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Lockwood DC, Amin H, Costa TRD, Schroeder GN. The Legionella pneumophila Dot/Icm type IV secretion system and its effectors. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35639581 DOI: 10.1099/mic.0.001187] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To prevail in the interaction with eukaryotic hosts, many bacterial pathogens use protein secretion systems to release virulence factors at the host–pathogen interface and/or deliver them directly into host cells. An outstanding example of the complexity and sophistication of secretion systems and the diversity of their protein substrates, effectors, is the Defective in organelle trafficking/Intracellular multiplication (Dot/Icm) Type IVB secretion system (T4BSS) of
Legionella pneumophila
and related species.
Legionella
species are facultative intracellular pathogens of environmental protozoa and opportunistic human respiratory pathogens. The Dot/Icm T4BSS translocates an exceptionally large number of effectors, more than 300 per
L. pneumophila
strain, and is essential for evasion of phagolysosomal degradation and exploitation of protozoa and human macrophages as replicative niches. Recent technological advancements in the imaging of large protein complexes have provided new insight into the architecture of the T4BSS and allowed us to propose models for the transport mechanism. At the same time, significant progress has been made in assigning functions to about a third of
L. pneumophila
effectors, discovering unprecedented new enzymatic activities and concepts of host subversion. In this review, we describe the current knowledge of the workings of the Dot/Icm T4BSS machinery and provide an overview of the activities and functions of the to-date characterized effectors in the interaction of
L. pneumophila
with host cells.
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Affiliation(s)
- Daniel C Lockwood
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
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2
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Ge Z, Yuan P, Chen L, Chen J, Shen D, She Z, Lu Y. New Global Insights on the Regulation of the Biphasic Life Cycle and Virulence Via ClpP-Dependent Proteolysis in Legionella pneumophila. Mol Cell Proteomics 2022; 21:100233. [PMID: 35427813 PMCID: PMC9112007 DOI: 10.1016/j.mcpro.2022.100233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 02/17/2022] [Accepted: 04/07/2022] [Indexed: 01/11/2023] Open
Abstract
Legionella pneumophila, an environmental bacterium that parasitizes protozoa, causes Legionnaires’ disease in humans that is characterized by severe pneumonia. This bacterium adopts a distinct biphasic life cycle consisting of a nonvirulent replicative phase and a virulent transmissive phase in response to different environmental conditions. Hence, the timely and fine-tuned expression of growth and virulence factors in a life cycle–dependent manner is crucial for survival and replication. Here, we report that the completion of the biphasic life cycle and bacterial pathogenesis is greatly dependent on the protein homeostasis regulated by caseinolytic protease P (ClpP)-dependent proteolysis. We characterized the ClpP-dependent dynamic profiles of the regulatory and substrate proteins during the biphasic life cycle of L. pneumophila using proteomic approaches and discovered that ClpP-dependent proteolysis specifically and conditionally degraded the substrate proteins, thereby directly playing a regulatory role or indirectly controlling cellular events via the regulatory proteins. We further observed that ClpP-dependent proteolysis is required to monitor the abundance of fatty acid biosynthesis–related protein Lpg0102/Lpg0361/Lpg0362 and SpoT for the normal regulation of L. pneumophila differentiation. We also found that the control of the biphasic life cycle and bacterial virulence is independent. Furthermore, the ClpP-dependent proteolysis of Dot/Icm (defect in organelle trafficking/intracellular multiplication) type IVB secretion system and effector proteins at a specific phase of the life cycle is essential for bacterial pathogenesis. Therefore, our findings provide novel insights on ClpP-dependent proteolysis, which spans a broad physiological spectrum involving key metabolic pathways that regulate the transition of the biphasic life cycle and bacterial virulence of L. pneumophila, facilitating adaptation to aquatic and intracellular niches. ClpP is the major determinant of biphasic life cycle–dependent protein turnover. ClpP-dependent proteolysis monitors SpoT abundance for cellular differentiation. ClpP-dependent regulation of life cycle and bacterial virulence is independent. ClpP-dependent proteolysis of T4BSS and effector proteins is vital for virulence.
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Affiliation(s)
- Zhenhuang Ge
- School of Chemistry, Sun Yat-sen University, Guangzhou, China; School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou, China
| | - Peibo Yuan
- Microbiome Medicine Center, Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Lingming Chen
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Junyi Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou, China
| | - Dong Shen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhigang She
- School of Chemistry, Sun Yat-sen University, Guangzhou, China
| | - Yongjun Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Run Ze Laboratory for Gastrointestinal Microbiome Study, Sun Yat-sen University, Guangzhou, China.
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3
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Belyi Y, Levanova N, Schroeder GN. Glycosylating Effectors of Legionella pneumophila: Finding the Sweet Spots for Host Cell Subversion. Biomolecules 2022; 12:255. [PMID: 35204756 PMCID: PMC8961657 DOI: 10.3390/biom12020255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 02/04/2023] Open
Abstract
Work over the past two decades clearly defined a significant role of glycosyltransferase effectors in the infection strategy of the Gram-negative, respiratory pathogen Legionella pneumophila. Identification of the glucosyltransferase effectors Lgt1-3, specifically modifying elongation factor eEF1A, disclosed a novel mechanism of host protein synthesis manipulation by pathogens and illuminated its impact on the physiological state of the target cell, in particular cell cycle progression and immune and stress responses. Recent characterization of SetA as a general O-glucosyltransferase with a wide range of targets including the proteins Rab1 and Snx1, mediators of membrane transport processes, and the discovery of new types of glycosyltransferases such as LtpM and SidI indicate that the vast effector arsenal might still hold more so-far unrecognized family members with new catalytic features and substrates. In this article, we review our current knowledge regarding these fascinating biomolecules and discuss their role in introducing new or overriding endogenous post-translational regulatory mechanisms enabling the subversion of eukaryotic cells by L. pneumophila.
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Affiliation(s)
- Yury Belyi
- Laboratory of Molecular Pathogenesis, Gamaleya Research Centre, 123098 Moscow, Russia
| | | | - Gunnar N. Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK
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4
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Taujale R, Zhou Z, Yeung W, Moremen KW, Li S, Kannan N. Mapping the glycosyltransferase fold landscape using interpretable deep learning. Nat Commun 2021; 12:5656. [PMID: 34580305 PMCID: PMC8476585 DOI: 10.1038/s41467-021-25975-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/31/2021] [Indexed: 12/28/2022] Open
Abstract
Glycosyltransferases (GTs) play fundamental roles in nearly all cellular processes through the biosynthesis of complex carbohydrates and glycosylation of diverse protein and small molecule substrates. The extensive structural and functional diversification of GTs presents a major challenge in mapping the relationships connecting sequence, structure, fold and function using traditional bioinformatics approaches. Here, we present a convolutional neural network with attention (CNN-attention) based deep learning model that leverages simple secondary structure representations generated from primary sequences to provide GT fold prediction with high accuracy. The model learns distinguishing secondary structure features free of primary sequence alignment constraints and is highly interpretable. It delineates sequence and structural features characteristic of individual fold types, while classifying them into distinct clusters that group evolutionarily divergent families based on shared secondary structural features. We further extend our model to classify GT families of unknown folds and variants of known folds. By identifying families that are likely to adopt novel folds such as GT91, GT96 and GT97, our studies expand the GT fold landscape and prioritize targets for future structural studies.
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Affiliation(s)
- Rahil Taujale
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Zhongliang Zhou
- Department of Computer Science, University of Georgia, Athens, GA, USA
| | - Wayland Yeung
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Sheng Li
- Department of Computer Science, University of Georgia, Athens, GA, USA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA.
- Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
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5
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Striednig B, Lanner U, Niggli S, Katic A, Vormittag S, Brülisauer S, Hochstrasser R, Kaech A, Welin A, Flieger A, Ziegler U, Schmidt A, Hilbi H, Personnic N. Quorum sensing governs a transmissive Legionella subpopulation at the pathogen vacuole periphery. EMBO Rep 2021; 22:e52972. [PMID: 34314090 PMCID: PMC8419707 DOI: 10.15252/embr.202152972] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/01/2021] [Accepted: 07/08/2021] [Indexed: 01/24/2023] Open
Abstract
The Gram‐negative bacterium Legionella pneumophila is the causative agent of Legionnaires' disease and replicates in amoebae and macrophages within a distinct compartment, the Legionella‐containing vacuole (LCV). The facultative intracellular pathogen switches between a replicative, non‐virulent and a non‐replicating, virulent/transmissive phase. Here, we show on a single‐cell level that at late stages of infection, individual motile (PflaA‐GFP‐positive) and virulent (PralF‐ and PsidC‐GFP‐positive) L. pneumophila emerge in the cluster of non‐growing bacteria within an LCV. Comparative proteomics of PflaA‐GFP‐positive and PflaA‐GFP‐negative L. pneumophila subpopulations reveals distinct proteomes with flagellar proteins or cell division proteins being preferentially produced by the former or the latter, respectively. Toward the end of an infection cycle (˜ 48 h), the PflaA‐GFP‐positive L. pneumophila subpopulation emerges at the cluster periphery, predominantly escapes the LCV, and spreads from the bursting host cell. These processes are mediated by the Legionella quorum sensing (Lqs) system. Thus, quorum sensing regulates the emergence of a subpopulation of transmissive L. pneumophila at the LCV periphery, and phenotypic heterogeneity underlies the intravacuolar bi‐phasic life cycle of L. pneumophila.
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Affiliation(s)
- Bianca Striednig
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Ulrike Lanner
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Selina Niggli
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Ana Katic
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Simone Vormittag
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Sabrina Brülisauer
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Ramon Hochstrasser
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zürich, Zürich, Switzerland
| | - Amanda Welin
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zürich, Zürich, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Nicolas Personnic
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
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Ramirez-Mondragon CA, Nguyen ME, Milicaj J, Hassan BA, Tucci FJ, Muthyala R, Gao J, Taylor EA, Sham YY. Conserved Conformational Hierarchy across Functionally Divergent Glycosyltransferases of the GT-B Structural Superfamily as Determined from Microsecond Molecular Dynamics. Int J Mol Sci 2021; 22:ijms22094619. [PMID: 33924837 PMCID: PMC8124905 DOI: 10.3390/ijms22094619] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 11/19/2022] Open
Abstract
It has long been understood that some proteins undergo conformational transitions en route to the Michaelis Complex to allow chemistry. Examination of crystal structures of glycosyltransferase enzymes in the GT-B structural class reveals that the presence of ligand in the active site triggers an open-to-closed conformation transition, necessary for their catalytic functions. Herein, we describe microsecond molecular dynamics simulations of two distantly related glycosyltransferases that are part of the GT-B structural superfamily, HepI and GtfA. Simulations were performed using the open and closed conformations of these unbound proteins, respectively, and we sought to identify the major dynamical modes and communication networks that interconnect the open and closed structures. We provide the first reported evidence within the scope of our simulation parameters that the interconversion between open and closed conformations is a hierarchical multistep process which can be a conserved feature of enzymes of the same structural superfamily. Each of these motions involves of a collection of smaller molecular reorientations distributed across both domains, highlighting the complexities of protein dynamic involved in the interconversion process. Additionally, dynamic cross-correlation analysis was employed to explore the potential effect of distal residues on the catalytic efficiency of HepI. Multiple distal nonionizable residues of the C-terminal domain exhibit motions anticorrelated to positively charged residues in the active site in the N-terminal domain involved in substrate binding. Mutations of these residues resulted in a reduction in negatively correlated motions and an altered enzymatic efficiency that is dominated by lower Km values with kcat effectively unchanged. The findings suggest that residues with opposing conformational motions involved in the opening and closing of the bidomain HepI protein can allosterically alter the population and conformation of the “closed” state, essential to the formation of the Michaelis complex. The stabilization effects of these mutations likely equally influence the energetics of both the ground state and the transition state of the catalytic reaction, leading to the unaltered kcat. Our study provides new insights into the role of conformational dynamics in glycosyltransferase’s function and new modality to modulate enzymatic efficiency.
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Affiliation(s)
- Carlos A. Ramirez-Mondragon
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA; (C.A.R.-M.); (M.E.N.); (J.G.)
| | - Megin E. Nguyen
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA; (C.A.R.-M.); (M.E.N.); (J.G.)
| | - Jozafina Milicaj
- Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA; (J.M.); (B.A.H.); (F.J.T.)
| | - Bakar A. Hassan
- Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA; (J.M.); (B.A.H.); (F.J.T.)
| | - Frank J. Tucci
- Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA; (J.M.); (B.A.H.); (F.J.T.)
| | - Ramaiah Muthyala
- Department of Experimental and Clinical Pharmacology, College Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Jiali Gao
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA; (C.A.R.-M.); (M.E.N.); (J.G.)
- Department of Chemistry, University of Minnesota, Minneapolis, Minneapolis, MN 55455, USA
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Erika A. Taylor
- Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA; (J.M.); (B.A.H.); (F.J.T.)
- Correspondence: (E.A.T.); (Y.Y.S.); Tel.: +1-(860)-685-2739 (E.A.T.); +1-(612)-625-6255 (Y.Y.S.); Fax: +1-(860)-685-2211 (E.A.T.); +1-(612)-625-5149 (Y.Y.S.)
| | - Yuk Y. Sham
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA; (C.A.R.-M.); (M.E.N.); (J.G.)
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: (E.A.T.); (Y.Y.S.); Tel.: +1-(860)-685-2739 (E.A.T.); +1-(612)-625-6255 (Y.Y.S.); Fax: +1-(860)-685-2211 (E.A.T.); +1-(612)-625-5149 (Y.Y.S.)
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7
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Koh E, Cho HS. NleB/SseKs ortholog effectors as a general bacterial monoglycosyltransferase for eukaryotic proteins. Curr Opin Struct Biol 2021; 68:215-223. [PMID: 33761453 DOI: 10.1016/j.sbi.2021.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/20/2022]
Abstract
Protein glycosylation is the most common post-translational modification as more than 50% of all human proteins are glycosylated. Pathogenic bacteria glycosylation allows adhesion to host cells and manipulates eukaryotic functions. A variety of acceptor proteins in bacterial glycosylation was recently discovered. Especially NleB/SseKs type III effectors unexpectedly glycosylate a poor nucleophile arginine. Other pathogenic toxins modify the unusual tyrosine, as well as canonical serine/threonine residues. And a huge diversity is found in target proteins; Rho/Ras families, death domains and moreover themselves for autoglycosylation. However, in spite of this acceptor diversity, all their sugar donors are only UDP-Glc/-GlcNAc and structural alignments as liganded show their catalytic cores are geometrically conserved, where DRY and DXD motives and W residues equally position to hold the sugar donors and to π-π bind with a uridine ring, respectively. Therefore, bacterial glycosyltransferases have a key for carbohydrate research problems concerning the sugar donors and target proteins recognition.
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Affiliation(s)
- Eunhee Koh
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea.
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8
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Kovalev N, Pogany J, Nagy PD. Reconstitution of an RNA Virus Replicase in Artificial Giant Unilamellar Vesicles Supports Full Replication and Provides Protection for the Double-Stranded RNA Replication Intermediate. J Virol 2020; 94:e00267-20. [PMID: 32641477 PMCID: PMC7459549 DOI: 10.1128/jvi.00267-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/29/2020] [Indexed: 01/23/2023] Open
Abstract
Positive-strand RNA [(+)RNA] viruses are important pathogens of humans, animals, and plants and replicate inside host cells by coopting numerous host factors and subcellular membranes. To gain insights into the assembly of viral replicase complexes (VRCs) and dissect the roles of various lipids and coopted host factors, we have reconstituted Tomato bushy stunt virus (TBSV) replicase using artificial giant unilamellar vesicles (GUVs). We demonstrate that reconstitution of VRCs on GUVs with endoplasmic reticulum (ER)-like phospholipid composition results in a complete cycle of replication and asymmetrical RNA synthesis, which is a hallmark of (+)RNA viruses. TBSV VRCs assembled on GUVs provide significant protection of the double-stranded RNA (dsRNA) replication intermediate against the dsRNA-specific RNase III. The lipid compositions of GUVs have pronounced effects on in vitro TBSV replication, including (-) and (+)RNA synthesis. The GUV-based assay has led to the discovery of the critical role of phosphatidylserine in TBSV replication and a novel role for phosphatidylethanolamine in asymmetrical (+)RNA synthesis. The GUV-based assay also showed stimulatory effects by phosphatidylinositol-3-phosphate [PI(3)P] and ergosterol on TBSV replication. We demonstrate that eEF1A and Hsp70 coopted replicase assembly factors, Vps34 phosphatidylinositol 3-kinase (PI3K) and the membrane-bending ESCRT factors, are required for reconstitution of the active TBSV VRCs in GUVs, further supporting that the novel GUV-based in vitro approach recapitulates critical steps and involves essential coopted cellular factors of the TBSV replication process. Taken together, this novel GUV assay will be highly suitable to dissect the functions of viral and cellular factors in TBSV replication.IMPORTANCE Understanding the mechanism of replication of positive-strand RNA viruses, which are major pathogens of plants, animals, and humans, can lead to new targets for antiviral interventions. These viruses subvert intracellular membranes for virus replication and coopt numerous host proteins, whose functions during virus replication are not yet completely defined. To dissect the roles of various host factors in Tomato bushy stunt virus (TBSV) replication, we have developed an artificial giant unilamellar vesicle (GUV)-based replication assay. The GUV-based in vitro approach recapitulates critical steps of the TBSV replication process. GUV-based reconstitution of the TBSV replicase revealed the need for a complex mixture of phospholipids, especially phosphatidylserine and phosphatidylethanolamine, in TBSV replication. The GUV-based approach will be useful to dissect the functions of essential coopted cellular factors.
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Affiliation(s)
- Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
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9
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Belyi Y. Targeting Eukaryotic mRNA Translation by Legionella pneumophila. Front Mol Biosci 2020; 7:80. [PMID: 32411722 PMCID: PMC7201127 DOI: 10.3389/fmolb.2020.00080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/07/2020] [Indexed: 02/01/2023] Open
Abstract
Legionella is a gram-negative microorganism and an infectious agent of pneumonia in humans. It is an intracellular pathogen and multiplies in different eukaryotic cells like amoebae, ciliated protozoa, macrophages, monocytes, and lung epithelial cells. Proliferation of L. pneumophila in eukaryotic cells depends on its type 4 secretion system, which delivers an arsenal of bacterial effector proteins to cytoplasm of its host. Once within the cytoplasm, effectors modify a broad range of host activities, including mRNA translation. Translation is inhibited by Legionella through the action of several effector proteins including Lgt1, Lgt2, Lgt3, SidI, LegK4, SidL, and RavX. Lgt1-3 and SidI target elongation factors: Lgt1-3 mono-glucosylate elongation factor eEF1A, while SidI binds eEF1A, and eEF1Bγ. Effector LegK4 inhibits protein synthesis by phosphorylating Hsp70 proteins, while SidL and RavX have no defined targets in protein synthesis machinery thus far. In addition to direct inhibition of protein synthesis, SidI also affects the stress response, whereas Lgt1-3 – unfolded protein response and cell-cycle progression of host cells. Whether manipulation of these processes is linked to canonical or non-canonical function(s) of targeted elongation factors remains unknown.
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Affiliation(s)
- Yury Belyi
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia
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10
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Inaba JI, Xu K, Kovalev N, Ramanathan H, Roy CR, Lindenbach BD, Nagy PD. Screening Legionella effectors for antiviral effects reveals Rab1 GTPase as a proviral factor coopted for tombusvirus replication. Proc Natl Acad Sci U S A 2019; 116:21739-21747. [PMID: 31591191 PMCID: PMC6815150 DOI: 10.1073/pnas.1911108116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial virulence factors or effectors are proteins targeted into host cells to coopt or interfere with cellular proteins and pathways. Viruses often coopt the same cellular proteins and pathways to support their replication in infected cells. Therefore, we screened the Legionella pneumophila effectors to probe virus-host interactions and identify factors that modulate tomato bushy stunt virus (TBSV) replication in yeast surrogate host. Among 302 Legionella effectors tested, 28 effectors affected TBSV replication. To unravel a coopted cellular pathway in TBSV replication, the identified DrrA effector from Legionella was further exploited. We find that expression of DrrA in yeast or plants blocks TBSV replication through inhibiting the recruitment of Rab1 small GTPase and endoplasmic reticulum-derived COPII vesicles into the viral replication compartment. TBSV hijacks Rab1 and COPII vesicles to create enlarged membrane surfaces and optimal lipid composition within the viral replication compartment. To further validate our Legionella effector screen, we used the Legionella effector LepB lipid kinase to confirm the critical proviral function of PI(3)P phosphoinositide and the early endosomal compartment in TBSV replication. We demonstrate the direct inhibitory activity of LegC8 effector on TBSV replication using a cell-free replicase reconstitution assay. LegC8 inhibits the function of eEF1A, a coopted proviral host factor. Altogether, the identified bacterial effectors with anti-TBSV activity could be powerful reagents in cell biology and virus-host interaction studies. This study provides important proof of concept that bacterial effector proteins can be a useful toolbox to identify host factors and cellular pathways coopted by (+)RNA viruses.
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Affiliation(s)
- Jun-Ichi Inaba
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546
| | - Kai Xu
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546
| | - Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546
| | - Harish Ramanathan
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Craig R Roy
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Brett D Lindenbach
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546;
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11
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Park JB, Kim YH, Yoo Y, Kim J, Jun SH, Cho JW, El Qaidi S, Walpole S, Monaco S, García-García AA, Wu M, Hays MP, Hurtado-Guerrero R, Angulo J, Hardwidge PR, Shin JS, Cho HS. Structural basis for arginine glycosylation of host substrates by bacterial effector proteins. Nat Commun 2018; 9:4283. [PMID: 30327479 PMCID: PMC6191443 DOI: 10.1038/s41467-018-06680-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/19/2018] [Indexed: 01/11/2023] Open
Abstract
The bacterial effector proteins SseK and NleB glycosylate host proteins on arginine residues, leading to reduced NF-κB-dependent responses to infection. Salmonella SseK1 and SseK2 are E. coli NleB1 orthologs that behave as NleB1-like GTs, although they differ in protein substrate specificity. Here we report that these enzymes are retaining glycosyltransferases composed of a helix-loop-helix (HLH) domain, a lid domain, and a catalytic domain. A conserved HEN motif (His-Glu-Asn) in the active site is important for enzyme catalysis and bacterial virulence. We observe differences between SseK1 and SseK2 in interactions with substrates and identify substrate residues that are critical for enzyme recognition. Long Molecular Dynamics simulations suggest that the HLH domain determines substrate specificity and the lid-domain regulates the opening of the active site. Overall, our data suggest a front-face SNi mechanism, explain differences in activities among these effectors, and have implications for future drug development against enteric pathogens.
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Affiliation(s)
- Jun Bae Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Young Hun Kim
- Department of Microbiology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Youngki Yoo
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Juyeon Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung-Hoon Jun
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Center for Electron Microscopy Research, Korea Basic Science Institute, Ochang, Chungbuk, 28119, Republic of Korea
| | - Jin Won Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Samuel Walpole
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Serena Monaco
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Ana A García-García
- BIFI, University of Zaragoza, BIFI-IQFR (CSIC) Joint Unit, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain
| | - Miaomiao Wu
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Michael P Hays
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Ramon Hurtado-Guerrero
- BIFI, University of Zaragoza, BIFI-IQFR (CSIC) Joint Unit, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, Zaragoza, 50018, Spain. .,Fundación ARAID, 50018, Zaragoza, Spain.
| | - Jesus Angulo
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Jeon-Soo Shin
- Department of Microbiology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea. .,Severance Biomedical Science Institute and Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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12
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Jank T, Belyi Y, Aktories K. Bacterial glycosyltransferase toxins. Cell Microbiol 2015; 17:1752-65. [DOI: 10.1111/cmi.12533] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/28/2022]
Affiliation(s)
- Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Yury Belyi
- Gamaleya Research Institute; Moscow 123098 Russia
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Klaus Aktories
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
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13
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So EC, Mattheis C, Tate EW, Frankel G, Schroeder GN. Creating a customized intracellular niche: subversion of host cell signaling by Legionella type IV secretion system effectors. Can J Microbiol 2015; 61:617-35. [PMID: 26059316 DOI: 10.1139/cjm-2015-0166] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Gram-negative facultative intracellular pathogen Legionella pneumophila infects a wide range of different protozoa in the environment and also human alveolar macrophages upon inhalation of contaminated aerosols. Inside its hosts, it creates a defined and unique compartment, termed the Legionella-containing vacuole (LCV), for survival and replication. To establish the LCV, L. pneumophila uses its Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effector proteins into the host cell. Although it has become apparent in the past years that these effectors subvert a multitude of cellular processes and allow Legionella to take control of host cell vesicle trafficking, transcription, and translation, the exact function of the vast majority of effectors still remains unknown. This is partly due to high functional redundancy among the effectors, which renders conventional genetic approaches to elucidate their role ineffective. Here, we review the current knowledge about Legionella T4SS effectors, highlight open questions, and discuss new methods that promise to facilitate the characterization of T4SS effector functions in the future.
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Affiliation(s)
- Ernest C So
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.,b Department of Chemistry, South Kensington Campus, Imperial College, London, SW7 2AZ, UK
| | - Corinna Mattheis
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Edward W Tate
- b Department of Chemistry, South Kensington Campus, Imperial College, London, SW7 2AZ, UK
| | - Gad Frankel
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
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14
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Liang DM, Liu JH, Wu H, Wang BB, Zhu HJ, Qiao JJ. Glycosyltransferases: mechanisms and applications in natural product development. Chem Soc Rev 2015; 44:8350-74. [DOI: 10.1039/c5cs00600g] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Glycosylation reactions mainly catalyzed by glycosyltransferases (Gts) occur almost everywhere in the biosphere, and always play crucial roles in vital processes.
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Affiliation(s)
- Dong-Mei Liang
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Jia-Heng Liu
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Hao Wu
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Bin-Bin Wang
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Hong-Ji Zhu
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Jian-Jun Qiao
- Department of Pharmaceutical Engineering
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
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15
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Computational modeling and experimental validation of the Legionella and Coxiella virulence-related type-IVB secretion signal. Proc Natl Acad Sci U S A 2013; 110:E707-15. [PMID: 23382224 DOI: 10.1073/pnas.1215278110] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Legionella and Coxiella are intracellular pathogens that use the virulence-related Icm/Dot type-IVB secretion system to translocate effector proteins into host cells during infection. These effectors were previously shown to contain a C-terminal secretion signal required for their translocation. In this research, we implemented a hidden semi-Markov model to characterize the amino acid composition of the signal, thus providing a comprehensive computational model for the secretion signal. This model accounts for dependencies among sites and captures spatial variation in amino acid composition along the secretion signal. To validate our model, we predicted and synthetically constructed an optimal secretion signal whose sequence is different from that of any known effector. We show that this signal efficiently translocates into host cells in an Icm/Dot-dependent manner. Additionally, we predicted in silico and experimentally examined the effects of mutations in the secretion signal, which provided innovative insights into its characteristics. Some effectors were found to lack a strong secretion signal according to our model. We demonstrated that these effectors were highly dependent on the IcmS-IcmW chaperons for their translocation, unlike effectors that harbor a strong secretion signal. Furthermore, our model is innovative because it enables searching ORFs for secretion signals on a genomic scale, which led to the identification and experimental validation of 20 effectors from Legionella pneumophila, Legionella longbeachae, and Coxiella burnetii. Our combined computational and experimental methodology is general and can be applied to the identification of a wide spectrum of protein features that lack sequence conservation but have similar amino acid characteristics.
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16
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Segal G. The Legionella pneumophila two-component regulatory systems that participate in the regulation of Icm/Dot effectors. Curr Top Microbiol Immunol 2013; 376:35-52. [PMID: 23918177 DOI: 10.1007/82_2013_346] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Legionella pneumophila, the causative agent of Legionnaires' disease, actively manipulates intracellular processes to establish a replication niche inside their host cells. The establishment of its replication niche requires a functional Icm/Dot type IV secretion system which translocates about 300 effector proteins into the host cells during infection. This enormous number of effectors should be coordinated at the level of gene expression, in order to be expressed and translocated at the correct time and appropriate amounts. One of the predominant ways in bacteria to regulate virulence gene expression is by the use of two-component systems (TCSs). To date, four TCSs have been shown to be involved in the regulation of Icm/Dot effector-encoding genes: The PmrAB and CpxRA TCSs that directly control, and the LetAS and LqsRS TCSs that indirectly control the level of expression of effector-encoding genes. According to our current knowledge, these four TCSs control the expression of about 70 effector-encoding genes. The regulation by different TCSs divides the effectors into groups of co-regulated effector-encoding genes that are probably co-expressed at a similar time during infection and might perform related functions. In addition, examples of interplay between these TCSs were already reported indicating that they form part of a regulatory network that orchestrates the expression of L. pneumophila effector-encoding genes during infection.
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Affiliation(s)
- Gil Segal
- The George S. Wise Faculty of Life Sciences, Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, 69978, Ramat-Aviv, Tel-Aviv, Israel,
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17
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Abstract
Legionella is a gram-negative bacterium and the causative pathogen of legionellosis-a severe pneumonia in humans. A large number of Legionella effectors interfere with numerous host cell functions, including intracellular vacuole trafficking and maturation, phospholipid metabolism, protein ubiquitination, pro-/anti-apoptotic balances or inflammatory responses. Moreover, eukaryotic protein synthesis is affected by L. pneumophila glucosyltransferases Lgt1, Lgt2, and Lgt3. Structurally, these enzymes are similar to large clostridial cytotoxins, use UDP-glucose as a co-substrate and modify a conserved serine residue (Ser-53) in elongation factor 1A (eEF1A). The ternary complex consisting of eEF1A, GTP, and aminoacylated-tRNA seems to be the substrate for Lgts. Studies with Saccharomyces cerevisiae corroborated that eEF1A is the major target responsible for Lgt-induced cytotoxic activity. In addition to Lgt proteins, Legionella produces other effector glycosyltransferase, including the modularly composed protein SetA, which displays tropism for early endosomal compartments, subverts host cell vesicle trafficking and demonstrates toxic activities toward yeast and mammalian cells. Here, our current knowledge about both groups of L. pneumophila glycosylating effectors is reviewed.
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18
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Ku B, Lee KH, Park WS, Yang CS, Ge J, Lee SG, Cha SS, Shao F, Heo WD, Jung JU, Oh BH. VipD of Legionella pneumophila targets activated Rab5 and Rab22 to interfere with endosomal trafficking in macrophages. PLoS Pathog 2012; 8:e1003082. [PMID: 23271971 PMCID: PMC3521694 DOI: 10.1371/journal.ppat.1003082] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 10/28/2012] [Indexed: 12/02/2022] Open
Abstract
Upon phagocytosis, Legionella pneumophila translocates numerous effector proteins into host cells to perturb cellular metabolism and immunity, ultimately establishing intracellular survival and growth. VipD of L. pneumophila belongs to a family of bacterial effectors that contain the N-terminal lipase domain and the C-terminal domain with an unknown function. We report the crystal structure of VipD and show that its C-terminal domain robustly interferes with endosomal trafficking through tight and selective interactions with Rab5 and Rab22. This domain, which is not significantly similar to any known protein structure, potently interacts with the GTP-bound active form of the two Rabs by recognizing a hydrophobic triad conserved in Rabs. These interactions prevent Rab5 and Rab22 from binding to downstream effectors Rabaptin-5, Rabenosyn-5 and EEA1, consequently blocking endosomal trafficking and subsequent lysosomal degradation of endocytic materials in macrophage cells. Together, this work reveals endosomal trafficking as a target of L. pneumophila and delineates the underlying molecular mechanism. Legionella pneumophila is a pathogen bacterium that causes Legionnaires' disease accompanied by severe pneumonia. Surprisingly, this pathogen invades and replicates inside macrophages, whose major function is to detect and destroy invading microorganisms. How L. pneumophila can be “immune” to this primary immune cell has been a focus of intensive research. Upon being engulfed by a macrophage cell, L. pneumophila translocates hundreds of bacterial proteins into this host cell. These proteins, called bacterial effectors, are thought to manipulate normal host cellular processes. However, which host molecules and how they are targeted by the bacterial effectors are largely unknown. In this study, we determined the three-dimensional structure of L. pneumophila effector protein VipD, whose function in macrophage was unknown. Ensuing analyses revealed that VipD selectively and tightly binds two host signaling proteins Rab5 and Rab22, which are key regulators of early endosomal vesicle trafficking. These interactions prevent the activated form of Rab5 and Rab22 from binding their downstream signaling proteins, resulting in the blockade of endosomal trafficking in macrophages. The presented work shows that L. pneumophila targets endosomal Rab proteins and delineates the underlying molecular mechanism, providing a new insight into the pathogen's strategies to dysregulate normal intracellular processes.
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Affiliation(s)
- Bonsu Ku
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Kwang-Hoon Lee
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Wei Sun Park
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Chul-Su Yang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jianning Ge
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- National Institute of Biological Sciences, Beijing, China
| | - Seong-Gyu Lee
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Sun-Shin Cha
- Marine Biotechnology Research Center, Korea Ocean Research and Development Institute, Ansan, Korea
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China
| | - Won Do Heo
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Jae U. Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Byung-Ha Oh
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
- * E-mail:
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19
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Recent structural and mechanistic insights into post-translational enzymatic glycosylation. Curr Opin Chem Biol 2012; 16:479-87. [PMID: 23142486 DOI: 10.1016/j.cbpa.2012.10.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/21/2012] [Accepted: 10/10/2012] [Indexed: 11/21/2022]
Abstract
Enzymatic glycosylation of proteins, a post-transitional modification of great significance, is carried out by diverse glycosyltransferases (GTs) that harness activated sugar donors, typically nucleotide or lipid-phosphate linked species. Recent work has seen a major increase in the study of the 3D structure and reaction mechanism of these enzymes. Key advances include the dissection of the classical O-glycosylating and N-glycosylating apparatus, revealing unusual folds and hitherto unconsidered chemical mechanisms for acceptor activation. There has been considerable success in the application of kinetic isotope effects and quantum simulations to address the controversial issue of the reaction mechanism of retaining GTs. New roles for old modifications, exemplified by potential epigenetic roles for glycosylation, have been discovered and there has also been a plethora of studies into important mammalian glycosylations that play key roles in cellular biology, opening up new targets for chemical intervention approaches.
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20
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Identification of two Legionella pneumophila effectors that manipulate host phospholipids biosynthesis. PLoS Pathog 2012; 8:e1002988. [PMID: 23133385 PMCID: PMC3486869 DOI: 10.1371/journal.ppat.1002988] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 08/28/2012] [Indexed: 12/31/2022] Open
Abstract
The intracellular pathogen Legionella pneumophila translocates a large number of effector proteins into host cells via the Icm/Dot type-IVB secretion system. Some of these effectors were shown to cause lethal effect on yeast growth. Here we characterized one such effector (LecE) and identified yeast suppressors that reduced its lethal effect. The LecE lethal effect was found to be suppressed by the over expression of the yeast protein Dgk1 a diacylglycerol (DAG) kinase enzyme and by a deletion of the gene encoding for Pah1 a phosphatidic acid (PA) phosphatase that counteracts the activity of Dgk1. Genetic analysis using yeast deletion mutants, strains expressing relevant yeast genes and point mutations constructed in the Dgk1 and Pah1 conserved domains indicated that LecE functions similarly to the Nem1-Spo7 phosphatase complex that activates Pah1 in yeast. In addition, by using relevant yeast genetic backgrounds we examined several L. pneumophila effectors expected to be involved in phospholipids biosynthesis and identified an effector (LpdA) that contains a phospholipase-D (PLD) domain which caused lethal effect only in a dgk1 deletion mutant of yeast. Additionally, LpdA was found to enhance the lethal effect of LecE in yeast cells, a phenomenon which was found to be dependent on its PLD activity. Furthermore, to determine whether LecE and LpdA affect the levels or distribution of DAG and PA in-vivo in mammalian cells, we utilized fluorescent DAG and PA biosensors and validated the notion that LecE and LpdA affect the in-vivo levels and distribution of DAG and PA, respectively. Finally, we examined the intracellular localization of both LecE and LpdA in human macrophages during L. pneumophila infection and found that both effectors are localized to the bacterial phagosome. Our results suggest that L. pneumophila utilize at least two effectors to manipulate important steps in phospholipids biosynthesis. Legionella pneumophila is an intracellular pathogen that causes a severe pneumonia known as Legionnaires' disease. Following infection, the bacteria use a Type-IVB secretion system to translocate multiple effector proteins into macrophages and generate the Legionella-containing vacuole (LCV). The formation of the LCV involves the recruitment of specific bacterial effectors and host cell factors to the LCV as well as changes in its lipids composition. By screening L. pneumophila effectors for yeast growth inhibition, we have identified an effector, named LecE, that strongly inhibits yeast growth. By using yeast genetic tools, we found that LecE activates the yeast lipin homolog – Pah1, an enzyme that catalyzes the conversion of diacylglycerol to phosphatidic acid, these two molecules function as bioactive lipid signaling molecules in eukaryotic cells. In addition, by using yeast deletion mutants in genes relevant to lipids biosynthesis, we have identified another effector, named LpdA, which function as a phospholipase-D enzyme. Both effectors were found to be localized to the LCV during infection. Our results reveal a possible mechanism by which an intravacuolar pathogen might change the lipid composition of the vacuole in which it resides, a process that might lead to the recruitment of specific bacterial and host cell factors to the vacoule.
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21
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Ramos PIP, Picão RC, Vespero EC, Pelisson M, Zuleta LFG, Almeida LGP, Gerber AL, Vasconcelos ATR, Gales AC, Nicolás MF. Pyrosequencing-based analysis reveals a novel capsular gene cluster in a KPC-producing Klebsiella pneumoniae clinical isolate identified in Brazil. BMC Microbiol 2012; 12:173. [PMID: 22882772 PMCID: PMC3438125 DOI: 10.1186/1471-2180-12-173] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/23/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND An important virulence factor of Klebsiella pneumoniae is the production of capsular polysaccharide (CPS), a thick mucus layer that allows for evasion of the host's defense and creates a barrier against antibacterial peptides. CPS production is driven mostly by the expression of genes located in a locus called cps, and the resulting structure is used to distinguish between different serotypes (K types). In this study, we report the unique genetic organization of the cps cluster from K. pneumoniae Kp13, a clinical isolate recovered during a large outbreak of nosocomial infections that occurred in a Brazilian teaching hospital. RESULTS A pyrosequencing-based approach showed that the cps region of Kp13 (cpsKp13) is 26.4 kbp in length and contains genes common, although not universal, to other strains, such as the rmlBADC operon that codes for L-rhamnose synthesis. cpsKp13 also presents some unique features, like the inversion of the wzy gene and a unique repertoire of glycosyltransferases. In silico comparison of cpsKp13 RFLP pattern with 102 previously published cps PCR-RFLP patterns showed that cpsKp13 is distinct from the C patterns of all other K serotypes. Furthermore, in vitro serotyping showed only a weak reaction with capsular types K9 and K34. We confirm that K9 cps shares common genes with cpsKp13 such as the rmlBADC operon, but lacks features like uge and Kp13-specific glycosyltransferases, while K34 capsules contain three of the five sugars that potentially form the Kp13 CPS. CONCLUSIONS We report the first description of a cps cluster from a Brazilian clinical isolate of a KPC-producing K. pneumoniae. The gathered data including K-serotyping support that Kp13's K-antigen belongs to a novel capsular serotype. The CPS of Kp13 probably includes L-rhamnose and D-galacturonate in its structure, among other residues. Because genes involved in L-rhamnose biosynthesis are absent in humans, this pathway may represent potential targets for the development of antimicrobial agents. Studying the capsular serotypes of clinical isolates is of great importance for further development of vaccines and/or novel therapeutic agents. The distribution of K-types among multidrug-resistant isolates is unknown, but our findings may encourage scientists to perform K-antigen typing of KPC-producing strains worldwide.
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22
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Belyi Y, Tartakovskaya D, Tais A, Fitzke E, Tzivelekidis T, Jank T, Rospert S, Aktories K. Elongation factor 1A is the target of growth inhibition in yeast caused by Legionella pneumophila glucosyltransferase Lgt1. J Biol Chem 2012; 287:26029-37. [PMID: 22685293 DOI: 10.1074/jbc.m112.372672] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Legionella is a pathogenic Gram-negative bacterium that can multiply inside of eukaryotic cells. It translocates numerous bacterial effector proteins into target cells to transform host phagocytes into a niche for replication. One effector of Legionella pneumophila is the glucosyltransferase Lgt1, which modifies serine 53 in mammalian elongation factor 1A (eEF1A), resulting in inhibition of protein synthesis and cell death. Here, we demonstrate that similar to mammalian cells, Lgt1 was severely toxic when produced in yeast and effectively inhibited in vitro protein synthesis. Saccharomyces cerevisiae strains, which were deleted of endogenous eEF1A but harbored a mutant eEF1A not glucosylated by Lgt1, were resistant toward the bacterial effector. In contrast, deletion of Hbs1, which is also an in vitro substrate of the glucosyltransferase, did not influence the toxic effects of Lgt1. Serial mutagenesis in yeast showed that Phe(54), Tyr(56) and Trp(58), located immediately downstream of serine 53 of eEF1A, are essential for the function of the elongation factor. Replacement of serine 53 by glutamic acid, mimicking phosphorylation, produced a non-functional eEF1A, which failed to support growth of S. cerevisiae. Our data indicate that Lgt1-induced lethal effect in yeast depends solely on eEF1A. The region of eEF1A encompassing serine 53 plays a critical role in functioning of the elongation factor.
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Affiliation(s)
- Yury Belyi
- Gamaleya Research Institute, Moscow 123098, Russia
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23
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Tzivelekidis T, Jank T, Pohl C, Schlosser A, Rospert S, Knudsen CR, Rodnina MV, Belyi Y, Aktories K. Aminoacyl-tRNA-charged eukaryotic elongation factor 1A is the bona fide substrate for Legionella pneumophila effector glucosyltransferases. PLoS One 2011; 6:e29525. [PMID: 22216304 PMCID: PMC3245282 DOI: 10.1371/journal.pone.0029525] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 11/30/2011] [Indexed: 01/08/2023] Open
Abstract
Legionella pneumophila, which is the causative organism of Legionnaireś disease, translocates numerous effector proteins into the host cell cytosol by a type IV secretion system during infection. Among the most potent effector proteins of Legionella are glucosyltransferases (lgt's), which selectively modify eukaryotic elongation factor (eEF) 1A at Ser-53 in the GTP binding domain. Glucosylation results in inhibition of protein synthesis. Here we show that in vitro glucosylation of yeast and mouse eEF1A by Lgt3 in the presence of the factors Phe-tRNAPhe and GTP was enhanced 150 and 590-fold, respectively. The glucosylation of eEF1A catalyzed by Lgt1 and 2 was increased about 70-fold. By comparison of uncharged tRNA with two distinct aminoacyl-tRNAs (His-tRNAHis and Phe-tRNAPhe) we could show that aminoacylation is crucial for Lgt-catalyzed glucosylation. Aminoacyl-tRNA had no effect on the enzymatic properties of lgt's and did not enhance the glucosylation rate of eEF1A truncation mutants, consisting of the GTPase domain only or of a 5 kDa peptide covering Ser-53 of eEF1A. Furthermore, binding of aminoacyl-tRNA to eEF1A was not altered by glucosylation. Taken together, our data suggest that the ternary complex, consisting of eEF1A, aminoacyl-tRNA and GTP, is the bona fide substrate for lgt's.
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Affiliation(s)
- Tina Tzivelekidis
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg, Germany
- Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Thomas Jank
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg, Germany
| | - Corinna Pohl
- Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Andreas Schlosser
- Zentrum für Biosystemanalyse, Core Facility Proteomics, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Sabine Rospert
- Institut für Biochemie und Mikrobiologie, ZBMZ, Albert-Ludwigs-Universität, Freiburg, Germany
| | | | | | - Yury Belyi
- Gamaleya Research Institute, Moscow, Russia
| | - Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg, Germany
- * E-mail:
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Belyi Y, Jank T, Aktories K. Effector glycosyltransferases in legionella. Front Microbiol 2011; 2:76. [PMID: 21833323 PMCID: PMC3153043 DOI: 10.3389/fmicb.2011.00076] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 03/31/2011] [Indexed: 11/13/2022] Open
Abstract
Legionella causes severe pneumonia in humans. The pathogen produces an array of effectors, which interfere with host cell functions. Among them are the glucosyltransferases Lgt1, Lgt2 and Lgt3 from L. pneumophila. Lgt1 and Lgt2 are produced predominately in the post-exponential phase of bacterial growth, while synthesis of Lgt3 is induced mainly in the lag-phase before intracellular replication of bacteria starts. Lgt glucosyltransferases are structurally similar to clostridial glucosylating toxins. The enzymes use UDP–glucose as a donor substrate and modify eukaryotic elongation factor eEF1A at serine-53. This modification results in inhibition of protein synthesis and death of target cells.In addition to Lgts, Legionella genomes disclose several genes, coding for effector proteins likely to possess glycosyltransferase activities, including SetA (subversion of eukaryotic vesicle trafficking A), which influences vesicular trafficking in the yeast model system and displays tropism for late endosomal/lysosomal compartments of mammalian cells. This review mainly discusses recent results on the structure–function relationship of Lgt glucosyltransferases.
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Affiliation(s)
- Yury Belyi
- Gamaleya Research Institute Moscow, Russia
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Bobard A, Mellouk N, Enninga J. Spotting the right location- imaging approaches to resolve the intracellular localization of invasive pathogens. Biochim Biophys Acta Gen Subj 2010; 1810:297-307. [PMID: 21029766 DOI: 10.1016/j.bbagen.2010.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 10/16/2010] [Accepted: 10/18/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND A common strategy of microbial pathogens is to invade host cells during infection. The invading microbes explore different intracellular compartments to find their preferred niche. SCOPE OF REVIEW Imaging has been instrumental to unravel paradigms of pathogen entry, to identify their exact intracellular location, and to understand the underlying mechanisms for the formation of pathogen-containing niches. Here, we provide an overview of imaging techniques that have been applied to monitor the intracellular lifestyle of pathogens, focusing mainly on bacteria that either remain in vacuolar-bound compartments or rupture the endocytic vacuole to escape into the host's cellular cytoplasm. MAJOR CONCLUSIONS We will depict common molecular and cellular paradigms that are preferentially exploited by pathogens. A combination of electron microscopy, fluorescence microscopy, and time-lapse microscopy has been the driving force to reveal underlying cell biological processes. Furthermore, the development of highly sensitive and specific fluorescent sensor molecules has allowed for the identification of functional aspects of niche formation by intracellular pathogens. GENERAL SIGNIFICANCE Currently, we are beginning to understand the sophistication of the invasion strategies used by bacterial pathogens during the infection process- innovative imaging has been a key ingredient for this. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine.
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Affiliation(s)
- Alexandre Bobard
- Institut Pasteur, Groupe "Dynamique des Interactions Hôte-Pathogène, Paris, France
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