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Romanov KA, O'Connor TJ. Legionella pneumophila, a Rosetta stone to understanding bacterial pathogenesis. J Bacteriol 2024; 206:e0032424. [PMID: 39636264 DOI: 10.1128/jb.00324-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2024] Open
Abstract
Legionella pneumophila is an environmentally acquired pathogen that causes respiratory disease in humans. While the discovery of L. pneumophila is relatively recent compared to other bacterial pathogens, over the past 50 years, L. pneumophila has emerged as a powerhouse for studying host-pathogen interactions. In its natural habitat of fresh water, L. pneumophila interacts with a diverse array of protozoan hosts and readily evolve to expand their host range. This has led to the accumulation of the most extensive arsenal of secreted virulence factors described for a bacterial pathogen and their ability to infect humans. Within amoebae and human alveolar macrophages, the bacteria replicate within specialized membrane-bound compartments, establishing L. pneumophila as a model for studying intracellular vacuolar pathogens. In contrast, the virulence factors required for intracellular replication are specifically tailored to individual host cells types, allowing the pathogen to adapt to variation between disparate niches. The broad host range of this pathogen, combined with the extensive diversity and genome plasticity across the Legionella genus, has thus established this bacterium as an archetype to interrogate pathogen evolution, functional genomics, and ecology. In this review, we highlight the features of Legionella that establish them as a versatile model organism, new paradigms in bacteriology and bacterial pathogenesis resulting from the study of Legionella, as well as current and future questions that will undoubtedly expand our understanding of the complex and intricate biology of the microbial world.
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Affiliation(s)
- Katerina A Romanov
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tamara J O'Connor
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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2
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Nagy PD, Pogany J, Kang Y. Novel exploitation of autophagy by tombusviruses. Virology 2024; 603:110363. [PMID: 39708618 DOI: 10.1016/j.virol.2024.110363] [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: 10/23/2024] [Revised: 12/04/2024] [Accepted: 12/16/2024] [Indexed: 12/23/2024]
Abstract
Positive-strand (+)RNA viruses are major pathogens of humans, animals and plants. This review summarizes the complex interplay between the host autophagy pathway and Tomato bushy stunt virus (TBSV) replication. Recent discoveries with TBSV have revealed virus-driven exploitation of autophagy in multiple ways that contributes to the unique phospholipid composition of viral replication organellar (VROs) membranes. Viral replication protein-driven subversion of phagophore membranes, recruitment of ATG2 bulk lipid transfer protein to enrich phosphatidylethanolamine and phosphatidylserine in VROs, recruitment of VPS34 PI3K to produce PI(3)P; and ATG11-facilitated formation of stable viral membrane contact sites contributes to VRO membrane proliferation. Recruitment of autophagy core proteins to vir-NBR1 bodies within vir-condensates associated with VROs results in dampened antiviral degradation by autophagy. Overall, TBSV intricate interplay with the autophagy machinery highlights the importance of lipid dynamics in viral life cycles and points toward potential directions for therapeutic intervention.
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Affiliation(s)
- Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA.
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA
| | - Yuanrong Kang
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA
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3
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Sánchez‐López CM, Soler C, Garzo E, Fereres A, Pérez‐Bermúdez P, Marcilla A. Phloem sap from melon plants contains extracellular vesicles that carry active proteasomes which increase in response to aphid infestation. J Extracell Vesicles 2024; 13:e12517. [PMID: 39385682 PMCID: PMC11464910 DOI: 10.1002/jev2.12517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 08/09/2024] [Accepted: 09/04/2024] [Indexed: 10/12/2024] Open
Abstract
The morphogenesis of higher plants requires communication among distant organs throughout vascular tissues (xylem and phloem). Numerous investigations have demonstrated that phloem also act as a distribution route for signalling molecules being observed that different macromolecules translocated by the sap, including nucleic acids and proteins, change under stress situations. The participation of extracellular vesicles (EVs) in this communication has been suggested, although little is known about their role. In fact, in the last decade, the presence of EVs in plants has originated a great controversy, where major concerns arose from their origin, isolation methods, and even the appropriate nomenclature for plant nanovesicles. Phloem sap exudates from melon plants, either aphid-free or infested with Aphis gossypii, were collected by stem incision. After sap concentration (Amicon), phloem EVs (PhlEVs) were isolated by size exclusion chromatography. PhlEVs were characterised using Nanoparticle Tracking Analysis, Transmission electron microscopy and proteomic analysis. Here we confirm the presence of EVs in phloem sap in vivo and the detection of changes in the particles/protein ratio and composition of PhlEVs in response to insect feeding, revealing the presence of typical defence proteins in their cargo as well as components of the proteasome complex. PhlEVs from infested plants showed lower particles/protein ratio and almost two times more proteolytic activity than PhlEVs from aphid-free plants. In both cases, such activity was inhibited in a dose-dependent manner by the proteasome inhibitor MG132. Our results suggest that plants may use this mechanism to prepare themselves to receive infectious agents and open up the possibility of an evolutionary conserved mechanism of defence against pathogens/stresses in eukaryotic organisms.
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Affiliation(s)
- Christian M. Sánchez‐López
- Área de Parasitología, Dept. Farmacia y Tecnología Farmacéutica y Parasitología, F. FarmàciaUniversitat de ValènciaBurjassotValenciaSpain
- Joint Unit on Endocrinology, Nutrition and Clinical DieteticsIIS La Fe‐Universitat de ValènciaValenciaSpain
| | - Carla Soler
- Joint Unit on Endocrinology, Nutrition and Clinical DieteticsIIS La Fe‐Universitat de ValènciaValenciaSpain
- Instituto de Ciencia de los Materiales, Parque CientíficoUniversitat de ValènciaBurjassotValenciaSpain
| | - Elisa Garzo
- Instituto de Ciencias AgrariasICA‐CSICMadridSpain
| | | | - Pedro Pérez‐Bermúdez
- Dept. Biologia Vegetal, F. Ciències BiológiquesUniversitat de ValènciaBurjassotValenciaSpain
| | - Antonio Marcilla
- Área de Parasitología, Dept. Farmacia y Tecnología Farmacéutica y Parasitología, F. FarmàciaUniversitat de ValènciaBurjassotValenciaSpain
- Joint Unit on Endocrinology, Nutrition and Clinical DieteticsIIS La Fe‐Universitat de ValènciaValenciaSpain
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Lin W, Nagy PD. Co-opted cytosolic proteins form condensate substructures within membranous replication organelles of a positive-strand RNA virus. THE NEW PHYTOLOGIST 2024; 243:1917-1935. [PMID: 38515267 DOI: 10.1111/nph.19691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/22/2024] [Indexed: 03/23/2024]
Abstract
Positive-strand RNA viruses co-opt organellar membranes for biogenesis of viral replication organelles (VROs). Tombusviruses also co-opt pro-viral cytosolic proteins to VROs. It is currently not known what type of molecular organization keeps co-opted proteins sequestered within membranous VROs. In this study, we employed tomato bushy stunt virus (TBSV) and carnation Italian ringspot virus (CIRV) - Nicotiana benthamiana pathosystems to identify biomolecular condensate formation in VROs. We show that TBSV p33 and the CIRV p36 replication proteins sequester glycolytic and fermentation enzymes in unique condensate substructures associated with membranous VROs. We find that p33 and p36 form droplets in vitro driven by intrinsically disordered region. The replication protein organizes partitioning of co-opted host proteins into droplets. VRO-associated condensates are critical for local adenosine triphosphate production to support energy for virus replication. We find that co-opted endoplasmic reticulum membranes and actin filaments form meshworks within and around VRO condensates, contributing to unique composition and structure. We propose that p33/p36 organize liquid-liquid phase separation of co-opted concentrated host proteins in condensate substructures within membranous VROs. Overall, we demonstrate that subverted membranes and condensate substructures co-exist and are critical for VRO functions. The replication proteins induce and connect the two substructures within VROs.
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Affiliation(s)
- Wenwu Lin
- Department of Plant Pathology, University of Kentucky, Lexington, KY, 40543, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, KY, 40543, USA
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He R, Li Y, Bernards MA, Wang A. Manipulation of the Cellular Membrane-Cytoskeleton Network for RNA Virus Replication and Movement in Plants. Viruses 2023; 15:744. [PMID: 36992453 PMCID: PMC10056259 DOI: 10.3390/v15030744] [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: 02/01/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/15/2023] Open
Abstract
Viruses infect all cellular life forms and cause various diseases and significant economic losses worldwide. The majority of viruses are positive-sense RNA viruses. A common feature of infection by diverse RNA viruses is to induce the formation of altered membrane structures in infected host cells. Indeed, upon entry into host cells, plant-infecting RNA viruses target preferred organelles of the cellular endomembrane system and remodel organellar membranes to form organelle-like structures for virus genome replication, termed as the viral replication organelle (VRO) or the viral replication complex (VRC). Different viruses may recruit different host factors for membrane modifications. These membrane-enclosed virus-induced replication factories provide an optimum, protective microenvironment to concentrate viral and host components for robust viral replication. Although different viruses prefer specific organelles to build VROs, at least some of them have the ability to exploit alternative organellar membranes for replication. Besides being responsible for viral replication, VROs of some viruses can be mobile to reach plasmodesmata (PD) via the endomembrane system, as well as the cytoskeleton machinery. Viral movement protein (MP) and/or MP-associated viral movement complexes also exploit the endomembrane-cytoskeleton network for trafficking to PD where progeny viruses pass through the cell-wall barrier to enter neighboring cells.
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Affiliation(s)
- Rongrong He
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Yinzi Li
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
| | - Mark A. Bernards
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Aiming Wang
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
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Feng Z, Kovalev N, Nagy PD. Multifunctional role of the co-opted Cdc48 AAA+ ATPase in tombusvirus replication. Virology 2022; 576:1-17. [PMID: 36126429 DOI: 10.1016/j.virol.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/07/2022] [Indexed: 10/31/2022]
Abstract
Replication of positive-strand RNA viruses depends on usurped cellular membranes and co-opted host proteins. Based on pharmacological inhibition and genetic and biochemical approaches, the authors identified critical roles of the cellular Cdc48 unfoldase/segregase protein in facilitating the replication of tomato bushy stunt virus (TBSV). We show that TBSV infection induces the expression of Cdc48 in Nicotiana benthamiana plants. Cdc48 binds to the TBSV replication proteins through its N-terminal region. In vitro TBSV replicase reconstitution experiments demonstrated that Cdc48 is needed for efficient replicase assembly and activity. Surprisingly, the in vitro replication experiments also showed that excess amount of Cdc48 facilitates the disassembly of the membrane-bound viral replicase-RNA template complex. Cdc48 is also needed for the recruitment of additional host proteins. Because several human viruses, including flaviviruses, utilize Cdc48, also called VCP/p97, for replication, we suggest that Cdc48 might be a common panviral host factor for plant and animal RNA viruses.
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Affiliation(s)
- Zhike Feng
- Department of Plant Pathology, University of Kentucky, Lexington, USA
| | - Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, USA.
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Race against Time between the Virus and Host: Actin-Assisted Rapid Biogenesis of Replication Organelles is Used by TBSV to Limit the Recruitment of Cellular Restriction Factors. J Virol 2022; 96:e0016821. [PMID: 35638821 DOI: 10.1128/jvi.00168-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Positive-strand RNA viruses build large viral replication organelles (VROs) with the help of coopted host factors. Previous works on tomato bushy stunt virus (TBSV) showed that the p33 replication protein subverts the actin cytoskeleton by sequestering the actin depolymerization factor, cofilin, to reduce actin filament disassembly and stabilize the actin filaments. Then, TBSV utilizes the stable actin filaments as "trafficking highways" to deliver proviral host factors into the protective VROs. In this work, we show that the cellular intrinsic restriction factors (CIRFs) also use the actin network to reach VROs and inhibit viral replication. Disruption of the actin filaments by expression of the Legionella RavK protease inhibited the recruitment of plant CIRFs, including the CypA-like Roc1 and Roc2 cyclophilins, and the antiviral DDX17-like RH30 DEAD box helicase into VROs. Conversely, temperature-sensitive actin and cofilin mutant yeasts with stabilized actin filaments reduced the levels of copurified CIRFs, including cyclophilins Cpr1, CypA, Cyp40-like Cpr7, cochaperones Sgt2, the Hop-like Sti1, and the RH30 helicase in viral replicase preparations. Dependence of the recruitment of both proviral and antiviral host factors into VROs on the actin network suggests that there is a race going on between TBSV and its host to exploit the actin network and ultimately to gain the upper hand during infection. We propose that, in the highly susceptible plants, tombusviruses efficiently subvert the actin network for rapid delivery of proviral host factors into VROs and ultimately overcome host restriction factors via winning the recruitment race and overwhelming cellular defenses. IMPORTANCE Replication of positive-strand RNA viruses is affected by the recruitment of host components, which provide either proviral or antiviral functions during virus invasion of infected cells. The delivery of these host factors into the viral replication organelles (VROs), which represent the sites of viral RNA replication, depends on the cellular actin network. Using TBSV, we uncover a race between the virus and its host with the actin network as the central player. We find that in susceptible plants, tombusviruses exploit the actin network for rapid delivery of proviral host factors into VROs and ultimately overcome host restriction factors. In summary, this work demonstrates that the actin network plays a major role in determining the outcome of viral infections in plants.
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Wang H, Cui X, Cai X, An T. Recombination in Positive-Strand RNA Viruses. Front Microbiol 2022; 13:870759. [PMID: 35663855 PMCID: PMC9158499 DOI: 10.3389/fmicb.2022.870759] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/21/2022] [Indexed: 12/28/2022] Open
Abstract
RNA recombination is a major driver of genetic shifts tightly linked to the evolution of RNA viruses. Genomic recombination contributes substantially to the emergence of new viral lineages, expansion in host tropism, adaptations to new environments, and virulence and pathogenesis. Here, we review some of the recent progress that has advanced our understanding of recombination in positive-strand RNA viruses, including recombination triggers and the mechanisms behind them. The study of RNA recombination aids in predicting the probability and outcome of viral recombination events, and in the design of viruses with reduced recombination frequency as candidates for the development of live attenuated vaccines. Surveillance of viral recombination should remain a priority in the detection of emergent viral strains, a goal that can only be accomplished by expanding our understanding of how these events are triggered and regulated.
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Affiliation(s)
| | | | | | - Tongqing An
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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Kang Y, Lin W, Liu Y, Nagy PD. Key tethering function of Atg11 autophagy scaffold protein in formation of virus-induced membrane contact sites during tombusvirus replication. Virology 2022; 572:1-16. [DOI: 10.1016/j.virol.2022.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 01/04/2023]
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