distribution and reduces AMOT localization at the plasma membrane via lysosomal degradation. In sum, our findings reveal an indirect and novel mechanism by which modular PPxY/WW-domain interactions between AMOT and WWOX regulate PPxY-mediated egress of filovirus VP40 VLPs. A better understanding of this modular network and competitive nature of protein-protein interactions will help to identify new antiviral targets and therapeutic strategies. IMPORTANCE Filoviruses (Ebola [EBOV] and Marburg [MARV]) are zoonotic, emerging pathogens that cause outbreaks of severe hemorrhagic fever in humans. A fundamental understanding of the virus-host interface is critical for understanding the biology of these viruses and for developing future strategies for therapeutic intervention. Here, we reveal a novel mechanism by which host proteins WWOX and AMOTp130 interact with each other and with the EBOV matrix protein VP40 to regulate VP40-mediated egress of virus like particles (VLPs). Our results highlight the biological impact of competitive interplay of modular virus-host interactions on both the virus lifecycle and the host cell.
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12
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Identification of novel chemical compounds targeting filovirus VP40-mediated particle production. Antiviral Res 2022; 199:105267. [DOI: 10.1016/j.antiviral.2022.105267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 02/13/2022] [Accepted: 02/22/2022] [Indexed: 11/22/2022]
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Roles of ESCRT proteins (ALIX and CHIMP4A) and their interplay with ISG15 during tick-borne flavivirus infection. J Virol 2021; 96:e0162421. [PMID: 34851141 PMCID: PMC8826915 DOI: 10.1128/jvi.01624-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Flaviviruses are usually transmitted to humans via mosquito or tick bites. During infection, virus replication and assembly, whose cellular sites are relatively close, are controlled by virus proteins and a diverse range of host proteins. By siRNA-mediated gene silencing, we showed that ALIX and CHMP4A, two members of the host endosomal sorting complex required for transport (ESCRT) protein machinery, are required during flavivirus infection. Using cell lines expressing subgenomic replicons and replicon virus-like particles, we demonstrated specific roles for ALIX and CHMP4A in viral replication and assembly, respectively. Employing biochemical and imaging methodology, we showed that the ESCRT proteins are recruited by a putative specific late (L) domain motif LYXLA within the NS3 protein of tick-borne flaviviruses. Furthermore, to counteract the recruitment of ESCRT proteins, the host cells may elicit defense mechanisms. We found that ectopic expression of the interferon-stimulated gene 15 (ISG15) or the E3 ISG15-protein ligase (HERC5) reduced virus replication by suppressing the positive effects of ALIX and CHMP4A. Collectively, these results have provided new insights into flavivirus-host cell interactions that function as checkpoints, including the NS3 and the ESCRT proteins, the ISG15 and the ESCRT proteins, at essential stages of the virus life cycle. IMPORTANCE Flaviviruses are important zoonotic viruses with high fatality rates worldwide. Here, we report that during infection, the virus employs members of ESCRT proteins for virus replication and assembly. Among the ESCRT proteins, ALIX acts during virus replication, while CHMP4A is required during virus assembly. Another important ESCRT protein, TSG101, is not required for virus production. The ESCRT, complex, ALIX-CHMP4A, is recruited to NS3 through their interactions with the putative L domain motif of NS3, while CHMP4A is recruited to E. In addition, we demonstrate the antiviral mechanism of ISG15 and HERC5, which degrades ALIX and CHIMP4A, indirectly targets virus infection. In summary, we reveal host-dependency factors supporting flavivirus infection, but these factors may also be targeted by antiviral host effector mechanisms.
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Mechanistic roles of tyrosine phosphorylation in reversible amyloids, autoinhibition, and endosomal membrane association of ALIX. J Biol Chem 2021; 297:101328. [PMID: 34688656 PMCID: PMC8577116 DOI: 10.1016/j.jbc.2021.101328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 11/26/2022] Open
Abstract
Human apoptosis-linked gene-2 interacting protein X (ALIX), a versatile adapter protein, regulates essential cellular processes by shuttling between late endosomal membranes and the cytosol, determined by its interactions with Src kinase. Here, we investigate the molecular basis of these transitions and the effects of tyrosine phosphorylation on the interplay between structure, assembly, and intramolecular and intermolecular interactions of ALIX. As evidenced by transmission electron microscopy, fluorescence and circular dichroism spectroscopy, the proline-rich domain of ALIX, which encodes binding epitopes of multiple cellular partners, formed rope-like β-sheet–rich reversible amyloid fibrils that dissolved upon Src-mediated phosphorylation and were restored on protein-tyrosine phosphatase 1B–mediated dephosphorylation of its conserved tyrosine residues. Analyses of the Bro1 domain of ALIX by solution NMR spectroscopy elucidated the conformational changes originating from its phosphorylation by Src and established that Bro1 binds to hyperphosphorylated proline-rich domain and to analogs of late endosomal membranes via its highly basic surface. These results uncover the autoinhibition mechanism that relocates ALIX to the cytosol and the diverse roles played by tyrosine phosphorylation in cellular and membrane functions of ALIX.
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15
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Banerjee G, Shokeen K, Chakraborty N, Agarwal S, Mitra A, Kumar S, Banerjee P. Modulation of immune response in Ebola virus disease. Curr Opin Pharmacol 2021; 60:158-167. [PMID: 34425392 DOI: 10.1016/j.coph.2021.07.004] [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: 04/04/2021] [Revised: 06/29/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
Ebola virus disease targets and destroys immune cells, including macrophages and dendritic cells, leading to impairment of host response. After infection, a combination of strategies including alteration and evasion of immune response culminating in a strong inflammatory response can lead to multi-organ failure and death in most infected patients. This review discusses immune response dynamics, mainly focusing on how Ebola manipulates innate and adaptive immune responses and strategizes to thwart host immune responses. We also discuss the challenges and prospects of developing therapeutics and vaccines against Ebola.
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Affiliation(s)
- Goutam Banerjee
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Kamal Shokeen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Nilanjan Chakraborty
- Department of Microbiology, Adamas University, Kolkata, West Bengal, 700126, India
| | - Saumya Agarwal
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Arindam Mitra
- Department of Microbiology, Adamas University, Kolkata, West Bengal, 700126, India.
| | - Sachin Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
| | - Pratik Banerjee
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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16
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The Role of Exosome and the ESCRT Pathway on Enveloped Virus Infection. Int J Mol Sci 2021; 22:ijms22169060. [PMID: 34445766 PMCID: PMC8396519 DOI: 10.3390/ijms22169060] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 08/20/2021] [Accepted: 08/20/2021] [Indexed: 02/06/2023] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) system consists of peripheral membrane protein complexes ESCRT-0, -I, -II, -III VPS4-VTA1, and ALIX homodimer. This system plays an important role in the degradation of non-essential or dangerous plasma membrane proteins, the biogenesis of lysosomes and yeast vacuoles, the budding of most enveloped viruses, and promoting membrane shedding of cytokinesis. Recent results show that exosomes and the ESCRT pathway play important roles in virus infection. This review mainly focuses on the roles of exosomes and the ESCRT pathway in virus assembly, budding, and infection of enveloped viruses. The elaboration of the mechanism of exosomes and the ESCRT pathway in some enveloped viruses provides important implications for the further study of the infection mechanism of other enveloped viruses.
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17
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Johnson KA, Bhattarai N, Budicini MR, LaBonia CM, Baker SCB, Gerstman BS, Chapagain PP, Stahelin RV. Cysteine Mutations in the Ebolavirus Matrix Protein VP40 Promote Phosphatidylserine Binding by Increasing the Flexibility of a Lipid-Binding Loop. Viruses 2021; 13:1375. [PMID: 34372582 PMCID: PMC8310056 DOI: 10.3390/v13071375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/25/2022] Open
Abstract
Ebolavirus (EBOV) is a negative-sense RNA virus that causes severe hemorrhagic fever in humans. The matrix protein VP40 facilitates viral budding by binding to lipids in the host cell plasma membrane and driving the formation of filamentous, pleomorphic virus particles. The C-terminal domain of VP40 contains two highly-conserved cysteine residues at positions 311 and 314, but their role in the viral life cycle is unknown. We therefore investigated the properties of VP40 mutants in which the conserved cysteine residues were replaced with alanine. The C311A mutation significantly increased the affinity of VP40 for membranes containing phosphatidylserine (PS), resulting in the assembly of longer virus-like particles (VLPs) compared to wild-type VP40. The C314A mutation also increased the affinity of VP40 for membranes containing PS, albeit to a lesser degree than C311A. The double mutant behaved in a similar manner to the individual mutants. Computer modeling revealed that both cysteine residues restrain a loop segment containing lysine residues that interact with the plasma membrane, but Cys311 has the dominant role. Accordingly, the C311A mutation increases the flexibility of this membrane-binding loop, changes the profile of hydrogen bonding within VP40 and therefore binds to PS with greater affinity. This is the first evidence that mutations in VP40 can increase its affinity for biological membranes and modify the length of Ebola VLPs. The Cys311 and Cys314 residues therefore play an important role in dynamic interactions at the plasma membrane by modulating the ability of VP40 to bind PS.
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Affiliation(s)
- Kristen A. Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
| | - Melissa R. Budicini
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Carolyn M. LaBonia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Sarah Catherine B. Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- The Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- The Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
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18
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Angiomotin Counteracts the Negative Regulatory Effect of Host WWOX on Viral PPxY-Mediated Egress. J Virol 2021; 95:JVI.00121-21. [PMID: 33536174 PMCID: PMC8103691 DOI: 10.1128/jvi.00121-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Filoviridae family members Ebola (EBOV) and Marburg (MARV) viruses and Arenaviridae family member Lassa virus (LASV) are emerging pathogens that can cause hemorrhagic fever and high rates of mortality in humans. A better understanding of the interplay between these viruses and the host will inform about the biology of these pathogens, and may lead to the identification of new targets for therapeutic development. Notably, expression of the filovirus VP40 and LASV Z matrix proteins alone drives assembly and egress of virus-like particles (VLPs). The conserved PPxY Late (L) domain motifs in the filovirus VP40 and LASV Z proteins play a key role in the budding process by mediating interactions with select host WW-domain containing proteins that then regulate virus egress and spread. To identify the full complement of host WW-domain interactors, we utilized WT and PPxY mutant peptides from EBOV and MARV VP40 and LASV Z proteins to screen an array of GST-WW-domain fusion proteins. We identified WW domain-containing oxidoreductase (WWOX) as a novel PPxY-dependent interactor, and we went on to show that full-length WWOX physically interacts with eVP40, mVP40 and LASV Z to negatively regulate egress of VLPs and of a live VSV/Ebola recombinant virus (M40). Interestingly, WWOX is a versatile host protein that regulates multiple signaling pathways and cellular processes via modular interactions between its WW-domains and PPxY motifs of select interacting partners, including host angiomotin (AMOT). Notably, we demonstrated recently that expression of endogenous AMOT not only positively regulates egress of VLPs, but also promotes egress and spread of live EBOV and MARV. Toward the mechanism of action, we show that the competitive and modular interplay among WWOX-AMOT-VP40/Z regulates VLP and M40 virus egress. Thus, WWOX is the newest member of an emerging group of host WW-domain interactors (e.g. BAG3; YAP/TAZ) that negatively regulate viral egress. These findings further highlight the complex interplay of virus-host PPxY/WW-domain interactions and their potential impact on the biology of both the virus and the host during infection.Author Summary Filoviruses (Ebola [EBOV] and Marburg [MARV]) and arenavirus (Lassa virus; LASV) are zoonotic, emerging pathogens that cause outbreaks of severe hemorrhagic fever in humans. A fundamental understanding of the virus-host interface is critical for understanding the biology of these viruses and for developing future strategies for therapeutic intervention. Here, we identified host WW-domain containing protein WWOX as a novel interactor with VP40 and Z, and showed that WWOX inhibited budding of VP40/Z virus-like particles (VLPs) and live virus in a PPxY/WW-domain dependent manner. Our findings are important to the field as they expand the repertoire of host interactors found to regulate PPxY-mediated budding of RNA viruses, and further highlight the competitive interplay and modular virus-host interactions that impact both the virus lifecycle and the host cell.
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19
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Dicker K, Järvelin AI, Garcia-Moreno M, Castello A. The importance of virion-incorporated cellular RNA-Binding Proteins in viral particle assembly and infectivity. Semin Cell Dev Biol 2021; 111:108-118. [PMID: 32921578 PMCID: PMC7482619 DOI: 10.1016/j.semcdb.2020.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 12/14/2022]
Abstract
RNA is a central molecule in RNA virus biology due to its dual function as messenger and genome. However, the small number of proteins encoded by viral genomes is insufficient to enable virus infection. Hence, viruses hijack cellular RNA-binding proteins (RBPs) to aid replication and spread. In this review we discuss the 'knowns' and 'unknowns' regarding the contribution of host RBPs to the formation of viral particles and the initial steps of infection in the newly infected cell. Through comparison of the virion proteomes of ten different human RNA viruses, we confirm that a pool of cellular RBPs are typically incorporated into viral particles. We describe here illustrative examples supporting the important functions of these RBPs in viral particle formation and infectivity and we propose that the role of host RBPs in these steps can be broader than previously anticipated. Understanding how cellular RBPs regulate virus infection can lead to the discovery of novel therapeutic targets against viruses.
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Affiliation(s)
- Kate Dicker
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Aino I Järvelin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Manuel Garcia-Moreno
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Alfredo Castello
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK; MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK.
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20
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Ubiquitin Ligase SMURF2 Interacts with Filovirus VP40 and Promotes Egress of VP40 VLPs. Viruses 2021; 13:v13020288. [PMID: 33673144 PMCID: PMC7918931 DOI: 10.3390/v13020288] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/07/2021] [Accepted: 02/09/2021] [Indexed: 01/17/2023] Open
Abstract
Filoviruses Ebola (EBOV) and Marburg (MARV) are devastating high-priority pathogens capable of causing explosive outbreaks with high human mortality rates. The matrix proteins of EBOV and MARV, as well as eVP40 and mVP40, respectively, are the key viral proteins that drive virus assembly and egress and can bud independently from cells in the form of virus-like particles (VLPs). The matrix proteins utilize proline-rich Late (L) domain motifs (e.g., PPxY) to hijack specific host proteins that contain WW domains, such as the HECT family E3 ligases, to facilitate the last step of virus–cell separation. We identified E3 ubiquitin ligase Smad Ubiquitin Regulatory Factor 2 (SMURF2) as a novel interactor with VP40 that positively regulates VP40 VLP release. Our results show that eVP40 and mVP40 interact with the three WW domains of SMURF2 via their PPxY motifs. We provide evidence that the eVP40–SMURF2 interaction is functional as the expression of SMURF2 positively regulates VLP egress, while siRNA knockdown of endogenous SMURF2 decreases VLP budding compared to controls. In sum, our identification of novel interactor SMURF2 adds to the growing list of identified host proteins that can regulate PPxY-mediated egress of VP40 VLPs. A more comprehensive understanding of the modular interplay between filovirus VP40 and host proteins may lead to the development of new therapies to combat these deadly infections.
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21
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The Carboxyl Terminus of the Porcine Circovirus Type 2 Capsid Protein Is Critical to Virus-Like Particle Assembly, Cell Entry, and Propagation. J Virol 2020; 94:JVI.00042-20. [PMID: 32075927 DOI: 10.1128/jvi.00042-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 02/11/2020] [Indexed: 11/20/2022] Open
Abstract
The capsid protein (Cap) is the sole structural protein and the main antigen of porcine circovirus type 2 (PCV2). Structural loops of the Cap play crucial roles in viral genome packaging, capsid assembly, and virus-host interactions. Although the molecular mechanisms are yet unknown, the carboxyl terminus (CT) of the PCV2 Cap is known to play critical roles in the evolution, pathogenesis, and proliferation of this virus. In this study, we investigated functions of CT. Removal of this loop leads to abrogation of the in vitro Cap self-assembly into virus-like particles (VLPs). Likewise, the mutated virus resists rescue from PK15 cell culture. A conserved PXXP motif in the CT is dispensable for VLP assembly and subsequent cell entry. However, its removal leads to the subsequent failure of virus rescued from PK15 cells. Furthermore, substituting either the PCV1 counterpart or an AXXA for the PXXP motif still supports virus rescue from cell culture but results in a dramatic decrease in viral titers compared with wild type. In particular, a strictly conserved residue (227K) in the CT is essential for VLP entry into PK15 cells, and its mutation to alanine greatly attenuates cell entry of the VLPs, supporting a mechanism for the failure to rescue a mutated PCV2 infectious DNA clone (K227A) from PK15 cell culture. These results suggest the CT of the PCV2 Cap plays critical roles in virus assembly, viral-host cell interaction(s), and virus propagation in vitro IMPORTANCE The carboxyl terminus (CT) of porcine circovirus type 2 (PCV2) capsid protein (Cap) was previously reported to be associated with immunorecognition, alterations of viral titer in swine sera, and pathogenicity. However, the molecular mechanisms underlying these effects remain unknown. In this study, roles of the critical residues and motifs of the CT are investigated with respect to virus-like particle (VLP) assembly, cell entry, and viral proliferation. The results revealed that the positively charged 227K of the CT is essential for both cell entry of PCV2 VLPs and virus proliferation. Our findings, therefore, suggest that the CT should be considered one of the key epitopes, recognized by neutralizing antibodies, for vaccine design and a target for drug development to prevent PCV2-associated diseases (PCVADs). Furthermore, it is important to respect the function of 227K for its role in cell entry if using either PCV2 VLPs for nanoscale DNA/drug cell delivery or using PCV2 VLPs to display a variety of foreign epitopes for immunization.
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22
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The Integrity of the YxxL Motif of Ebola Virus VP24 Is Important for the Transport of Nucleocapsid-Like Structures and for the Regulation of Viral RNA Synthesis. J Virol 2020; 94:JVI.02170-19. [PMID: 32102881 DOI: 10.1128/jvi.02170-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 02/15/2020] [Indexed: 12/15/2022] Open
Abstract
While it is well appreciated that late domains in the viral matrix proteins are crucial to mediate efficient virus budding, little is known about roles of late domains in the viral nucleocapsid proteins. Here, we characterized the functional relevance of a YxxL motif with potential late-domain function in the Ebola virus nucleocapsid protein VP24. Mutations in the YxxL motif had two opposing effects on the functions of VP24. On the one hand, the mutation affected the regulatory function of VP24 in viral RNA transcription and replication, which correlated with an increased incorporation of minigenomes into released transcription- and replication-competent virus-like particles (trVLPs). Consequently, cells infected with those trVLPs showed higher levels of viral transcription. On the other hand, mutations of the YxxL motif greatly impaired the intracellular transport of nucleocapsid-like structures (NCLSs) composed of the viral proteins NP, VP35, and VP24 and the length of released trVLPs. Attempts to rescue recombinant Ebola virus expressing YxxL-deficient VP24 failed, underlining the importance of this motif for the viral life cycle.IMPORTANCE Ebola virus (EBOV) causes a severe fever with high case fatality rates and, so far, no available specific therapy. Understanding the interplay between viral and host proteins is important to identify new therapeutic approaches. VP24 is one of the essential nucleocapsid components and is necessary to regulate viral RNA synthesis and condense viral nucleocapsids before their transport to the plasma membrane. Our functional analyses of the YxxL motif in VP24 suggested that it serves as an interface between nucleocapsid-like structures (NCLSs) and cellular proteins, promoting intracellular transport of NCLSs in an Alix-independent manner. Moreover, the YxxL motif is necessary for the inhibitory function of VP24 in viral RNA synthesis. A failure to rescue EBOV encoding VP24 with a mutated YxxL motif indicated that the integrity of the YxxL motif is essential for EBOV growth. Thus, this motif might represent a potential target for antiviral interference.
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23
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Grabowska K, Wąchalska M, Graul M, Rychłowski M, Bieńkowska-Szewczyk K, Lipińska AD. Alphaherpesvirus gB Homologs Are Targeted to Extracellular Vesicles, but They Differentially Affect MHC Class II Molecules. Viruses 2020; 12:v12040429. [PMID: 32290097 PMCID: PMC7232241 DOI: 10.3390/v12040429] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/24/2020] [Accepted: 04/08/2020] [Indexed: 12/14/2022] Open
Abstract
Herpesvirus envelope glycoprotein B (gB) is one of the best-documented extracellular vesicle (EVs)-incorporated viral proteins. Regarding the sequence and structure conservation between gB homologs, we asked whether bovine herpesvirus-1 (BoHV-1) and pseudorabies virus (PRV)-encoded gB share the property of herpes simplex-1 (HSV-1) gB to be trafficked to EVs and affect major histocompatibility complex (MHC) class II. Our data highlight some conserved and differential features of the three gBs. We demonstrate that mature, fully processed BoHV-1 and PRV gBs localize to EVs isolated from constructed stable cell lines and EVs-enriched fractions from virus-infected cells. gB also shares the ability to co-localize with CD63 and MHC II in late endosomes. However, we report here a differential effect of the HSV-1, BoHV-1, and PRV glycoprotein on the surface MHC II levels, and MHC II loading to EVs in stable cell lines, which may result from their adverse ability to bind HLA-DR, with PRV gB being the most divergent. BoHV-1 and HSV-1 gB could retard HLA-DR exports to the plasma membrane. Our results confirm that the differential effect of gB on MHC II may require various mechanisms, either dependent on its complex formation or on inducing general alterations to the vesicular transport. EVs from virus-infected cells also contained other viral glycoproteins, like gD or gE, and they were enriched in MHC II. As shown for BoHV-1 gB- or BoHV-1-infected cell-derived vesicles, those EVs could bind anti-virus antibodies in ELISA, which supports the immunoregulatory potential of alphaherpesvirus gB.
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24
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Watanabe SM, Ehrlich LS, Strickland M, Li X, Soloveva V, Goff AJ, Stauft CB, Bhaduri-McIntosh S, Tjandra N, Carter C. Selective Targeting of Virus Replication by Proton Pump Inhibitors. Sci Rep 2020; 10:4003. [PMID: 32132561 PMCID: PMC7055211 DOI: 10.1038/s41598-020-60544-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 02/12/2020] [Indexed: 02/06/2023] Open
Abstract
Two proton pump inhibitors, tenatoprazole and esomeprazole, were previously shown to inhibit HIV-1 egress by blocking the interaction between Tsg101, a member of the ESCRT-I complex, and ubiquitin. Here, we deepen our understanding of prazole budding inhibition by studying a range of viruses in the presence of tenatoprazole. Furthermore, we investigate the relationship between the chemistry of prodrug activation and HIV-1 inhibition for diverse prazoles currently on the market. We report that tenatoprazole is capable of inhibiting the replication of members of the enveloped filo, alpha, and herpes virus families but not the flavivirus group and not the non-enveloped poliovirus. Another key finding is that prazole prodrugs must be activated inside the cell, while their rate of activation in vitro correlated to their efficacy in cells. Our study lays the groundwork for future efforts to repurpose prazole-based compounds as antivirals that are both broad-spectrum and selective in nature.
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Affiliation(s)
- Susan M Watanabe
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, 11794-5222, USA
| | - Lorna S Ehrlich
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, 11794-5222, USA
| | - Madeleine Strickland
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xiaofan Li
- Department of Pediatrics, Division of Infectious Diseases and Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Veronica Soloveva
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD, 21702-5011, USA
| | - Arthur J Goff
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD, 21702-5011, USA
| | - Charles B Stauft
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, 11794-5222, USA
| | - Sumita Bhaduri-McIntosh
- Department of Pediatrics, Division of Infectious Diseases and Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Nico Tjandra
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Carol Carter
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, 11794-5222, USA.
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25
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Han Z, Dash S, Sagum CA, Ruthel G, Jaladanki CK, Berry CT, Schwoerer MP, Harty NM, Freedman BD, Bedford MT, Fan H, Sidhu SS, Sudol M, Shtanko O, Harty RN. Modular mimicry and engagement of the Hippo pathway by Marburg virus VP40: Implications for filovirus biology and budding. PLoS Pathog 2020; 16:e1008231. [PMID: 31905227 PMCID: PMC6977764 DOI: 10.1371/journal.ppat.1008231] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 01/23/2020] [Accepted: 11/21/2019] [Indexed: 01/16/2023] Open
Abstract
Ebola (EBOV) and Marburg (MARV) are members of the Filoviridae family, which continue to emerge and cause sporadic outbreaks of hemorrhagic fever with high mortality rates. Filoviruses utilize their VP40 matrix protein to drive virion assembly and budding, in part, by recruitment of specific WW-domain-bearing host proteins via its conserved PPxY Late (L) domain motif. Here, we screened an array of 115 mammalian, bacterially expressed and purified WW-domains using a PPxY-containing peptide from MARV VP40 (mVP40) to identify novel host interactors. Using this unbiased approach, we identified Yes Associated Protein (YAP) and Transcriptional co-Activator with PDZ-binding motif (TAZ) as novel mVP40 PPxY interactors. YAP and TAZ function as downstream transcriptional effectors of the Hippo signaling pathway that regulates cell proliferation, migration and apoptosis. We demonstrate that ectopic expression of YAP or TAZ along with mVP40 leads to significant inhibition of budding of mVP40 VLPs in a WW-domain/PPxY dependent manner. Moreover, YAP colocalized with mVP40 in the cytoplasm, and inhibition of mVP40 VLP budding was more pronounced when YAP was localized predominantly in the cytoplasm rather than in the nucleus. A key regulator of YAP nuclear/cytoplasmic localization and function is angiomotin (Amot); a multi-PPxY containing protein that strongly interacts with YAP WW-domains. Interestingly, we found that expression of PPxY-containing Amot rescued mVP40 VLP egress from either YAP- or TAZ-mediated inhibition in a PPxY-dependent manner. Importantly, using a stable Amot-knockdown cell line, we found that expression of Amot was critical for efficient egress of mVP40 VLPs as well as egress and spread of authentic MARV in infected cell cultures. In sum, we identified novel negative (YAP/TAZ) and positive (Amot) regulators of MARV VP40-mediated egress, that likely function in part, via competition between host and viral PPxY motifs binding to modular host WW-domains. These findings not only impact our mechanistic understanding of virus budding and spread, but also may impact the development of new antiviral strategies. By screening an array of 115 mammalian WW-domains with the PPxY motif from MARV VP40 (mVP40), we identified YAP1 and TAZ, transcriptional effectors of the Hippo pathway, as mVP40 interactors, and demonstrated that ectopically expressed YAP1 or TAZ inhibited budding of mVP40 virus-like particles (VLPs) in a WW-domain/PPxY dependent manner. Angiomotin (Amot), a multi-PPxY containing regulator of YAP1 nuclear/cytoplasmic localization and function, rescued mVP40 VLP egress from either YAP1- or TAZ-mediated inhibition in a PPxY-dependent manner. Indeed, endogenous Amot expression was critical for egress of mVP40 VLPs and authentic MARV. In sum, we have revealed a link between the Hippo pathway and filovirus egress by identifying negative (YAP/TAZ) and positive (Amot) regulators of MARV VP40-mediated egress.
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Affiliation(s)
- Ziying Han
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Shantoshini Dash
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Cari A. Sagum
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas, Smithville, Texas, United States of America
| | - Gordon Ruthel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Chaitanya K. Jaladanki
- Department of Physiology and Mechanobiology Institute at National University of Singapore, Institute for Molecular and Cell Biology, IMCB, and Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Corbett T. Berry
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael P. Schwoerer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Nina M. Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Bruce D. Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Mark T. Bedford
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas, Smithville, Texas, United States of America
| | - Hao Fan
- Department of Physiology and Mechanobiology Institute at National University of Singapore, Institute for Molecular and Cell Biology, IMCB, and Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Sachdev S. Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Marius Sudol
- Department of Physiology and Mechanobiology Institute at National University of Singapore, Institute for Molecular and Cell Biology, IMCB, and Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Olena Shtanko
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Ronald N. Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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26
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[Molecular mechanisms of highly pathogenic viruses' replication and their applications for a novel drug discovery]. Uirusu 2020; 70:69-82. [PMID: 33967116 DOI: 10.2222/jsv.70.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Productive (lytic) replication of DNA viruses elicits host cell DNA damage responses, which cause both beneficial and detrimental effects on viral replication. Viruses utilize them and selectively cancel the 'noisy' downstream signaling pathways, leading to maintain high S-phase CDK activities required for viral replication. To achieve this fine tuning of cellular environment, herpesviruses encode many (>70) genes in their genome, which are expressed in a strictly regulated temporal cascade (immediate-early, early, and late). Here, I introduce and discuss how Epstein-Barr virus, an oncogenic herpesvirus, hijacks the cellular environment and adapt it for the progeny production.
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27
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Urata S, Ishikawa T, Yasuda J. Roles of YIGL sequence of Ebola virus VP40 on genome replication and particle production. J Gen Virol 2019; 100:1099-1111. [PMID: 31184566 DOI: 10.1099/jgv.0.001286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ebola virus (EBOV) VP40 is a major driving force of nascent virion production and a negative regulator of genome replication/transcription. Here, we showed that the YIGL sequence at the C-terminus of EBOV VP40 is important for virus-like particle (VLP) production and the regulation of genome replication/transcription. Accordingly, a mutation in the YIGL sequence caused defects in VLP production and genome replication/transcription. The residues I293 and L295 in the YIGL sequence were particularly critical for VLP production. Furthermore, an in silico analysis indicated that the amino acids surrounding the YIGL sequence contribute to intramolecular interactions within VP40. Among those surrounding residues, F209 was shown to be critical for VLP production. These results suggested that the VP40 YIGL sequence regulates two different viral replication steps, VLP production and genome replication/transcription, and the nearby residue F209 influences VLP production.
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Affiliation(s)
- Shuzo Urata
- Department of Emerging Infectious Diseasesn, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.,National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Takeshi Ishikawa
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Jiro Yasuda
- National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.,Graduate School of Biomedical Sciences and Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.,Department of Emerging Infectious Diseasesn, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
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28
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Pleet ML, DeMarino C, Stonier SW, Dye JM, Jacobson S, Aman MJ, Kashanchi F. Extracellular Vesicles and Ebola Virus: A New Mechanism of Immune Evasion. Viruses 2019; 11:v11050410. [PMID: 31052499 PMCID: PMC6563240 DOI: 10.3390/v11050410] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023] Open
Abstract
Ebola virus (EBOV) disease can result in a range of symptoms anywhere from virtually asymptomatic to severe hemorrhagic fever during acute infection. Additionally, spans of asymptomatic persistence in recovering survivors is possible, during which transmission of the virus may occur. In acute infection, substantial cytokine storm and bystander lymphocyte apoptosis take place, resulting in uncontrolled, systemic inflammation in affected individuals. Recently, studies have demonstrated the presence of EBOV proteins VP40, glycoprotein (GP), and nucleoprotein (NP) packaged into extracellular vesicles (EVs) during infection. EVs containing EBOV proteins have been shown to induce apoptosis in recipient immune cells, as well as contain pro-inflammatory cytokines. In this manuscript, we review the current field of knowledge on EBOV EVs including the mechanisms of their biogenesis, their cargo and their effects in recipient cells. Furthermore, we discuss some of the effects that may be induced by EBOV EVs that have not yet been characterized and highlight the remaining questions and future directions.
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Affiliation(s)
- Michelle L Pleet
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA.
| | - Catherine DeMarino
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA.
| | - Spencer W Stonier
- Department, Emergent BioSolutions, Gaithersburg, MD 20879, USA.
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA.
| | - John M Dye
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA.
| | - Steven Jacobson
- Viral Immunology Section, Neuroimmunology Branch, National Institute for Neurological Disease and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - M Javad Aman
- Department. Integrated BioTherapeutics, Inc., Gaithersburg, MD 20850, USA.
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA 20110, USA.
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29
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Xu S, Sui S, Zhang X, Pang B, Wan L, Pang D. Modulation of autophagy in human diseases strategies to foster strengths and circumvent weaknesses. Med Res Rev 2019; 39:1953-1999. [PMID: 30820989 DOI: 10.1002/med.21571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/20/2019] [Accepted: 02/05/2019] [Indexed: 12/19/2022]
Abstract
Autophagy is central to the maintenance of intracellular homeostasis across species. Accordingly, autophagy disorders are linked to a variety of diseases from the embryonic stage until death, and the role of autophagy as a therapeutic target has been widely recognized. However, autophagy-associated therapy for human diseases is still in its infancy and is supported by limited evidence. In this review, we summarize the landscape of autophagy-associated diseases and current autophagy modulators. Furthermore, we investigate the existing autophagy-associated clinical trials, analyze the obstacles that limit their progress, offer tactics that may allow barriers to be overcome along the way and then discuss the therapeutic potential of autophagy modulators in clinical applications.
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Affiliation(s)
- Shouping Xu
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China
| | - Shiyao Sui
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China
| | - Xianyu Zhang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China
| | - Boran Pang
- Department of Surgery, Rui Jin Hospital, Shanghai Key Laboratory of Gastric Neoplasm, Shanghai Institute of Digestive Surgery, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lin Wan
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China
| | - Da Pang
- Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China
- Heilongjiang Academy of Medical Sciences, Harbin, Heilongjcontrary, induction of autophagy elongiang, China
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30
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Gordon TB, Hayward JA, Marsh GA, Baker ML, Tachedjian G. Host and Viral Proteins Modulating Ebola and Marburg Virus Egress. Viruses 2019; 11:v11010025. [PMID: 30609802 PMCID: PMC6357148 DOI: 10.3390/v11010025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/21/2018] [Accepted: 01/01/2019] [Indexed: 12/11/2022] Open
Abstract
The filoviruses Ebolavirus and Marburgvirus are among the deadliest viral pathogens known to infect humans, causing emerging diseases with fatality rates of up to 90% during some outbreaks. The replication cycles of these viruses are comprised of numerous complex molecular processes and interactions with their human host, with one key feature being the means by which nascent virions exit host cells to spread to new cells and ultimately to a new host. This review focuses on our current knowledge of filovirus egress and the viral and host factors and processes that are involved. Within the virus, these factors consist of the major matrix protein, viral protein 40 (VP40), which is necessary and sufficient for viral particle release, and nucleocapsid and glycoprotein that interact with VP40 to promote egress. In the host cell, some proteins are hijacked by filoviruses in order to enhance virion budding capacity that include members of the family of E3 ubiquitin ligase and the endosomal sorting complexes required for transport (ESCRT) pathway, while others such as tetherin inhibit viral egress. An understanding of these molecular interactions that modulate viral particle egress provides an important opportunity to identify new targets for the development of antivirals to prevent and treat filovirus infections.
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Affiliation(s)
- Tamsin B Gordon
- Health Security Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia.
- Department of Microbiology, Monash University, Clayton, VIC 3168, Australia.
| | - Joshua A Hayward
- Health Security Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia.
- Department of Microbiology, Monash University, Clayton, VIC 3168, Australia.
| | - Glenn A Marsh
- Department of Microbiology, Monash University, Clayton, VIC 3168, Australia.
- CSIRO Australian Animal Health Laboratory, Health and Biosecurity Business Unit, Geelong, VIC 3220, Australia.
| | - Michelle L Baker
- CSIRO Australian Animal Health Laboratory, Health and Biosecurity Business Unit, Geelong, VIC 3220, Australia.
| | - Gilda Tachedjian
- Health Security Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia.
- Department of Microbiology, Monash University, Clayton, VIC 3168, Australia.
- Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne VIC 3010, Australia.
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3000, Australia.
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31
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Brandt J, Wendt L, Hoenen T. Structure and functions of the Ebola virus matrix protein VP40. Future Virol 2019. [DOI: 10.2217/fvl-2018-0162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The matrix protein VP40 of the highly pathogenic Ebola virus (EBOV), a member of the filovirus family, is the most abundant protein in EBOV virions. During the viral life cycle it mediates assembly and budding from the host cell, and is responsible for the characteristic filamentous shape of EBOV particles. In addition to this classical function as a matrix protein, VP40 was also shown to have a regulatory function in viral transcription. To enable these distinct functions, VP40 can adopt different oligomeric states, in particular, dimers, hexamers and ring-like octameric RNA-binding structures. This review describes the properties and functions of the EBOV matrix protein VP40 and how these different conformations of VP40 contribute to its diverse functions.
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Affiliation(s)
- Janine Brandt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald – Insel Riems, Germany
| | - Lisa Wendt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald – Insel Riems, Germany
| | - Thomas Hoenen
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald – Insel Riems, Germany
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32
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Han Z, Schwoerer MP, Hicks P, Liang J, Ruthel G, Berry CT, Freedman BD, Sagum CA, Bedford MT, Sidhu SS, Sudol M, Harty RN. Host Protein BAG3 is a Negative Regulator of Lassa VLP Egress. Diseases 2018; 6:diseases6030064. [PMID: 30011814 PMCID: PMC6163595 DOI: 10.3390/diseases6030064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 12/20/2022] Open
Abstract
Lassa fever virus (LFV) belongs to the Arenaviridae family and can cause acute hemorrhagic fever in humans. The LFV Z protein plays a central role in virion assembly and egress, such that independent expression of LFV Z leads to the production of virus-like particles (VLPs) that mimic egress of infectious virus. LFV Z contains both PTAP and PPPY L-domain motifs that are known to recruit host proteins that are important for mediating efficient virus egress and spread. The viral PPPY motif is known to interact with specific host WW-domain bearing proteins. Here we identified host WW-domain bearing protein BCL2 Associated Athanogene 3 (BAG3) as a LFV Z PPPY interactor using our proline-rich reading array of WW-domain containing mammalian proteins. BAG3 is a stress-induced molecular co-chaperone that functions to regulate cellular protein homeostasis and cell survival via Chaperone-Assisted Selective Autophagy (CASA). Similar to our previously published findings for the VP40 proteins of Ebola and Marburg viruses, our results using VLP budding assays, BAG3 knockout cells, and confocal microscopy indicate that BAG3 is a WW-domain interactor that negatively regulates egress of LFV Z VLPs, rather than promoting VLP release. Our results suggest that CASA and specifically BAG3 may represent a novel host defense mechanism, whereby BAG3 may dampen egress of several hemorrhagic fever viruses by interacting and interfering with the budding function of viral PPxY-containing matrix proteins.
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Affiliation(s)
- Ziying Han
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Michael P Schwoerer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Philip Hicks
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Jingjing Liang
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Gordon Ruthel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Corbett T Berry
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Bruce D Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Cari A Sagum
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas, Smithville, TX 78957, USA.
| | - Mark T Bedford
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas, Smithville, TX 78957, USA.
| | - Sachdev S Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, ON M1C 1A4, Canada.
| | - Marius Sudol
- Department of Physiology, Institute for Molecular and Cell Biology (IMCB, AStar), National University of Singapore, Singapore 119077, Singapore.
| | - Ronald N Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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33
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Wendt L, Kämper L, Schmidt ML, Mettenleiter TC, Hoenen T. Analysis of a Putative Late Domain Using an Ebola Virus Transcription and Replication-Competent Virus-Like Particle System. J Infect Dis 2018; 218:S355-S359. [DOI: 10.1093/infdis/jiy247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lisa Wendt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Lennart Kämper
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Marie Luisa Schmidt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Thomas C Mettenleiter
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Thomas Hoenen
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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34
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ESCRT machinery components are required for Orthobunyavirus particle production in Golgi compartments. PLoS Pathog 2018; 14:e1007047. [PMID: 29723305 PMCID: PMC5953487 DOI: 10.1371/journal.ppat.1007047] [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: 08/04/2017] [Revised: 05/15/2018] [Accepted: 04/18/2018] [Indexed: 01/10/2023] Open
Abstract
Peribunyaviridae is a large family of RNA viruses with several members that cause mild to severe diseases in humans and livestock. Despite their importance in public heath very little is known about the host cell factors hijacked by these viruses to support assembly and cell egress. Here we show that assembly of Oropouche virus, a member of the genus Orthobunyavirus that causes a frequent arboviral infection in South America countries, involves budding of virus particles toward the lumen of Golgi cisternae. As viral replication progresses, these Golgi subcompartments become enlarged and physically separated from Golgi stacks, forming Oropouche viral factory (Vfs) units. At the ultrastructural level, these virally modified Golgi cisternae acquire an MVB appearance, and while they lack typical early and late endosome markers, they become enriched in endosomal complex required for transport (ESCRT) proteins that are involved in MVB biogenesis. Further microscopy and viral replication analysis showed that functional ESCRT machinery is required for efficient Vf morphogenesis and production of infectious OROV particles. Taken together, our results indicate that OROV attracts ESCRT machinery components to Golgi cisternae to mediate membrane remodeling events required for viral assembly and budding at these compartments. This represents an unprecedented mechanism of how viruses hijack host cell components for coordinated morphogenesis.
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Abstract
In 2014, the world witnessed the largest Ebolavirus outbreak in recorded history. The subsequent humanitarian effort spurred extensive research, significantly enhancing our understanding of ebolavirus replication and pathogenicity. The main functions of each ebolavirus protein have been studied extensively since the discovery of the virus in 1976; however, the recent expansion of ebolavirus research has led to the discovery of new protein functions. These newly discovered roles are revealing new mechanisms of virus replication and pathogenicity, whilst enhancing our understanding of the broad functions of each ebolavirus viral protein (VP). Many of these new functions appear to be unrelated to the protein's primary function during virus replication. Such new functions range from bystander T-lymphocyte death caused by VP40-secreted exosomes to new roles for VP24 in viral particle formation. This review highlights the newly discovered roles of ebolavirus proteins in order to provide a more encompassing view of ebolavirus replication and pathogenicity.
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Affiliation(s)
- Diego Cantoni
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Jeremy S. Rossman
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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36
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Rumlová M, Ruml T. In vitro methods for testing antiviral drugs. Biotechnol Adv 2018; 36:557-576. [PMID: 29292156 PMCID: PMC7127693 DOI: 10.1016/j.biotechadv.2017.12.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/22/2017] [Accepted: 12/27/2017] [Indexed: 12/24/2022]
Abstract
Despite successful vaccination programs and effective treatments for some viral infections, humans are still losing the battle with viruses. Persisting human pandemics, emerging and re-emerging viruses, and evolution of drug-resistant strains impose continuous search for new antiviral drugs. A combination of detailed information about the molecular organization of viruses and progress in molecular biology and computer technologies has enabled rational antivirals design. Initial step in establishing efficacy of new antivirals is based on simple methods assessing inhibition of the intended target. We provide here an overview of biochemical and cell-based assays evaluating the activity of inhibitors of clinically important viruses.
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Affiliation(s)
- Michaela Rumlová
- Department of Biotechnology, University of Chemistry and Technology, Prague 166 28, Czech Republic.
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 166 28, Czech Republic.
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37
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Del Vecchio K, Frick CT, Gc JB, Oda SI, Gerstman BS, Saphire EO, Chapagain PP, Stahelin RV. A cationic, C-terminal patch and structural rearrangements in Ebola virus matrix VP40 protein control its interactions with phosphatidylserine. J Biol Chem 2018; 293:3335-3349. [PMID: 29348171 DOI: 10.1074/jbc.m117.816280] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/08/2018] [Indexed: 02/04/2023] Open
Abstract
Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes hemorrhagic fever with a high fatality rate. Viral protein 40 (VP40) is the major EBOV matrix protein and regulates viral budding from the plasma membrane. VP40 is a transformer/morpheein that can structurally rearrange its native homodimer into either a hexameric filament that facilitates viral budding or an RNA-binding octameric ring that regulates viral transcription. VP40 associates with plasma-membrane lipids such as phosphatidylserine (PS), and this association is critical to budding from the host cell. However, it is poorly understood how different VP40 structures interact with PS, what essential residues are involved in this association, and whether VP40 has true selectivity for PS among different glycerophospholipid headgroups. In this study, we used lipid-binding assays, MD simulations, and cellular imaging to investigate the molecular basis of VP40-PS interactions and to determine whether different VP40 structures (i.e. monomer, dimer, and octamer) can interact with PS-containing membranes. Results from quantitative analysis indicated that VP40 associates with PS vesicles via a cationic patch in the C-terminal domain (Lys224, 225 and Lys274, 275). Substitutions of these residues with alanine reduced PS-vesicle binding by >40-fold and abrogated VP40 localization to the plasma membrane. Dimeric VP40 had 2-fold greater affinity for PS-containing membranes than the monomer, whereas binding of the VP40 octameric ring was reduced by nearly 10-fold. Taken together, these results suggest the different VP40 structures known to form in the viral life cycle harbor different affinities for PS-containing membranes.
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Affiliation(s)
- Kathryn Del Vecchio
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Cary T Frick
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | | | | | | | - Erica Ollmann Saphire
- the Department of Immunology and Microbiology and.,The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, and
| | - Prem P Chapagain
- the Department of Physics and.,Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199
| | - Robert V Stahelin
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, .,the Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
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38
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Abstract
Independent expression of the VP40 or Z matrix proteins of filoviruses (marburgviruses and ebolaviruses) and arenaviruses (Lassa fever and Junín), respectively, gives rise to the production and release of virus-like particles (VLPs) that are morphologically identical to infectious virions. We can detect and quantify VLP production and egress in mammalian cells by transient transfection, SDS-PAGE, Western blotting, and live cell imaging techniques such as total internal reflection fluorescence (TIRF) microscopy. Since the VLP budding assay accurately mimics budding of infectious virus, this BSL-2 assay is safe and useful for the interrogation of both viral and host determinants required for budding and can be used as an initial screen to identify and validate small molecule inhibitors of virus release and spread.
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Affiliation(s)
- Ronald N Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA, 19104, USA.
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39
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Ubiquitin Ligase WWP1 Interacts with Ebola Virus VP40 To Regulate Egress. J Virol 2017; 91:JVI.00812-17. [PMID: 28768865 DOI: 10.1128/jvi.00812-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/24/2017] [Indexed: 01/05/2023] Open
Abstract
Ebola virus (EBOV) is a member of the Filoviridae family and the cause of hemorrhagic fever outbreaks. The EBOV VP40 (eVP40) matrix protein is the main driving force for virion assembly and budding. Indeed, expression of eVP40 alone in mammalian cells results in the formation and budding of virus-like particles (VLPs) which mimic the budding process and morphology of authentic, infectious EBOV. To complete the budding process, eVP40 utilizes its PPXY L-domain motif to recruit a specific subset of host proteins containing one or more modular WW domains that then function to facilitate efficient production and release of eVP40 VLPs. In this report, we identified additional host WW-domain interactors by screening for potential interactions between mammalian proteins possessing one or more WW domains and WT or PPXY mutant peptides of eVP40. We identified the HECT family E3 ubiquitin ligase WWP1 and all four of its WW domains as strong interactors with the PPXY motif of eVP40. The eVP40-WWP1 interaction was confirmed by both peptide pulldown and coimmunoprecipitation assays, which also demonstrated that modular WW domain 1 of WWP1 was most critical for binding to eVP40. Importantly, the eVP40-WWP1 interaction was found to be biologically relevant for VLP budding since (i) small interfering RNA (siRNA) knockdown of endogenous WWP1 resulted in inhibition of eVP40 VLP egress, (ii) coexpression of WWP1 and eVP40 resulted in ubiquitination of eVP40 and a subsequent increase in eVP40 VLP egress, and (iii) an enzymatically inactive mutant of WWP1 (C890A) did not ubiquitinate eVP40 or enhance eVP40 VLP egress. Last, our data show that ubiquitination of eVP40 by WWP1 enhances egress of VLPs and concomitantly decreases cellular levels of higher-molecular-weight oligomers of eVP40. In sum, these findings contribute to our fundamental understanding of the functional interplay between host E3 ligases, ubiquitination, and regulation of EBOV VP40-mediated egress.IMPORTANCE Ebola virus (EBOV) is a high-priority, emerging human pathogen that can cause severe outbreaks of hemorrhagic fever with high mortality rates. As there are currently no approved vaccines or treatments for EBOV, a better understanding of the biology and functions of EBOV-host interactions that promote or inhibit viral budding is warranted. Here, we describe a physical and functional interaction between EBOV VP40 (eVP40) and WWP1, a host E3 ubiquitin ligase that ubiquitinates VP40 and regulates VLP egress. This viral PPXY-host WW domain-mediated interaction represents a potential new target for host-oriented inhibitors of EBOV egress.
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Growing functions of the ESCRT machinery in cell biology and viral replication. Biochem Soc Trans 2017; 45:613-634. [PMID: 28620025 DOI: 10.1042/bst20160479] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/31/2023]
Abstract
The vast expansion in recent years of the cellular processes promoted by the endosomal sorting complex required for transport (ESCRT) machinery has reinforced its identity as a modular system that uses multiple adaptors to recruit the core membrane remodelling activity at different intracellular sites and facilitate membrane scission. Functional connections to processes such as the aurora B-dependent abscission checkpoint also highlight the importance of the spatiotemporal regulation of the ESCRT machinery. Here, we summarise the role of ESCRTs in viral budding, and what we have learned about the ESCRT pathway from studying this process. These advances are discussed in the context of areas of cell biology that have been transformed by research in the ESCRT field, including cytokinetic abscission, nuclear envelope resealing and plasma membrane repair.
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Pleet ML, DeMarino C, Lepene B, Aman MJ, Kashanchi F. The Role of Exosomal VP40 in Ebola Virus Disease. DNA Cell Biol 2017; 36:243-248. [PMID: 28177658 DOI: 10.1089/dna.2017.3639] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Ebola virus (EBOV) can cause a devastating hemorrhagic disease, leading to death in a short period of time. After infection, the resulting EBOV disease results in high levels of circulating cytokines, endothelial dysfunction, coagulopathy, and bystander lymphocyte apoptosis in humans and nonhuman primates. The VP40 matrix protein of EBOV is essential for viral assembly and budding from the host cell. Recent data have shown that VP40 exists in the extracellular environment, including in exosomes, and exosomal VP40 can impact the viability of recipient immune cells, including myeloid and T cells, through the regulation of the RNAi and endosomal sorting complexes required for transport pathways. In this study, we discuss the latest findings of the impact of exosomal VP40 on immune cells in vitro and its potential implications for pathogenesis in vivo.
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Affiliation(s)
- Michelle L Pleet
- 1 Laboratory of Molecular Virology, School of Systems Biology, George Mason University , Manassas, Virginia
| | - Catherine DeMarino
- 1 Laboratory of Molecular Virology, School of Systems Biology, George Mason University , Manassas, Virginia
| | | | - M Javad Aman
- 3 Integrated BioTherapeutics, Inc. , Gaithersburg, Maryland
| | - Fatah Kashanchi
- 1 Laboratory of Molecular Virology, School of Systems Biology, George Mason University , Manassas, Virginia
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Liang J, Sagum CA, Bedford MT, Sidhu SS, Sudol M, Han Z, Harty RN. Chaperone-Mediated Autophagy Protein BAG3 Negatively Regulates Ebola and Marburg VP40-Mediated Egress. PLoS Pathog 2017; 13:e1006132. [PMID: 28076420 PMCID: PMC5226679 DOI: 10.1371/journal.ppat.1006132] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 12/15/2016] [Indexed: 12/18/2022] Open
Abstract
Ebola (EBOV) and Marburg (MARV) viruses are members of the Filoviridae family which cause outbreaks of hemorrhagic fever. The filovirus VP40 matrix protein is essential for virus assembly and budding, and its PPxY L-domain motif interacts with WW-domains of specific host proteins, such as Nedd4 and ITCH, to facilitate the late stage of virus-cell separation. To identify additional WW-domain-bearing host proteins that interact with VP40, we used an EBOV PPxY-containing peptide to screen an array of 115 mammalian WW-domain-bearing proteins. Using this unbiased approach, we identified BCL2 Associated Athanogene 3 (BAG3), a member of the BAG family of molecular chaperone proteins, as a specific VP40 PPxY interactor. Here, we demonstrate that the WW-domain of BAG3 interacts with the PPxY motif of both EBOV and MARV VP40 and, unexpectedly, inhibits budding of both eVP40 and mVP40 virus-like particles (VLPs), as well as infectious VSV-EBOV recombinants. BAG3 is a stress induced protein that regulates cellular protein homeostasis and cell survival through chaperone-mediated autophagy (CMA). Interestingly, our results show that BAG3 alters the intracellular localization of VP40 by sequestering VP40 away from the plasma membrane. As BAG3 is the first WW-domain interactor identified that negatively regulates budding of VP40 VLPs and infectious virus, we propose that the chaperone-mediated autophagy function of BAG3 represents a specific host defense strategy to counteract the function of VP40 in promoting efficient egress and spread of virus particles.
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Affiliation(s)
- Jingjing Liang
- Department of Pathobiology, School Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
- Laboratory of Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
| | - Cari A. Sagum
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas Smithville, Smithville, TX, United States of America
| | - Mark T. Bedford
- Department of Epigenetics & Molecular Carcinogenesis, M.D. Anderson Cancer Center, University of Texas Smithville, Smithville, TX, United States of America
| | - Sachdev S. Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Marius Sudol
- Department of Physiology, National University of Singapore, Mechanobiology Institute and Institute for Molecular and Cell Biology (IMCB, A*STAR), Republic of Singapore
| | - Ziying Han
- Department of Pathobiology, School Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Ronald N. Harty
- Department of Pathobiology, School Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
- * E-mail:
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Groseth A, Hoenen T. Forty Years of Ebolavirus Molecular Biology: Understanding a Novel Disease Agent Through the Development and Application of New Technologies. Methods Mol Biol 2017; 1628:15-38. [PMID: 28573608 DOI: 10.1007/978-1-4939-7116-9_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Molecular biology is a broad discipline that seeks to understand biological phenomena at a molecular level, and achieves this through the study of DNA, RNA, proteins, and/or other macromolecules (e.g., those involved in the modification of these substrates). Consequently, it relies on the availability of a wide variety of methods that deal with the collection, preservation, inactivation, separation, manipulation, imaging, and analysis of these molecules. As such the state of the art in the field of ebolavirus molecular biology research (and that of all other viruses) is largely intertwined with, if not driven by, advancements in the technical methodologies available for these kinds of studies. Here we review of the current state of our knowledge regarding ebolavirus biology and emphasize the associated methods that made these discoveries possible.
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Affiliation(s)
- Allison Groseth
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Thomas Hoenen
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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Pleet ML, Mathiesen A, DeMarino C, Akpamagbo YA, Barclay RA, Schwab A, Iordanskiy S, Sampey GC, Lepene B, Nekhai S, Aman MJ, Kashanchi F. Ebola VP40 in Exosomes Can Cause Immune Cell Dysfunction. Front Microbiol 2016; 7:1765. [PMID: 27872619 PMCID: PMC5098130 DOI: 10.3389/fmicb.2016.01765] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/20/2016] [Indexed: 12/14/2022] Open
Abstract
Ebola virus (EBOV) is an enveloped, ssRNA virus from the family Filoviridae capable of causing severe hemorrhagic fever with up to 80–90% mortality rates. The most recent outbreak of EBOV in West Africa starting in 2014 resulted in over 11,300 deaths; however, long-lasting persistence and recurrence in survivors has been documented, potentially leading to further transmission of the virus. We have previously shown that exosomes from cells infected with HIV-1, HTLV-1 and Rift Valley Fever virus are able to transfer viral proteins and non-coding RNAs to naïve recipient cells, resulting in an altered cellular activity. In the current manuscript, we examined the effect of Ebola structural proteins VP40, GP, NP and VLPs on recipient immune cells, as well as the effect of exosomes containing these proteins on naïve immune cells. We found that VP40-transfected cells packaged VP40 into exosomes, and that these exosomes were capable of inducing apoptosis in recipient immune cells. Additionally, we show that presence of VP40 within parental cells or in exosomes delivered to naïve cells could result in the regulation of RNAi machinery including Dicer, Drosha, and Ago 1, which may play a role in the induction of cell death in recipient immune cells. Exosome biogenesis was regulated by VP40 in transfected cells by increasing levels of ESCRT-II proteins EAP20 and EAP45, and exosomal marker proteins CD63 and Alix. VP40 was phosphorylated by Cdk2/Cyclin complexes at Serine 233 which could be reversed with r-Roscovitine treatment. The level of VP40-containing exosomes could also be regulated by treated cells with FDA-approved Oxytetracycline. Additionally, we utilized novel nanoparticles to safely capture VP40 and other viral proteins from Ebola VLPs spiked into human samples using SDS/reducing agents, thus minimizing the need for BSL-4 conditions for most downstream assays. Collectively, our data indicates that VP40 packaged into exosomes may be responsible for the deregulation and eventual destruction of the T-cell and myeloid arms of the immune system (bystander lymphocyte apoptosis), allowing the virus to replicate to high titers in the immunocompromised host. Moreover, our results suggest that the use of drugs such as Oxytetracycline to modulate the levels of exosomes exiting EBOV-infected cells may be able to prevent the devastation of the adaptive immune system and allow for an improved rate of survival.
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Affiliation(s)
- Michelle L Pleet
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
| | - Allison Mathiesen
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk VA, USA
| | - Catherine DeMarino
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
| | - Yao A Akpamagbo
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
| | - Robert A Barclay
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
| | - Angela Schwab
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
| | - Sergey Iordanskiy
- Research Center for Neglected Diseases of Poverty, Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington DC, USA
| | - Gavin C Sampey
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, ManassasVA, USA; University of North Carolina HIV Cure Center, Department of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel HillNC, USA
| | | | - Sergei Nekhai
- Center for Sickle Cell Disease, Department of Medicine, Howard University, Washington DC, USA
| | - M J Aman
- Integrated BioTherapeutics, Inc., Gaithersburg MD, USA
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas VA, USA
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ITCH E3 Ubiquitin Ligase Interacts with Ebola Virus VP40 To Regulate Budding. J Virol 2016; 90:9163-71. [PMID: 27489272 DOI: 10.1128/jvi.01078-16] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/25/2016] [Indexed: 01/27/2023] Open
Abstract
UNLABELLED Ebola virus (EBOV) and Marburg virus (MARV) belong to the Filoviridae family and can cause outbreaks of severe hemorrhagic fever, with high mortality rates in humans. The EBOV VP40 (eVP40) and MARV VP40 (mVP40) matrix proteins play a central role in virion assembly and egress, such that independent expression of VP40 leads to the production and egress of virus-like particles (VLPs) that accurately mimic the budding of infectious virus. Late (L) budding domains of eVP40 recruit host proteins (e.g., Tsg101, Nedd4, and Alix) that are important for efficient virus egress and spread. For example, the PPxY-type L domain of eVP40 and mVP40 recruits the host Nedd4 E3 ubiquitin ligase via its WW domains to facilitate budding. Here we sought to identify additional WW domain host interactors and demonstrate that the PPxY L domain motif of eVP40 interacts specifically with the WW domain of the host E3 ubiquitin ligase ITCH. ITCH, like Nedd4, is a member of the HECT class of E3 ubiquitin ligases, and the resultant physical and functional interaction with eVP40 facilitates VLP and virus budding. Identification of this novel eVP40 interactor highlights the functional interplay between cellular E3 ligases, ubiquitination, and regulation of VP40-mediated egress. IMPORTANCE The unprecedented magnitude and scope of the recent 2014-2015 EBOV outbreak in West Africa and its emergence here in the United States and other countries underscore the critical need for a better understanding of the biology and pathogenesis of this emerging pathogen. We have identified a novel and functional EBOV VP40 interactor, ITCH, that regulates VP40-mediated egress. This virus-host interaction may represent a new target for our previously identified small-molecule inhibitors of virus egress.
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Affiliation(s)
- Angela L. Rasmussen
- Department of Microbiology, University of Washington, Seattle, Washington 98109;
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Abstract
Viruses have evolved many mechanisms by which to evade and subvert the immune system to ensure survival and persistence. However, for each method undertaken by the immune system for pathogen removal, there is a counteracting mechanism utilized by pathogens. The new and emerging role of microvesicles in immune intercellular communication and function is no different. Viruses across many different families have evolved to insert viral components in exosomes, a subtype of microvesicle, with many varying downstream effects. When assessed cumulatively, viral antigens in exosomes increase persistence through cloaking viral genomes, decoying the immune system, and even by increasing viral infection in uninfected cells. Exosomes therefore represent a source of viral antigen that can be used as a biomarker for disease and targeted for therapy in the control and eradication of these disorders. With the rise in the persistence of new and reemerging viruses like Ebola and Zika, exploring the role of exosomes become more important than ever.
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Affiliation(s)
- Monique R Anderson
- National Institutes of Health, National Institute of Neurological Disorders and Stroke, Neuroimmunology Branch, Viral Immunology Section, Bethesda, MD, 20892, USA.
- Department of Pathology Molecular and Cellular Basis of Disease Graduate Program, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.
| | - Fatah Kashanchi
- George Mason University, National Center for Biodefense and Infectious Disease, Laboratory of Molecular Virology, Manassas, VA, 20110, USA
| | - Steven Jacobson
- National Institutes of Health, National Institute of Neurological Disorders and Stroke, Neuroimmunology Branch, Viral Immunology Section, Bethesda, MD, 20892, USA
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Freedman BD, Harty RN. Calcium and filoviruses: a budding relationship. Future Microbiol 2016; 11:713-5. [DOI: 10.2217/fmb-2016-0057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Bruce D Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St, Philadelphia, PA 19104, USA
| | - Ronald N Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St, Philadelphia, PA 19104, USA
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Sobhy H. A Review of Functional Motifs Utilized by Viruses. Proteomes 2016; 4:proteomes4010003. [PMID: 28248213 PMCID: PMC5217368 DOI: 10.3390/proteomes4010003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/07/2016] [Accepted: 01/13/2016] [Indexed: 01/05/2023] Open
Abstract
Short linear motifs (SLiM) are short peptides that facilitate protein function and protein-protein interactions. Viruses utilize these motifs to enter into the host, interact with cellular proteins, or egress from host cells. Studying functional motifs may help to predict protein characteristics, interactions, or the putative cellular role of a protein. In virology, it may reveal aspects of the virus tropism and help find antiviral therapeutics. This review highlights the recent understanding of functional motifs utilized by viruses. Special attention was paid to the function of proteins harboring these motifs, and viruses encoding these proteins. The review highlights motifs involved in (i) immune response and post-translational modifications (e.g., ubiquitylation, SUMOylation or ISGylation); (ii) virus-host cell interactions, including virus attachment, entry, fusion, egress and nuclear trafficking; (iii) virulence and antiviral activities; (iv) virion structure; and (v) low-complexity regions (LCRs) or motifs enriched with residues (Xaa-rich motifs).
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Affiliation(s)
- Haitham Sobhy
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.
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