1
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Kloet MS, Mukhopadhyay R, Mukherjee R, Misra M, Jeong M, Talavera Ormeño CMP, Moutsiopoulou A, Tjokrodirijo RTN, van Veelen PA, Shin D, Đikić I, Sapmaz A, Kim RQ, van der Heden van Noort GJ. Covalent Probes To Capture Legionella pneumophila Dup Effector Enzymes. J Am Chem Soc 2024; 146:26957-26964. [PMID: 39288007 PMCID: PMC11450808 DOI: 10.1021/jacs.4c08168] [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: 06/18/2024] [Revised: 09/06/2024] [Accepted: 09/09/2024] [Indexed: 09/19/2024]
Abstract
Upon infection of host cells, Legionella pneumophila releases a multitude of effector enzymes into the cell's cytoplasm that hijack a plethora of cellular activities, including the host ubiquitination pathways. Effectors belonging to the SidE-family are involved in noncanonical serine phosphoribosyl ubiquitination of host substrate proteins contributing to the formation of a Legionella-containing vacuole that is crucial in the onset of Legionnaires' disease. This dynamic process is reversed by effectors called Dups that hydrolyze the phosphodiester in the phosphoribosyl ubiquitinated protein. We installed reactive warheads on chemically prepared ribosylated ubiquitin to generate a set of probes targeting these Legionella enzymes. In vitro tests on recombinant DupA revealed that a vinyl sulfonate warhead was most efficient in covalent complex formation. Mutagenesis and X-ray crystallography approaches were used to identify the site of covalent cross-linking to be an allosteric cysteine residue. The subsequent application of this probe highlights the potential to selectively enrich the Dup enzymes from Legionella-infected cell lysates.
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Affiliation(s)
- Max S. Kloet
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
| | - Rishov Mukhopadhyay
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
| | - Rukmini Mukherjee
- Buchmann
Institute for Molecular Life Sciences, Goethe
University Frankfurt am Main, 60438, Frankfurt am Main, Germany
| | - Mohit Misra
- Buchmann
Institute for Molecular Life Sciences, Goethe
University Frankfurt am Main, 60438, Frankfurt am Main, Germany
| | - Minwoo Jeong
- Department
of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 03722, Seoul, Republic of Korea
| | - Cami M. P. Talavera Ormeño
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
| | - Angeliki Moutsiopoulou
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
| | - Rayman T. N. Tjokrodirijo
- Centre
for Proteomics and Metabolomics, Leiden
University Medical Centre, 2300 RC, Leiden, The Netherlands
| | - Peter A. van Veelen
- Centre
for Proteomics and Metabolomics, Leiden
University Medical Centre, 2300 RC, Leiden, The Netherlands
| | - Donghyuk Shin
- Department
of Systems Biology, College of Life Science and Biotechnology, Yonsei University, 03722, Seoul, Republic of Korea
| | - Ivan Đikić
- Buchmann
Institute for Molecular Life Sciences, Goethe
University Frankfurt am Main, 60438, Frankfurt am Main, Germany
| | - Aysegul Sapmaz
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
| | - Robbert Q. Kim
- Department
of Cell and Chemical Biology, Leiden University
Medical Centre, 2333 ZC, Leiden, The Netherlands
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2
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Cobe BL, Dey S, Minasov G, Inniss N, Satchell KJF, Cianciotto NP. Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB. mBio 2024; 15:e0119824. [PMID: 38832773 PMCID: PMC11253643 DOI: 10.1128/mbio.01198-24] [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] [Received: 04/18/2024] [Accepted: 04/28/2024] [Indexed: 06/05/2024] Open
Abstract
Stenotrophomonas maltophilia expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report the structure of TfcB, comprising an N-terminal domain similar to the catalytic domain of glycosyl hydrolase (GH-19) chitinases and a C-terminal domain for recognition and translocation by the T4SS. Utilizing a two-hybrid assay to measure effector interactions with the T4SS coupling protein VirD4, we documented the existence of five more T4SS substrates. One of these was protein 20845, an annotated nuclease. A S. maltophilia mutant lacking the gene for 20845 was impaired for killing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Moreover, the cloned 20845 gene conferred robust toxicity, with the recombinant E. coli being rescued when 20845 was co-expressed with its cognate immunity protein. The 20845 effector was an 899 amino-acid protein, comprised of a GHH-nuclease domain in its N-terminus, a large central region of indeterminant function, and a C-terminus for secretion. Engineered variants of the 20845 gene that had mutations in the predicted catalytic site did not impede E. coli, indicating that the antibacterial effect of 20845 involves its nuclease activity. Using flow cytometry with DNA staining, we determined that 20845, but not its mutant variants, confers a loss in DNA content of target bacteria. Database searches revealed that uncharacterized homologs of 20845 occur within a range of bacteria. These data indicate that the S. maltophilia T4SS promotes interbacterial competition through the action of multiple toxic effectors, including a potent, novel DNase.IMPORTANCEStenotrophomonas maltophilia is a multi-drug-resistant, Gram-negative bacterium that is an emerging pathogen of humans. Patients with cystic fibrosis are particularly susceptible to S. maltophilia infection. In hospital water systems and various types of infections, S. maltophilia co-exists with other bacteria, including other pathogens such as Pseudomonas aeruginosa. We previously demonstrated that S. maltophilia has a functional VirB/D4 type VI protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria. Since most work on antibacterial systems involves the type VI secretion system, this observation remains noteworthy. Moreover, S. maltophilia currently stands alone as a model for a human pathogen expressing an antibacterial T4SS. Using biochemical, genetic, and cell biological approaches, we now report both the discovery of a novel antibacterial nuclease (TfdA) and the first structural determination of a bactericidal T4SS effector (TfcB).
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Affiliation(s)
- Brandi L. Cobe
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Supratim Dey
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - George Minasov
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nicole Inniss
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Karla J. F. Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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3
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Steinbach A, Bhadkamkar V, Jimenez-Morales D, Stevenson E, Jang GM, Krogan NJ, Swaney DL, Mukherjee S. Cross-family small GTPase ubiquitination by the intracellular pathogen Legionella pneumophila. Mol Biol Cell 2024; 35:ar27. [PMID: 38117589 PMCID: PMC10916871 DOI: 10.1091/mbc.e23-06-0260] [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: 07/03/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 12/22/2023] Open
Abstract
The intracellular bacterial pathogen Legionella pneumophila (L.p.) manipulates eukaryotic host ubiquitination machinery to form its replicative vacuole. While nearly 10% of L.p.'s ∼330 secreted effector proteins are ubiquitin ligases or deubiquitinases, a comprehensive measure of temporally resolved changes in the endogenous host ubiquitinome during infection has not been undertaken. To elucidate how L.p. hijacks host cell ubiquitin signaling, we generated a proteome-wide analysis of changes in protein ubiquitination during infection. We discover that L.p. infection increases ubiquitination of host regulators of subcellular trafficking and membrane dynamics, most notably ∼40% of mammalian Ras superfamily small GTPases. We determine that these small GTPases undergo nondegradative ubiquitination at the Legionella-containing vacuole (LCV) membrane. Finally, we find that the bacterial effectors SidC/SdcA play a central role in cross-family small GTPase ubiquitination, and that these effectors function upstream of SidE family ligases in the polyubiquitination and retention of GTPases in the LCV membrane. This work highlights the extensive reconfiguration of host ubiquitin signaling by bacterial effectors during infection and establishes simultaneous ubiquitination of small GTPases across the Ras superfamily as a novel consequence of L.p. infection. Our findings position L.p. as a tool to better understand how small GTPases can be regulated by ubiquitination in uninfected contexts.
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Affiliation(s)
- Adriana Steinbach
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
| | - Varun Bhadkamkar
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
| | - David Jimenez-Morales
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA 94309
| | - Erica Stevenson
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Gwendolyn M. Jang
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Nevan J. Krogan
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Danielle L. Swaney
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Shaeri Mukherjee
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
- Chan Zuckerberg Biohub, San Francisco, CA 94158
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4
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Graham CI, MacMartin TL, de Kievit TR, Brassinga AKC. Molecular regulation of virulence in Legionella pneumophila. Mol Microbiol 2024; 121:167-195. [PMID: 37908155 DOI: 10.1111/mmi.15172] [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: 05/31/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 11/02/2023]
Abstract
Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.
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Affiliation(s)
- Christopher I Graham
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teassa L MacMartin
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R de Kievit
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
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5
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Sharma R, Adams M, Griffith-Jones S, Sahr T, Gomez-Valero L, Weis F, Hons M, Gharbi S, Berkane R, Stolz A, Buchrieser C, Bhogaraju S. Structural basis for the toxicity of Legionella pneumophila effector SidH. Nat Commun 2023; 14:7068. [PMID: 37923743 PMCID: PMC10624908 DOI: 10.1038/s41467-023-42683-8] [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: 04/26/2023] [Accepted: 10/17/2023] [Indexed: 11/06/2023] Open
Abstract
Legionella pneumophila (LP) secretes more than 300 effectors into the host cytosol to facilitate intracellular replication. One of these effectors, SidH, 253 kDa in size with no sequence similarity to proteins of known function is toxic when overexpressed in host cells. SidH is regulated by the LP metaeffector LubX which targets SidH for degradation in a temporal manner during LP infection. The mechanism underlying the toxicity of SidH and its role in LP infection are unknown. Here, we determined the cryo-EM structure of SidH at 2.7 Å revealing a unique alpha helical arrangement with no overall similarity to known protein structures. Surprisingly, purified SidH came bound to a E. coli EF-Tu/t-RNA/GTP ternary complex which could be modeled into the cryo-EM density. Mutation of residues disrupting the SidH-tRNA interface and SidH-EF-Tu interface abolish the toxicity of overexpressed SidH in human cells, a phenotype confirmed in infection of Acanthamoeba castellani. We also present the cryo-EM structure of SidH in complex with a U-box domain containing ubiquitin ligase LubX delineating the mechanism of regulation of SidH. Our data provide the basis for the toxicity of SidH and into its regulation by the metaeffector LubX.
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Affiliation(s)
- Rahul Sharma
- European Molecular Biology Laboratory, 71 avenue des Martyrs, 38042, Grenoble, France
| | - Michael Adams
- European Molecular Biology Laboratory, 71 avenue des Martyrs, 38042, Grenoble, France
| | | | - Tobias Sahr
- Institut Pasteur, Université Paris Cité, Biologie des Bactéries Intracellulaires and CNRS UMR 6047, 75724, Paris, France
| | - Laura Gomez-Valero
- Institut Pasteur, Université Paris Cité, Biologie des Bactéries Intracellulaires and CNRS UMR 6047, 75724, Paris, France
| | - Felix Weis
- European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Michael Hons
- European Molecular Biology Laboratory, 71 avenue des Martyrs, 38042, Grenoble, France
| | - Sarah Gharbi
- European Molecular Biology Laboratory, 71 avenue des Martyrs, 38042, Grenoble, France
| | - Rayene Berkane
- Institute of Biochemistry II, Goethe University Frankfurt - Medical Faculty, University Hospital, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Alexandra Stolz
- Institute of Biochemistry II, Goethe University Frankfurt - Medical Faculty, University Hospital, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Carmen Buchrieser
- Institut Pasteur, Université Paris Cité, Biologie des Bactéries Intracellulaires and CNRS UMR 6047, 75724, Paris, France
| | - Sagar Bhogaraju
- European Molecular Biology Laboratory, 71 avenue des Martyrs, 38042, Grenoble, France.
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6
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Kim S, Isberg RR. The Sde phosphoribosyl-linked ubiquitin transferases protect the Legionella pneumophila vacuole from degradation by the host. Proc Natl Acad Sci U S A 2023; 120:e2303942120. [PMID: 37549300 PMCID: PMC10437418 DOI: 10.1073/pnas.2303942120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/05/2023] [Indexed: 08/09/2023] Open
Abstract
Legionella pneumophila grows intracellularly within the membrane-bound Legionella-containing vacuole (LCV) established by proteins translocated via the bacterial type IV secretion system (T4SS). The Sde family, one such group of translocated proteins, catalyzes phosphoribosyl-ubiquitin (pR-Ub) modification of target substrates. Mutational loss of the entire Sde family results in small defects in intracellular growth, making it difficult to identify a clear role for this posttranslational modification in supporting the intracellular lifestyle. Therefore, mutations that aggravate the loss of sde genes and caused intracellular growth defects were identified, providing a mechanistic connection between Sde function and vacuole biogenesis. These double mutants drove the formation of LCVs that showed vacuole disintegration within 2 h of bacterial contact. Sde proteins appeared critical for blocking access of membrane-disruptive early endosomal membrane material to the vacuole, as RNAi depletion of endosomal pathway components partially restored LCV integrity. The role of Sde proteins in preventing host degradation of the LCV was limited to the earliest stages of infection. The time that Sde proteins could prevent vacuole disruption, however, was extended by deletion of sidJ, which encodes a translocated protein that inactivates Sde protein active sites. These results indicate that Sde proteins act as temporally regulated vacuole guards during the establishment of the replication niche, possibly by constructing a physical barrier that blocks access of disruptive host compartments during the earliest steps of LCV biogenesis.
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Affiliation(s)
- Seongok Kim
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA02111
| | - Ralph R. Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA02111
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7
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Kim S, Isberg RR. The Sde Phosphoribosyl-Linked Ubiquitin Transferases protect the Legionella pneumophila vacuole from degradation by the host. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.19.533379. [PMID: 36993347 PMCID: PMC10055210 DOI: 10.1101/2023.03.19.533379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Legionella pneumophila grows intracellularly within a host membrane-bound vacuole that is formed in response to a bacterial type IV secretion system (T4SS). T4SS translocated Sde proteins promote phosphoribosyl-linked ubiquitination of endoplasmic reticulum protein Rtn4, but the role played by this modification is obscure due to lack of clear growth defects of mutants. To identify the steps in vacuole biogenesis promoted by these proteins, mutations were identified that unmasked growth defects in Δ sde strains. Mutations in the sdhA , ridL and legA3 genes aggravated the Δ sde fitness defect, resulting in disruption of the Legionella -containing vacuole (LCV) membrane within 2 hrs of bacterial contact with host cells. Depletion of Rab5B and sorting nexin 1 partially bypassed loss of Sde proteins, consistent with Sde blocking early endosome and retrograde trafficking, similar to roles previously demonstrated for SdhA and RidL proteins. Sde protein protection of LCV lysis was only observed shortly after infection, presumably because Sde proteins are inactivated by the metaeffector SidJ during the course of infection. Deletion of SidJ extended the time that Sde proteins could prevent vacuole disruption, indicating that Sde proteins are negatively regulated at the posttranslational level and are limited to protecting membrane integrity at the earliest stages of replication. Transcriptional analysis was consistent with this timing model for an early point of execution of Sde protein. Therefore, Sde proteins act as temporally-regulated vacuole guards during establishment of the replication niche, possibly by constructing a physical barrier that blocks access of disruptive host compartments early during biogenesis of the LCV. Significance statement Maintaining replication compartment integrity is critical for growth of intravacuolar pathogens within host cells. By identifying genetically redundant pathways, Legionella pneumophila Sde proteins that promote phosphoribosyl-linked ubiquitination of target eukaryotic proteins are shown to be temporally-regulated vacuole guards, preventing replication vacuole dissolution during early stages of infection. As targeting of reticulon 4 by these proteins leads to tubular endoplasmic reticulum aggregation, Sde proteins are likely to construct a barrier that blocks access of disruptive early endosomal compartments to the replication vacuole. Our study provides a new framework for how vacuole guards function to support biogenesis of the L. pneumophila replicative niche.
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Affiliation(s)
- Seongok Kim
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
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8
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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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9
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Gutierrez MG, Enninga J. Intracellular niche switching as host subversion strategy of bacterial pathogens. Curr Opin Cell Biol 2022; 76:102081. [PMID: 35487154 DOI: 10.1016/j.ceb.2022.102081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/08/2022] [Accepted: 03/13/2022] [Indexed: 11/03/2022]
Abstract
Numerous bacterial pathogens "confine" themselves within host cells with an intracellular localization as main or exclusive niche. Many of them switch dynamically between a membrane-bound or cytosolic lifestyle. This requires either membrane damage and/or repair of the bacterial-containing compartment. Niche switching has profound consequences on how the host cell recognizes the pathogens in time and space for elimination. Moreover, niche switching impacts how bacteria communicate with host cells to obtain nutrients, and it affects the accessibility to antibiotics. Understanding the local environments and cellular phenotypes that lead to niche switching is critical for developing new host-targeted antimicrobial strategies, and has the potential to shed light into fundamental cellular processes.
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Affiliation(s)
- Maximiliano G Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit and UMR3691 CNRS, Institut Pasteur, Paris, France; Université de Paris, Sorbonne Paris Cité, Paris, France.
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10
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VAMP3 and VAMP8 regulate the development and functionality of parasitophorous vacuoles housing Leishmania amazonensis. Infect Immun 2022; 90:e0018321. [PMID: 35130453 DOI: 10.1128/iai.00183-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To colonize mammalian phagocytic cells, the parasite Leishmania remodels phagosomes into parasitophorous vacuoles that can be either tight-fitting individual or communal. The molecular and cellular bases underlying the biogenesis and functionality of these two types of vacuoles are poorly understood. In this study, we investigated the contribution of host cell Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor proteins to the expansion and functionality of communal vacuoles as well as on the replication of the parasite. The differential recruitment patterns of Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor to communal vacuoles harboring L. amazonensis and to individual vacuoles housing L. major led us to further investigate the roles of VAMP3 and VAMP8 in the interaction of Leishmania with its host cell. We show that whereas VAMP8 contributes to optimal expansion of communal vacuoles, VAMP3 negatively regulates L. amazonensis replication, vacuole size, as well as antigen cross-presentation. In contrast, neither proteins has an impact on the fate of L. major. Collectively, our data support a role for both VAMP3 and VAMP8 in the development and functionality of L. amazonensis-harboring communal parasitophorous vacuoles.
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11
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SdhA blocks disruption of the Legionella-containing vacuole by hijacking the OCRL phosphatase. Cell Rep 2021; 37:109894. [PMID: 34731604 PMCID: PMC8669613 DOI: 10.1016/j.celrep.2021.109894] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 07/27/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022] Open
Abstract
Legionella pneumophila grows intracellularly within a replication vacuole via action of Icm/Dot-secreted proteins. One such protein, SdhA, maintains the integrity of the vacuolar membrane, thereby preventing cytoplasmic degradation of bacteria. We show here that SdhA binds and blocks the action of OCRL (OculoCerebroRenal syndrome of Lowe), an inositol 5-phosphatase pivotal for controlling endosomal dynamics. OCRL depletion results in enhanced vacuole integrity and intracellular growth of a sdhA mutant, consistent with OCRL participating in vacuole disruption. Overexpressed SdhA alters OCRL function, enlarging endosomes, driving endosomal accumulation of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), and interfering with endosomal trafficking. SdhA interrupts Rab guanosine triphosphatase (GTPase)-OCRL interactions by binding to the OCRL ASPM-SPD2-Hydin (ASH) domain, without directly altering OCRL 5-phosphatase activity. The Legionella vacuole encompassing the sdhA mutant accumulates OCRL and endosomal antigen EEA1 (Early Endosome Antigen 1), consistent with SdhA blocking accumulation of OCRL-containing endosomal vesicles. Therefore, SdhA hijacking of OCRL is associated with blocking trafficking events that disrupt the pathogen vacuole.
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Zhang M, McEwen JM, Sjoblom NM, Kotewicz KM, Isberg RR, Scheck RA. Members of the Legionella pneumophila Sde family target tyrosine residues for phosphoribosyl-linked ubiquitination. RSC Chem Biol 2021; 2:1509-1519. [PMID: 34704056 PMCID: PMC8496037 DOI: 10.1039/d1cb00088h] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/28/2021] [Indexed: 12/23/2022] Open
Abstract
Legionella pneumophila establishes a replication vacuole by translocating hundreds of protein effectors through a type IV secretion system (T4SS). Among these translocated effectors are members of the Sde family, which catalyze phosphoribosyl-linked ubiquitination (pR-Ub) of host targets. Previous work has posited that Sde proteins solely target serine (Ser) residues within acceptor protein substrates. We show here that SdeC-mediated pR-Ub modification results from a stepwise reaction that also modifies tyrosine (Tyr) residues. Unexpectedly, the presence of an HA tag on Ub resulted in poly-pR-ubiquitination, consistent with the HA tag acting as an acceptor target. Interrogation of phosphoribosyl-linked HA-Ub revealed that Tyr4 was the preferred targeted residue, based on LC-MS/MS analysis of the crosslinked product. Further analysis using synthetic HA variants revealed promiscuous modification of Tyr, as crosslinking was prevented only by constructing a triple mutant in which all three Tyr within the HA sequence were substituted with Phe. Although previous work has indicated that Ser is the sole acceptor residue, we found no evidence of Ser preference over Tyr using Tyr → Ser replacement mutants. This work demonstrates that pR-ubiquitination by the Sde family is not limited to Ser-modification as previously proposed, and broadens the potential sites targeted by this family. During infection, Legionella pneumophila translocates hundreds of effectors into host cells. Among these, the Sde family effector SdeC catalyzes atypical ubiquitination of host targets at tyrosine, not only serine, residues.![]()
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Affiliation(s)
- Mengyun Zhang
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine Boston MA USA .,Graduate Program in Molecular Microbiology, Tufts University Graduate School of Biomedical Sciences Boston MA USA
| | | | | | - Kristin M Kotewicz
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine Boston MA USA .,Graduate Program in Molecular Microbiology, Tufts University Graduate School of Biomedical Sciences Boston MA USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine Boston MA USA
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Zhan XY, Yang JL, Zhou X, Qian YC, Huang K, Sun H, Wang H, Leng Y, Huang B, He Y. Virulence effector SidJ evolution in Legionella pneumophila is driven by positive selection and intragenic recombination. PeerJ 2021; 9:e12000. [PMID: 34458026 PMCID: PMC8378335 DOI: 10.7717/peerj.12000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/27/2021] [Indexed: 11/20/2022] Open
Abstract
Effector proteins translocated by the Dot/Icm type IV secretion system determine the virulence of Legionella pneumophila (L. pneumophila). Among these effectors, members of the SidE family (SidEs) regulate several cellular processes through a unique phosphoribosyl ubiquitination mechanism mediated by another effector, SidJ. Host-cell calmodulin (CaM) activates SidJ to glutamylate the SidEs of ubiquitin (Ub) ligases and to make a balanced Ub ligase activity. Given the central role of SidJ in this regulatory process, studying the nature of evolution of sidJ is important to understand the virulence of L. pneumophila and the interaction between the bacteria and its hosts. By studying sidJ from a large number of L. pneumophila strains and using various molecular evolution algorithms, we demonstrated that intragenic recombination drove the evolution of sidJ and contributed to sidJ diversification. Additionally, we showed that four codons of sidJ which are located in the N-terminal (NTD) (codons 58 and 200) and C-terminal (CTD) (codons 868 and 869) domains, but not in the kinase domain (KD) had been subjected to strong positive selection pressure, and variable mutation profiles of these codons were identified. Protein structural modeling of SidJ provided possible explanations for these mutations. Codons 868 and 869 mutations might engage in regulating the interactions of SidJ with CaM through hydrogen bonds and affect the CaM docking to SidJ. Mutation in codon 58 of SidJ might affect the distribution of main-chain atoms that are associated with the interaction with CaM. In contrast, mutations in codon 200 might influence the α-helix stability in the NTD. These mutations might be important to balance Ub ligase activity for different L. pneumophila hosts. This study first reported that intragenic recombination and positive Darwinian selection both shaped the genetic plasticity of sidJ, contributing to a deeper understanding of the adaptive mechanisms of this intracellular bacterium to different hosts.
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Affiliation(s)
- Xiao-Yong Zhan
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Jin-Lei Yang
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Xuefu Zhou
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yi-Chao Qian
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Ke Huang
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Honghua Sun
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Huacheng Wang
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yang Leng
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Bihui Huang
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yulong He
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
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Sun J, Wang X, Lin H, Wan L, Chen J, Yang X, Li D, Zhang Y, He X, Wang B, Dong M, Zhong H, Wei C. Shigella escapes lysosomal degradation through inactivation of Rab31 by IpaH4.5. J Med Microbiol 2021; 70. [PMID: 34296983 DOI: 10.1099/jmm.0.001382] [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: 11/18/2022] Open
Abstract
Introduction. Shigella flexneri is an intracellular bacterial pathogen that utilizes a type III secretion apparatus to inject effector proteins into host cells.Hypothesis/Gap Statement. The T3SS effector IpaH4.5 is important for the virulence of Shigella.Aim. This study aimed to elucidate the molecular mechanism and host target of the IpaH4.5 as well as its roles in S. flexneri infection.Methodology. The GAP assay was used to identify substrate Rab GTPases of IpaH4.5. A coimmunoprecipitation assay was applied to identify the interaction of Rab GTPases with IpaH4.5. A confocal microscopy analysis was used to assess the effects of IpaH4.5 on mannose 6-phosphate receptor (MPR) trafficking. To identify the effects of IpaH4.5 GAP activity on the activity of lysosomal cathepsin B, the Magic Red-RR assay was used. Finally, the intracellular persistence assay was used to identify IpaH4.5 GAP activity in S. flexneri intracellular growth.Results. We found that the effector IpaH4.5 disrupts MPR trafficking and lysosomal function, thereby counteracting host lysosomal degradation. IpaH4.5 harbours TBC-like dual-finger motifs and exhibits potent RabGAP activities towards Rab31. IpaH4.5 disrupts the transport of the cation-dependent mannose 6-phosphate receptor (CD-MPR) from the Golgi to the endosome by targeting Rab31, thereby attenuating lysosomal function. As a result, the intracellular persistence of S. flexneri requires IpaH4.5 TBC-like GAP activity to mediate bacterial escape from host lysosome-mediated elimination.Conclusion. We identified an unknown function of IpaH4.5 and its potential role in S. flexneri infection.
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Affiliation(s)
- Jin Sun
- Basic Medical College, Qingdao University, Qingdao, PR China.,Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Xiaolin Wang
- Basic Medical College, Qingdao University, Qingdao, PR China.,Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Haotian Lin
- Basic Medical College, Qingdao University, Qingdao, PR China.,Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Luming Wan
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Ji Chen
- Basic Medical College, Qingdao University, Qingdao, PR China
| | - Xiaopan Yang
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Dongyu Li
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Yanhong Zhang
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Xiang He
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Bin Wang
- Basic Medical College, Qingdao University, Qingdao, PR China
| | - Mingxin Dong
- Basic Medical College, Qingdao University, Qingdao, PR China
| | - Hui Zhong
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
| | - Congwen Wei
- Beijing Institute of Biotechnology, Academy of Military Medical Sciences (AMMS), Beijing, PR China
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Effectors of the Stenotrophomonas maltophilia Type IV Secretion System Mediate Killing of Clinical Isolates of Pseudomonas aeruginosa. mBio 2021; 12:e0150221. [PMID: 34182776 PMCID: PMC8262851 DOI: 10.1128/mbio.01502-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Previously, we documented that Stenotrophomonas maltophilia encodes a type IV secretion system (T4SS) that allows the organism to kill, in contact-dependent fashion, heterologous bacteria, including wild-type Pseudomonas aeruginosa. Bioinformatic screens based largely on the presence of both a C-terminal consensus sequence and an adjacent gene encoding a cognate immunity protein identified 13 potential antibacterial effectors, most of which were highly conserved among sequenced strains of S. maltophilia. The immunity proteins of two of these proved especially capable of protecting P. aeruginosa and Escherichia coli against attack from the Stenotrophomonas T4SS. In turn, S. maltophilia mutants lacking the putative effectors RS14245 and RS14255 were impaired for killing not only laboratory E. coli but clinical isolates of P. aeruginosa, including ones isolated from the lungs of cystic fibrosis patients. That complemented mutants behaved as wild type did confirmed that RS14245 and RS14255 are required for the bactericidal activity of the S. maltophilia T4SS. Moreover, a mutant lacking both of these proteins was as impaired as a mutant lacking the T4SS apparatus, indicating that RS14245 and RS14255 account for (nearly) all of the bactericidal effects seen. Utilizing an interbacterial protein translocation assay, we determined that RS14245 and RS14255 are bona fide substrates of the T4SS, a result confirmed by examination of mutants lacking both the T4SS and the individual effectors. Delivery of the cloned 14245 protein (alone) into the periplasm resulted in the killing of target bacteria, indicating that this effector, a putative lipase, is both necessary and sufficient for bactericidal activity.
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Anand IS, Choi W, Isberg RR. Components of the endocytic and recycling trafficking pathways interfere with the integrity of the Legionella-containing vacuole. Cell Microbiol 2021; 22:e13151. [PMID: 32096265 PMCID: PMC7154685 DOI: 10.1111/cmi.13151] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/10/2019] [Accepted: 12/03/2019] [Indexed: 12/27/2022]
Abstract
Legionella pneumophila requires the Dot/Icm translocation system to replicate in a vacuolar compartment within host cells. Strains lacking the translocated substrate SdhA form a permeable vacuole during residence in the host cell, exposing bacteria to the host cytoplasm. In primary macrophages, mutants are defective for intracellular growth, with a pyroptotic cell death response mounted due to bacterial exposure to the cytosol. To understand how SdhA maintains vacuole integrity during intracellular growth, we performed high-throughput RNAi screens against host membrane trafficking genes to identify factors that antagonise vacuole integrity in the absence of SdhA. Depletion of host proteins involved in endocytic uptake and recycling resulted in enhanced intracellular growth and lower levels of permeable vacuoles surrounding the ΔsdhA mutant. Of interest were three different Rab GTPases involved in these processes: Rab11b, Rab8b and Rab5 isoforms, that when depleted resulted in enhanced vacuole integrity surrounding the sdhA mutant. Proteins regulated by these Rabs are responsible for interfering with proper vacuole membrane maintenance, as depletion of the downstream effectors EEA1, Rab11FIP1, or VAMP3 rescued vacuole integrity and intracellular growth of the sdhA mutant. To test the model that specific vesicular components associated with these effectors could act to destabilise the replication vacuole, EEA1 and Rab11FIP1 showed increased density about the sdhA mutant vacuole compared with the wild type (WT) vacuole. Depletion of Rab5 isoforms or Rab11b reduced this aberrant redistribution. These findings are consistent with SdhA interfering with both endocytic and recycling membrane trafficking events that act to destabilise vacuole integrity during infection.
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Affiliation(s)
- Ila S Anand
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Wonyoung Choi
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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The vacuole guard hypothesis: how intravacuolar pathogens fight to maintain the integrity of their beloved home. Curr Opin Microbiol 2020; 54:51-58. [PMID: 32044688 DOI: 10.1016/j.mib.2020.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/09/2020] [Indexed: 12/16/2022]
Abstract
Intravacuolar bacterial pathogens establish intracellular niches by constructing membrane-encompassed compartments. The vacuoles surrounding the bacteria are remarkably stable, facilitating microbial replication and preventing exposure to host cytoplasmically localized innate immune sensing mechanisms. To maintain integrity of the membrane compartment, the pathogen is armed with defensive weapons that prevent loss of vacuole integrity and potential exposure to host innate signaling. In some cases, the microbial components that maintain vacuolar integrity have been identified, but the basis for why the compartment degrades in their absence is unclear. In this review, we point out that lessons from the microbial-programmed degradation of the vacuole by the cytoplasmically localized Shigella flexneri provide crucial insights into how degradation of pathogen vacuoles occurs. We propose that in the absence of bacterial-encoded guard proteins, aberrant trafficking of host membrane-associated components results in a dysfunctional pathogen compartment. As a consequence, the vacuole is poisoned and replication is terminated.
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