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Giménez A, Del Giudice MG, López PV, Guaimas F, Sámano-Sánchez H, Gibson TJ, Chemes LB, Arregui CO, Ugalde JE, Czibener C. Brucella NpeA is a secreted Type IV effector containing an N-WASP-binding short linear motif that promotes niche formation. mBio 2024; 15:e0072624. [PMID: 38847540 PMCID: PMC11253601 DOI: 10.1128/mbio.00726-24] [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: 03/11/2024] [Accepted: 05/01/2024] [Indexed: 07/18/2024] Open
Abstract
The modulation of actin polymerization is a common theme among microbial pathogens. Even though microorganisms show a wide repertoire of strategies to subvert the activity of actin, most of them converge in the ones that activate nucleating factors, such as the Arp2/3 complex. Brucella spp. are intracellular pathogens capable of establishing chronic infections in their hosts. The ability to subvert the host cell response is dependent on the capacity of the bacterium to attach, invade, avoid degradation in the phagocytic compartment, replicate in an endoplasmic reticulum-derived compartment and egress. Even though a significant number of mechanisms deployed by Brucella in these different phases have been identified and characterized, none of them have been described to target actin as a cellular component. In this manuscript, we describe the identification of a novel virulence factor (NpeA) that promotes niche formation. NpeA harbors a short linear motif (SLiM) present within an amphipathic alpha helix that has been described to bind the GTPase-binding domain (GBD) of N-WASP and stabilizes the autoinhibited state. Our results show that NpeA is secreted in a Type IV secretion system-dependent manner and that deletion of the gene diminishes the intracellular replication capacity of the bacterium. In vitro and ex vivo experiments demonstrate that NpeA binds N-WASP and that the short linear motif is required for the biological activity of the protein.IMPORTANCEThe modulation of actin-binding effectors that regulate the activity of this fundamental cellular protein is a common theme among bacterial pathogens. The neural Wiskott-Aldrich syndrome protein (N-WASP) is a protein that several pathogens target to hijack actin dynamics. The highly adapted intracellular bacterium Brucella has evolved a wide repertoire of virulence factors that modulate many activities of the host cell to establish successful intracellular replication niches, but, to date, no effector proteins have been implicated in the modulation of actin dynamics. We present here the identification of a virulence factor that harbors a short linear motif (SLiM) present within an amphipathic alpha helix that has been described to bind the GTPase-binding domain (GBD) of N-WASP stabilizing its autoinhibited state. We demonstrate that this protein is a Type IV secretion effector that targets N-WASP-promoting intracellular survival and niche formation.
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Affiliation(s)
- Agostina Giménez
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Mariela G. Del Giudice
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Paula V. López
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Francisco Guaimas
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Hugo Sámano-Sánchez
- Zhejiang University School of Medicine, International Campus, Zhejiang University, Haining, China
- Biomedical Sciences, Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Toby J. Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Lucía B. Chemes
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Carlos O. Arregui
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Juan E. Ugalde
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Cecilia Czibener
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
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Raab JE, Hamilton DJ, Harju TB, Huynh TN, Russo BC. Pushing boundaries: mechanisms enabling bacterial pathogens to spread between cells. Infect Immun 2024:e0052423. [PMID: 38661369 DOI: 10.1128/iai.00524-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
For multiple intracellular bacterial pathogens, the ability to spread directly into adjacent epithelial cells is an essential step for disease in humans. For pathogens such as Shigella, Listeria, Rickettsia, and Burkholderia, this intercellular movement frequently requires the pathogens to manipulate the host actin cytoskeleton and deform the plasma membrane into structures known as protrusions, which extend into neighboring cells. The protrusion is then typically resolved into a double-membrane vacuole (DMV) from which the pathogen quickly escapes into the cytosol, where additional rounds of intercellular spread occur. Significant progress over the last few years has begun to define the mechanisms by which intracellular bacterial pathogens spread. This review highlights the interactions of bacterial and host factors that drive mechanisms required for intercellular spread with a focus on how protrusion structures form and resolve.
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Affiliation(s)
- Julie E Raab
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Desmond J Hamilton
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Tucker B Harju
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Thao N Huynh
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
| | - Brian C Russo
- Department of Immunology and Microbiology, School of Medicine, University of Colorado-Anschutz Medical Campus, Denver, Colorado, USA
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3
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Qin J, Hong Y, Morona R, Totsika M. Cysteine-Dependent Conformational Heterogeneity of Shigella flexneri Autotransporter IcsA and Implications of Its Function. Microbiol Spectr 2022; 10:e0341022. [PMID: 36374106 PMCID: PMC9769942 DOI: 10.1128/spectrum.03410-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/30/2022] [Indexed: 11/16/2022] Open
Abstract
Shigella IcsA is a versatile surface virulence factor required for early and late pathogenesis stages extracellularly and intracellularly. Despite IcsA serving as a model Type V secretion system (T5SS) autotransporter to study host-pathogen interactions, its detailed molecular architecture is poorly understood. Recently, IcsA was found to switch to a different conformation for its adhesin activity upon sensing the host stimuli by Shigella Type III secretion system (T3SS). Here, we reported that the single cysteine residue (C130) near the N terminus of the IcsA passenger had a role in IcsA adhesin activity. We also showed that the IcsA passenger (IcsAp) existed in multiple conformations, and the conformation populations were influenced by a central pair of cysteine residues (C375 and C379), which was not previously reported for any Type V autotransporter passengers. Disruption of either or both central cysteine residues altered the exposure of IcsA epitopes to polyclonal anti-IcsA antibodies previously shown to block Shigella adherence, yet without loss of IcsA intracellular functions in actin-based motility (ABM). Anti-IcsA antibody reactivity was restored when the IcsA-paired cysteine substitution mutants were expressed in an ΔipaD background with a constitutively active T3SS, highlighting an interplay between T3SS and T5SS. The work here uncovered a novel molecular switch empowered by a centrally localized, short-spaced cysteine pair in the Type V autotransporter IcsA that ensured conformational heterogeneity to aid IcsA evasion of host immunity. IMPORTANCE Shigella species are the leading cause of diarrheal-related death globally by causing bacillary dysentery. The surface virulence factor IcsA, which is essential for Shigella pathogenesis, is a unique multifunctional autotransporter that is responsible for cell adhesion, and actin-based motility, yet detailed mechanistic understanding is lacking. Here, we showed that the three cysteine residues in IcsA contributed to the protein's distinct functions. The N-terminal cysteine residue within the IcsA passenger domain played a role in adhesin function, while a centrally localized cysteine pair provided conformational heterogeneity that resulted in IcsA molecules with different reactivity to adhesion-blocking anti-IcsA antibodies. In synergy with the Type III secretion system, this molecular switch preserved biological function in distinct IcsA conformations for cell adhesion, actin-based motility, and autophagy escape, providing a potential strategy by which Shigella evades host immunity and targets this essential virulence factor.
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Affiliation(s)
- Jilong Qin
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Yaoqin Hong
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Renato Morona
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Makrina Totsika
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
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Huang D, Luo J, OuYang X, Song L. Subversion of host cell signaling: The arsenal of Rickettsial species. Front Cell Infect Microbiol 2022; 12:995933. [PMID: 36389139 PMCID: PMC9659576 DOI: 10.3389/fcimb.2022.995933] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 10/04/2022] [Indexed: 10/10/2023] Open
Abstract
Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and typhi group are major members of the genus Rickettsia. Rickettsial species from the two groups subvert diverse host cellular processes, including membrane dynamics, actin cytoskeleton dynamics, phosphoinositide metabolism, intracellular trafficking, and immune defense, to promote their host colonization and intercellular transmission through secreted effectors (virulence factors). However, lineage-specific rickettsiae have exploited divergent strategies to accomplish such challenging tasks and these elaborated strategies focus on distinct host cell processes. In the present review, we summarized current understandings of how different rickettsial species employ their effectors' arsenal to affect host cellular processes in order to promote their own replication or to avoid destruction.
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Affiliation(s)
- Dan Huang
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Jingjing Luo
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Xuan OuYang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lei Song
- Department of Respiratory Medicine, Center of Pathogen Biology and Infectious Disease, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
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Hill NS, Welch MD. A glycine-rich PE_PGRS protein governs mycobacterial actin-based motility. Nat Commun 2022; 13:3608. [PMID: 35750685 PMCID: PMC9232537 DOI: 10.1038/s41467-022-31333-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 06/14/2022] [Indexed: 11/09/2022] Open
Abstract
Many key insights into actin regulation have been derived through examining how microbial pathogens intercept the actin cytoskeleton during infection. Mycobacterium marinum, a close relative of the human pathogen Mycobacterium tuberculosis, polymerizes host actin at the bacterial surface to drive intracellular movement and cell-to-cell spread during infection. However, the mycobacterial factor that commandeers actin polymerization has remained elusive. Here, we report the identification and characterization of the M. marinum actin-based motility factor designated mycobacterial intracellular rockets A (MirA), which is a member of the glycine-rich PE_PGRS protein family. MirA contains an amphipathic helix to anchor into the mycobacterial outer membrane and, surprisingly, also the surface of host lipid droplet organelles. MirA directly binds to and activates the host protein N-WASP to stimulate actin polymerization through the Arp2/3 complex, directing both bacterial and lipid droplet actin-based motility. MirA is dissimilar to known N-WASP activating ligands and may represent a new class of microbial and host actin regulator. Additionally, the MirA-N-WASP interaction represents a model to understand how the enigmatic PE_PGRS proteins contribute to mycobacterial pathogenesis.
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Affiliation(s)
- Norbert S Hill
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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Kramer DA, Piper HK, Chen B. WASP family proteins: Molecular mechanisms and implications in human disease. Eur J Cell Biol 2022; 101:151244. [PMID: 35667337 PMCID: PMC9357188 DOI: 10.1016/j.ejcb.2022.151244] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 02/08/2023] Open
Abstract
Proteins of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in regulating actin cytoskeletal dynamics in a wide range of cellular processes. Genetic mutations or misregulation of these proteins are tightly associated with many diseases. The WASP-family proteins act by transmitting various upstream signals to their conserved WH2-Central-Acidic (WCA) peptide sequence at the C-terminus, which in turn binds to the Arp2/3 complex to stimulate the formation of branched actin networks at membranes. Despite this common feature, the regulatory mechanisms and cellular functions of distinct WASP-family proteins are very different. Here, we summarize and clarify our current understanding of WASP-family proteins and how disruption of their functions is related to human disease.
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Affiliation(s)
- Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Hannah K Piper
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA.
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7
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Kutsch M, Coers J. Human guanylate binding proteins: nanomachines orchestrating host defense. FEBS J 2021; 288:5826-5849. [PMID: 33314740 PMCID: PMC8196077 DOI: 10.1111/febs.15662] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/27/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
Disease-causing microorganisms not only breach anatomical barriers and invade tissues but also frequently enter host cells, nutrient-enriched environments amenable to support parasitic microbial growth. Protection from many infectious diseases is therefore reliant on the ability of individual host cells to combat intracellular infections through the execution of cell-autonomous defense programs. Central players in human cell-autonomous immunity are members of the family of dynamin-related guanylate binding proteins (GBPs). The importance of these interferon-inducible GTPases in host defense to viral, bacterial, and protozoan pathogens has been established for some time; only recently, cell biological and biochemical studies that largely focused on the prenylated paralogs GBP1, GBP2, and GBP5 have provided us with robust molecular frameworks for GBP-mediated immunity. Specifically, the recent characterization of GBP1 as a bona fide pattern recognition receptor for bacterial lipopolysaccharide (LPS) disrupting the integrity of bacterial outer membranes through LPS aggregation, the discovery of a link between hydrolysis-induced GMP production by GBP1 and inflammasome activation, and the classification of GBP2 and GBP5 as inhibitors of viral envelope glycoprotein processing via suppression of the host endoprotease furin have paved the way for a vastly improved conceptual understanding of the molecular mechanisms by which GBP nanomachines execute cell-autonomous immunity. The herein discussed models incorporate our current knowledge of the antimicrobial, proinflammatory, and biochemical properties of human GBPs and thereby provide testable hypotheses that will guide future studies into the intricacies of GBP-controlled host defense and their role in human disease.
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Affiliation(s)
- Miriam Kutsch
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 22710, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 22710, USA
- Department of Immunology, Duke University Medical Center, Durham, North Carolina 22710, USA
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8
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Kutsch M, González-Prieto C, Lesser CF, Coers J. The GBP1 microcapsule interferes with IcsA-dependent septin cage assembly around Shigella flexneri. Pathog Dis 2021; 79:6246431. [PMID: 33885766 DOI: 10.1093/femspd/ftab023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/08/2021] [Indexed: 12/20/2022] Open
Abstract
Many cytosolic bacterial pathogens hijack the host actin polymerization machinery to form actin tails that promote direct cell-to-cell spread, enabling these pathogens to avoid extracellular immune defenses. However, these pathogens are still susceptible to intracellular cell-autonomous immune responses that restrict bacterial actin-based motility. Two classes of cytosolic antimotility factors, septins and guanylate-binding proteins (GBPs), have recently been established to block actin tail formation by the human-adapted bacterial pathogen Shigella flexneri. Both septin cages and GBP1 microcapsules restrict S. flexneri cell-to-cell spread by blocking S. flexneri actin-based motility. While septins assemble into cage-like structures around immobile S. flexneri, GBP1 forms microcapsules around both motile and immobile bacteria. The interplay between these two defense programs remains elusive. Here, we demonstrate that GBP1 microcapsules block septin cage assembly, likely by interfering with the function of S. flexneri IcsA, the outer membrane protein that promotes actin-based motility, as this protein is required for septin cage formation. However, S. flexneri that escape from GBP1 microcapsules via the activity of IpaH9.8, a type III secreted effector that promotes the degradation of GBPs, are often captured within septin cages. Thus, our studies reveal how septin cages and GBP1 microcapsules represent complementary host cell antimotility strategies.
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Affiliation(s)
- Miriam Kutsch
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Coral González-Prieto
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.,Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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Faris R, McCullough A, Andersen SE, Moninger TO, Weber MM. The Chlamydia trachomatis secreted effector TmeA hijacks the N-WASP-ARP2/3 actin remodeling axis to facilitate cellular invasion. PLoS Pathog 2020; 16:e1008878. [PMID: 32946535 PMCID: PMC7526919 DOI: 10.1371/journal.ppat.1008878] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/30/2020] [Accepted: 08/12/2020] [Indexed: 11/19/2022] Open
Abstract
As an obligate intracellular pathogen, host cell invasion is paramount to Chlamydia trachomatis proliferation. While the mechanistic underpinnings of this essential process remain ill-defined, it is predicted to involve delivery of prepackaged effector proteins into the host cell that trigger plasma membrane remodeling and cytoskeletal reorganization. The secreted effector proteins TmeA and TarP, have risen to prominence as putative key regulators of cellular invasion and bacterial pathogenesis. Although several studies have begun to unravel molecular details underlying the putative function of TarP, the physiological function of TmeA during host cell invasion is unknown. Here, we show that TmeA employs molecular mimicry to bind to the GTPase binding domain of N-WASP, which results in recruitment of the actin branching ARP2/3 complex to the site of chlamydial entry. Electron microscopy revealed that TmeA mutants are deficient in filopodia capture, suggesting that TmeA/N-WASP interactions ultimately modulate host cell plasma membrane remodeling events necessary for chlamydial entry. Importantly, while both TmeA and TarP are necessary for effective host cell invasion, we show that these effectors target distinct pathways that ultimately converge on activation of the ARP2/3 complex. In line with this observation, we show that a double mutant suffers from a severe entry defect nearly identical to that observed when ARP3 is chemically inhibited or knocked down. Collectively, our study highlights both TmeA and TarP as essential regulators of chlamydial invasion that modulate the ARP2/3 complex through distinct signaling platforms, resulting in plasma membrane remodeling events that are essential for pathogen uptake.
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Affiliation(s)
- Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Alix McCullough
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Shelby E. Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Thomas O. Moninger
- Central Microscopy Research Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Mary M. Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
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Evolutionary Perspectives on the Moonlighting Functions of Bacterial Factors That Support Actin-Based Motility. mBio 2019; 10:mBio.01520-19. [PMID: 31455648 PMCID: PMC6712393 DOI: 10.1128/mbio.01520-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Various bacterial pathogens display an intracellular lifestyle and spread from cell to cell through actin-based motility (ABM). ABM requires actin polymerization at the bacterial pole and is mediated by the expression of bacterial factors that hijack the host cell actin nucleation machinery or exhibit intrinsic actin nucleation properties. Various bacterial pathogens display an intracellular lifestyle and spread from cell to cell through actin-based motility (ABM). ABM requires actin polymerization at the bacterial pole and is mediated by the expression of bacterial factors that hijack the host cell actin nucleation machinery or exhibit intrinsic actin nucleation properties. It is increasingly recognized that bacterial ABM factors, in addition to having a crucial task during the intracellular phase of infection, display “moonlighting” adhesin functions, such as bacterial aggregation, biofilm formation, and host cell adhesion/invasion. Here, we review our current knowledge of ABM factors and their additional functions, and we propose that intracellular ABM functions have evolved from ancestral, extracellular adhesin functions.
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De Souza Santos M, Orth K. The Role of the Type III Secretion System in the Intracellular Lifestyle of Enteric Pathogens. Microbiol Spectr 2019; 7:10.1128/microbiolspec.bai-0008-2019. [PMID: 31152523 PMCID: PMC11026088 DOI: 10.1128/microbiolspec.bai-0008-2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Indexed: 11/20/2022] Open
Abstract
Several pathogens have evolved to infect host cells from within, which requires subversion of many host intracellular processes. In the case of Gram-negative pathogenic bacteria, adaptation to an intracellular life cycle relies largely on the activity of type III secretion systems (T3SSs), an apparatus used to deliver effector proteins into the host cell, from where these effectors regulate important cellular functions such as vesicular trafficking, cytoskeleton reorganization, and the innate immune response. Each bacterium is equipped with a unique suite of these T3SS effectors, which aid in the development of an individual intracellular lifestyle for their respective pathogens. Some bacteria adapt to reside and propagate within a customized vacuole, while others establish a replicative niche in the host cytosol. In this article, we review the mechanisms by which T3SS effectors contribute to these different lifestyles. To illustrate the formation of a vacuolar and a cytosolic lifestyle, we discuss the intracellular habitats of the enteric pathogens Salmonella enterica serovar Typhimurium and Shigella flexneri, respectively. These represent well-characterized systems that function as informative models to contribute to our understanding of T3SS-dependent subversion of intracellular processes. Additionally, we present Vibrio parahaemolyticus, another enteric Gram-negative pathogen, as an emerging model for future studies of the cytosolic lifestyle.
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Affiliation(s)
- Marcela De Souza Santos
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biochemistry and
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
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12
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Dorman MJ, Dorman CJ. Regulatory Hierarchies Controlling Virulence Gene Expression in Shigella flexneri and Vibrio cholerae. Front Microbiol 2018; 9:2686. [PMID: 30473684 PMCID: PMC6237886 DOI: 10.3389/fmicb.2018.02686] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
Gram-negative enteropathogenic bacteria use a variety of strategies to cause disease in the human host and gene regulation in some form is typically a part of the strategy. This article will compare the toxin-based infection strategy used by the non-invasive pathogen Vibrio cholerae, the etiological agent in human cholera, with the invasive approach used by Shigella flexneri, the cause of bacillary dysentery. Despite the differences in the mechanisms by which the two pathogens cause disease, they use environmentally-responsive regulatory hierarchies to control the expression of genes that have some features, and even some components, in common. The involvement of AraC-like transcription factors, the integration host factor, the Factor for inversion stimulation, small regulatory RNAs, the RNA chaperone Hfq, horizontal gene transfer, variable DNA topology and the need to overcome the pervasive silencing of transcription by H-NS of horizontally acquired genes are all shared features. A comparison of the regulatory hierarchies in these two pathogens illustrates some striking cross-species similarities and differences among mechanisms coordinating virulence gene expression. S. flexneri, with its low infectious dose, appears to use a strategy that is centered on the individual bacterial cell, whereas V. cholerae, with a community-based, quorum-dependent approach and an infectious dose that is several orders of magnitude higher, seems to rely more on the actions of a bacterial collective.
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Affiliation(s)
- Matthew J Dorman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Charles J Dorman
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
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Wandel MP, Pathe C, Werner EI, Ellison CJ, Boyle KB, von der Malsburg A, Rohde J, Randow F. GBPs Inhibit Motility of Shigella flexneri but Are Targeted for Degradation by the Bacterial Ubiquitin Ligase IpaH9.8. Cell Host Microbe 2018; 22:507-518.e5. [PMID: 29024643 PMCID: PMC5644667 DOI: 10.1016/j.chom.2017.09.007] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/11/2017] [Accepted: 09/18/2017] [Indexed: 01/04/2023]
Abstract
Interferon exposure boosts cell-autonomous immunity for more efficient pathogen control. But how interferon-enhanced immunity protects the cytosol against bacteria and how professionally cytosol-dwelling bacteria avoid clearance are insufficiently understood. Here we demonstrate that the interferon-induced GTPase family of guanylate-binding proteins (GBPs) coats Shigella flexneri in a hierarchical manner reliant on GBP1. GBPs inhibit actin-dependent motility and cell-to-cell spread of bacteria but are antagonized by IpaH9.8, a bacterial ubiquitin ligase secreted into the host cytosol. IpaH9.8 ubiquitylates GBP1, GBP2, and GBP4 to cause the proteasome-dependent destruction of existing GBP coats. This ubiquitin coating of Shigella favors the pathogen as it liberates bacteria from GBP encapsulation to resume actin-mediated motility and cell-to-cell spread. We conclude that an important function of GBP recruitment to S. flexneri is to prevent the spread of infection to neighboring cells while IpaH9.8 helps bacterial propagation by counteracting GBP-dependent cell-autonomous immunity. Guanylate-binding proteins (GBPs) coat S. flexneri in a GBP1-dependent manner GBP coats antagonize bacterial actin-dependent motility and cell-to-cell spreading IpaH9.8, a bacterial E3 ubiquitin ligase, targets GBPs for degradation IpaH9.8 re-establishes bacterial motility and cell-to-cell spread
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Affiliation(s)
- Michal P Wandel
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Claudio Pathe
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Emma I Werner
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Cara J Ellison
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Keith B Boyle
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alexander von der Malsburg
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - John Rohde
- Department of Microbiology and Immunology, Dalhousie University Halifax, Halifax, NS B3H 4R2, Canada
| | - Felix Randow
- MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK; University of Cambridge, Department of Medicine, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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Recent developments in small-angle X-ray scattering and hybrid method approaches for biomacromolecular solutions. Emerg Top Life Sci 2018; 2:69-79. [PMID: 33525782 DOI: 10.1042/etls20170138] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 01/05/2023]
Abstract
Small-angle X-ray scattering (SAXS) has become a streamline method to characterize biological macromolecules, from small peptides to supramolecular complexes, in near-native solutions. Modern SAXS requires limited amounts of purified material, without the need for labelling, crystallization, or freezing. Dedicated beamlines at modern synchrotron sources yield high-quality data within or below several milliseconds of exposure time and are highly automated, allowing for rapid structural screening under different solutions and ambient conditions but also for time-resolved studies of biological processes. The advanced data analysis methods allow one to meaningfully interpret the scattering data from monodisperse systems, from transient complexes as well as flexible and heterogeneous systems in terms of structural models. Especially powerful are hybrid approaches utilizing SAXS with high-resolution structural techniques, but also with biochemical, biophysical, and computational methods. Here, we review the recent developments in the experimental SAXS practice and in analysis methods with a specific focus on the joint use of SAXS with complementary methods.
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