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Zhu K, Guo X, Chandrasekaran A, Miao X, Rangamani P, Zhao W, Miao Y. Membrane curvature catalyzes actin nucleation through nano-scale condensation of N-WASP-FBP17. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591054. [PMID: 38712166 PMCID: PMC11071460 DOI: 10.1101/2024.04.25.591054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Actin remodeling is spatiotemporally regulated by surface topographical cues on the membrane for signaling across diverse biological processes. Yet, the mechanism dynamic membrane curvature prompts quick actin cytoskeletal changes in signaling remain elusive. Leveraging the precision of nanolithography to control membrane curvature, we reconstructed catalytic reactions from the detection of nano-scale curvature by sensing molecules to the initiation of actin polymerization, which is challenging to study quantitatively in living cells. We show that this process occurs via topographical signal-triggered condensation and activation of the actin nucleation-promoting factor (NPF), Neuronal Wiskott-Aldrich Syndrome protein (N-WASP), which is orchestrated by curvature-sensing BAR-domain protein FBP17. Such N-WASP activation is fine-tuned by optimizing FBP17 to N-WASP stoichiometry over different curvature radii, allowing a curvature-guided macromolecular assembly pattern for polymerizing actin network locally. Our findings shed light on the intricate relationship between changes in curvature and actin remodeling via spatiotemporal regulation of NPF/BAR complex condensation.
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2
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Sanchez L, Lensen A, Connor MG, Hamon M, Enninga J, Valenzuela C. Shigella generates distinct IAM subpopulations during epithelial cell invasion to promote efficient intracellular niche formation. Eur J Cell Biol 2024; 103:151381. [PMID: 38183814 DOI: 10.1016/j.ejcb.2023.151381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 12/20/2023] [Accepted: 12/24/2023] [Indexed: 01/08/2024] Open
Abstract
The facultative intracellular pathogen Shigella flexneri invades non-phagocytic epithelial gut cells. Through a syringe-like apparatus called type 3 secretion system, it injects effector proteins into the host cell triggering actin rearrangements leading to its uptake within a tight vacuole, termed the bacterial-containing vacuole (BCV). Simultaneously, Shigella induces the formation of large vesicles around the entry site, which we refer to as infection-associated macropinosomes (IAMs). After entry, Shigella ruptures the BCV and escapes into the host cytosol by disassembling the BCV remnants. Previously, IAM formation has been shown to be required for efficient BCV escape, but the molecular events associated with BCV disassembly have remained unclear. To identify host components required for BCV disassembly, we performed a microscopy-based screen to monitor the recruitment of BAR domain-containing proteins, which are a family of host proteins involved in membrane shaping and sensing (e.g. endocytosis and recycling) during Shigella epithelial cell invasion. We identified endosomal recycling BAR protein Sorting Nexin-8 (SNX8) localized to IAMs in a PI(3)P-dependent manner before BCV disassembly. At least two distinct IAM subpopulations around the BCV were found, either being recycled back to cellular compartments such as the plasma membrane or transitioning to become RAB11A positive "contact-IAMs" involved in promoting BCV rupture. The IAM subpopulation duality was marked by the exclusive recruitment of either SNX8 or RAB11A. Hindering PI(3)P production at the IAMs led to an inhibition of SNX8 recruitment at these compartments and delayed both, the step of BCV rupture time and successful BCV disassembly. Finally, siRNA depletion of SNX8 accelerated BCV rupture and unpeeling of BCV remnants, indicating that SNX8 is involved in controlling the timing of the cytosolic release. Overall, our work sheds light on how Shigella establishes its intracellular niche through the subversion of a specific set of IAMs.
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Affiliation(s)
- Lisa Sanchez
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Arthur Lensen
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Michael G Connor
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Mélanie Hamon
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Jost Enninga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
| | - Camila Valenzuela
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
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Valenzuela-Valderas KN, Farrashzadeh E, Chang YY, Shi Y, Raudonis R, Leung BM, Rohde JR, Enninga J, Cheng Z. RACK1 promotes Shigella flexneri actin-mediated invasion, motility, and cell-to-cell spreading. iScience 2023; 26:108216. [PMID: 37953961 PMCID: PMC10637933 DOI: 10.1016/j.isci.2023.108216] [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: 04/28/2023] [Revised: 08/19/2023] [Accepted: 10/11/2023] [Indexed: 11/14/2023] Open
Abstract
Shigella flexneri is an intracellular bacterium that hijacks the host actin cytoskeleton to invade and disseminate within the colonic epithelium. Shigella's virulence factors induce actin polymerization, leading to bacterial uptake, actin tail formation, actin-mediated motility, and cell-to-cell spreading. Many host factors involved in the Shigella-prompted actin rearrangements remain elusive. Here, we studied the role of a host protein receptor for activated C kinase 1 (RACK1) in actin cytoskeleton dynamics and Shigella infection. We used time-lapse imaging to demonstrate that RACK1 facilitates Shigella-induced actin cytoskeleton remodeling at multiple levels during infection of epithelial cells. Silencing RACK1 expression impaired Shigella-induced rapid polymerizing structures, reducing host cell invasion, bacterial motility, and cell-to-cell spreading. In uninfected cells, RACK1 silencing reduced jasplakinolide-mediated filamentous actin aggregate formation and negatively affected actin turnover in fast polymerizing structures, such as membrane ruffles. Our findings provide a role of RACK1 in actin cytoskeleton dynamics and Shigella infection.
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Affiliation(s)
| | - Elmira Farrashzadeh
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Yuen-Yan Chang
- Unité Dynamique des interactions hôtes-pathogènes, Institut Pasteur and CNRS UMR3691, Université de Paris-Cité, 75724 Paris, France
| | - Yunnuo Shi
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Renee Raudonis
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Brendan M. Leung
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - John R. Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jost Enninga
- Unité Dynamique des interactions hôtes-pathogènes, Institut Pasteur and CNRS UMR3691, Université de Paris-Cité, 75724 Paris, France
| | - Zhenyu Cheng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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4
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Grijmans BJM, van der Kooij SB, Varela M, Meijer AH. LAPped in Proof: LC3-Associated Phagocytosis and the Arms Race Against Bacterial Pathogens. Front Cell Infect Microbiol 2022; 11:809121. [PMID: 35047422 PMCID: PMC8762105 DOI: 10.3389/fcimb.2021.809121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/10/2021] [Indexed: 01/05/2023] Open
Abstract
Cells of the innate immune system continuously patrol the extracellular environment for potential microbial threats that are to be neutralized by phagocytosis and delivery to lysosomes. In addition, phagocytes employ autophagy as an innate immune mechanism against pathogens that succeed to escape the phagolysosomal pathway and invade the cytosol. In recent years, LC3-associated phagocytosis (LAP) has emerged as an intermediate between phagocytosis and autophagy. During LAP, phagocytes target extracellular microbes while using parts of the autophagic machinery to label the cargo-containing phagosomes for lysosomal degradation. LAP contributes greatly to host immunity against a multitude of bacterial pathogens. In the pursuit of survival, bacteria have developed elaborate strategies to disarm or circumvent the LAP process. In this review, we will outline the nature of the LAP mechanism and discuss recent insights into its interplay with bacterial pathogens.
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Affiliation(s)
| | | | - Monica Varela
- Institute of Biology Leiden, Leiden University, Leiden, Netherlands
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5
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Bajunaid W, Haidar-Ahmad N, Kottarampatel AH, Ourida Manigat F, Silué N, F. Tchagang C, Tomaro K, Campbell-Valois FX. The T3SS of Shigella: Expression, Structure, Function, and Role in Vacuole Escape. Microorganisms 2020; 8:microorganisms8121933. [PMID: 33291504 PMCID: PMC7762205 DOI: 10.3390/microorganisms8121933] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022] Open
Abstract
Shigella spp. are one of the leading causes of infectious diarrheal diseases. They are Escherichia coli pathovars that are characterized by the harboring of a large plasmid that encodes most virulence genes, including a type III secretion system (T3SS). The archetypal element of the T3SS is the injectisome, a syringe-like nanomachine composed of approximately 20 proteins, spanning both bacterial membranes and the cell wall, and topped with a needle. Upon contact of the tip of the needle with the plasma membrane, the injectisome secretes its protein substrates into host cells. Some of these substrates act as translocators or effectors whose functions are key to the invasion of the cytosol and the cell-to-cell spread characterizing the lifestyle of Shigella spp. Here, we review the structure, assembly, function, and methods to measure the activity of the injectisome with a focus on Shigella, but complemented with data from other T3SS if required. We also present the regulatory cascade that controls the expression of T3SS genes in Shigella. Finally, we describe the function of translocators and effectors during cell-to-cell spread, particularly during escape from the vacuole, a key element of Shigella’s pathogenesis that has yet to reveal all of its secrets.
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Affiliation(s)
- Waad Bajunaid
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Nathaline Haidar-Ahmad
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Anwer Hasil Kottarampatel
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - France Ourida Manigat
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Navoun Silué
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Caetanie F. Tchagang
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Kyle Tomaro
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Correspondence:
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6
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Michard C, Yum LK, Agaisse H. WIPF2 promotesShigella flexneriactin‐based motility and cell‐to‐cell spread. Cell Microbiol 2019; 21:e13098. [DOI: 10.1111/cmi.13098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 08/08/2019] [Accepted: 08/10/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Céline Michard
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
| | - Lauren K. Yum
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
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7
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BAR domain proteins-a linkage between cellular membranes, signaling pathways, and the actin cytoskeleton. Biophys Rev 2018; 10:1587-1604. [PMID: 30456600 DOI: 10.1007/s12551-018-0467-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/17/2018] [Indexed: 12/23/2022] Open
Abstract
Actin filament assembly typically occurs in association with cellular membranes. A large number of proteins sit at the interface between actin networks and membranes, playing diverse roles such as initiation of actin polymerization, modulation of membrane curvature, and signaling. Bin/Amphiphysin/Rvs (BAR) domain proteins have been implicated in all of these functions. The BAR domain family of proteins comprises a diverse group of multi-functional effectors, characterized by their modular architecture. In addition to the membrane-curvature sensing/inducing BAR domain module, which also mediates antiparallel dimerization, most contain auxiliary domains implicated in protein-protein and/or protein-membrane interactions, including SH3, PX, PH, RhoGEF, and RhoGAP domains. The shape of the BAR domain itself varies, resulting in three major subfamilies: the classical crescent-shaped BAR, the more extended and less curved F-BAR, and the inverse curvature I-BAR subfamilies. Most members of this family have been implicated in cellular functions that require dynamic remodeling of the actin cytoskeleton, such as endocytosis, organelle trafficking, cell motility, and T-tubule biogenesis in muscle cells. Here, we review the structure and function of mammalian BAR domain proteins and the many ways in which they are interconnected with the actin cytoskeleton.
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8
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Flieger A, Frischknecht F, Häcker G, Hornef MW, Pradel G. Pathways of host cell exit by intracellular pathogens. MICROBIAL CELL 2018; 5:525-544. [PMID: 30533418 PMCID: PMC6282021 DOI: 10.15698/mic2018.12.659] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Host cell exit is a critical step in the life-cycle of intracellular pathogens, intimately linked to barrier penetration, tissue dissemination, inflammation, and pathogen transmission. Like cell invasion and intracellular survival, host cell exit represents a well-regulated program that has evolved during host-pathogen co-evolution and that relies on the dynamic and intricate interplay between multiple host and microbial factors. Three distinct pathways of host cell exit have been identified that are employed by three different taxa of intracellular pathogens, bacteria, fungi and protozoa, namely (i) the initiation of programmed cell death, (ii) the active breaching of host cellderived membranes, and (iii) the induced membrane-dependent exit without host cell lysis. Strikingly, an increasing number of studies show that the majority of intracellular pathogens utilize more than one of these strategies, dependent on life-cycle stage, environmental factors and/or host cell type. This review summarizes the diverse exit strategies of intracellular-living bacterial, fungal and protozoan pathogens and discusses the convergently evolved commonalities as well as system-specific variations thereof. Key microbial molecules involved in host cell exit are highlighted and discussed as potential targets for future interventional approaches.
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Affiliation(s)
- Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | | | - Georg Häcker
- Institute of Medical Microbiology and Hygiene, Medical Center - University of Freiburg, Germany
| | - Mathias W Hornef
- Institute of Medical Microbiology, RWTH Aachen University Hospital, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Biology II, RWTH Aachen University, Germany
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9
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Miller KA, Garza-Mayers AC, Leung Y, Goldberg MB. Identification of interactions among host and bacterial proteins and evaluation of their role early during Shigella flexneri infection. MICROBIOLOGY-SGM 2018; 164:540-550. [PMID: 29488864 DOI: 10.1099/mic.0.000637] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Shigella species cause diarrhoea by invading and spreading through the epithelial layer of the human colon. The infection triggers innate immune responses in the host that the bacterium combats by translocating into the host cell cytosol via a type 3 secretion system bacterial effector proteins that interfere with host processes. We previously demonstrated that interaction of the Shigella type 3 secreted effector protein IcsB with the host protein Toca-1 inhibits the innate immune response microtubule-associated protein light-chain 3 (LC3)-associated phagocytosis, and that IcsB interaction with Toca-1 is required for inhibition of this host response. Here, we show that Toca-1 in vitro precipitated not only IcsB, but also the type 3 secreted proteins OspC3, IpgD and IpaB. OspC3 and IpgD precipitation with Toca-1 was dependent on IcsB. Early during infection, most of these proteins localized near intracellular Shigella. We examined whether interactions among these proteins restrict innate host cell responses other than LC3-associated phagocytosis. In infected cells, OspC3 blocks production and secretion of the mature pro-inflammatory cytokine IL-18; however, we found that interaction of OspC3 with IcsB, either directly or indirectly via Toca-1, was not required for OspC3-mediated restriction of IL-18 production. These results indicate that interactions of the host protein Toca-1 with a subset of type 3 effector proteins contribute to the established function of some, but not all involved, effector proteins.
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Affiliation(s)
- Kelly A Miller
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Anna Cristina Garza-Mayers
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA.,Present address: Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Yiuka Leung
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA.,Present address: Department of Anesthesiology, The Hardin Memorial Hospital Foundation, Inc., Elizabethtown, Kentucky, USA
| | - Marcia B Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
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10
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Abstract
The coevolution of intracellular bacteria with their eukaryotic hosts has presented these pathogens with numerous challenges for their evolutionary progress and survival. Chief among these is the ability to exit from host cells, an event that is fundamentally linked to pathogen dissemination and transmission. Recent years have witnessed a major expansion of research in this area, and this chapter summarizes our current understanding of the spectrum of exit strategies that are exploited by intracellular pathogens. Clear themes regarding the mechanisms of microbial exit have emerged and are most easily conceptualized as (i) lysis of the host cell, (ii) nonlytic exit of free bacteria, and (iii) release of microorganisms into membrane-encased compartments. The adaptation of particular exit strategies is closely linked with additional themes in microbial pathogenesis, including host cell death, manipulation of host signaling pathways, and coincident activation of proinflammatory responses. This chapter will explore the molecular determinants used by intracellular pathogens to promote host cell escape and the infectious advantages each exit pathway may confer, and it will provide an evolutionary framework for the adaptation of these mechanisms.
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11
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Schille S, Crauwels P, Bohn R, Bagola K, Walther P, van Zandbergen G. LC3-associated phagocytosis in microbial pathogenesis. Int J Med Microbiol 2017; 308:228-236. [PMID: 29169848 DOI: 10.1016/j.ijmm.2017.10.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 12/18/2022] Open
Abstract
Phagocytosis is essential for uptake and elimination of pathogenic microorganisms. Autophagy is a highly conserved mechanism for incorporation of cellular constituents to replenish nutrients by degradation. Recently, parts of the autophagy machinery - above all microtubule-associated protein 1 light chain 3 (LC3) - were found to be specifically recruited to phagosomal membranes resulting in phagosome-lysosome fusion and efficient degradation of internalized cargo in a process termed LC3-associated phagocytosis (LAP). Many pathogenic bacterial, fungal and parasitic microorganisms reside within LAP-targeted single-membrane phagosomes or vacuoles after infection of host cells. In this minireview we describe the state of knowledge on the interaction of pathogens with LAP or LAP-like pathways and report on various pathogens that have evolved strategies to circumvent degradation in LAP compartments.
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Affiliation(s)
- Stefan Schille
- Department of Immunology, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany
| | - Peter Crauwels
- Department of Immunology, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany
| | - Rebecca Bohn
- Department of Immunology, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany
| | - Katrin Bagola
- Department of Immunology, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany
| | - Paul Walther
- Central Facility for EM, Ulm University, Ulm, Germany
| | - Ger van Zandbergen
- Department of Immunology, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany; Institute for Immunology, University Medicine Mainz, Langenbeckstraße 1, 55131 Mainz, Germany.
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12
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Lamason RL, Welch MD. Actin-based motility and cell-to-cell spread of bacterial pathogens. Curr Opin Microbiol 2016; 35:48-57. [PMID: 27997855 DOI: 10.1016/j.mib.2016.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 12/17/2022]
Abstract
Subversion of the host actin cytoskeleton is a critical virulence mechanism used by a variety of intracellular bacterial pathogens during their infectious life cycles. These pathogens manipulate host actin to promote actin-based motility and coordinate motility with cell-to-cell spread. Growing evidence suggests that the tactics employed by pathogens are surprisingly diverse. Here, we review recent advances suggesting that bacterial surface proteins exhibit divergent biochemical mechanisms of actin polymerization and recruit distinct host protein networks to drive motility, and that bacteria deploy secreted effector proteins that alter host cell mechanotransduction pathways to enable spread. Further investigation into the divergent strategies used by bacterial pathogens to mobilize actin will reveal new insights into pathogenesis and cytoskeleton regulation.
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Affiliation(s)
- Rebecca L Lamason
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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13
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Agaisse H. Molecular and Cellular Mechanisms of Shigella flexneri Dissemination. Front Cell Infect Microbiol 2016; 6:29. [PMID: 27014639 PMCID: PMC4786538 DOI: 10.3389/fcimb.2016.00029] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/26/2016] [Indexed: 11/13/2022] Open
Abstract
The intracellular pathogen Shigella flexneri is the causative agent of bacillary dysentery in humans. The disease is characterized by bacterial invasion of intestinal cells, dissemination within the colonic epithelium through direct spread from cell to cell, and massive inflammation of the intestinal mucosa. Here, we review the mechanisms supporting S. flexneri dissemination. The dissemination process primarily relies on actin assembly at the bacterial pole, which propels the pathogen throughout the cytosol of primary infected cells. Polar actin assembly is supported by polar expression of the bacterial autotransporter family member IcsA, which recruits the N-WASP/ARP2/3 actin assembly machinery. As motile bacteria encounter cell-cell contacts, they form plasma membrane protrusions that project into adjacent cells. In addition to the ARP2/3-dependent actin assembly machinery, protrusion formation relies on formins and myosins. The resolution of protrusions into vacuoles occurs through the collapse of the protrusion neck, leading to the formation of an intermediate membrane-bound compartment termed vacuole-like protrusions (VLPs). VLP formation requires tyrosine kinase and phosphoinositide signaling in protrusions, which relies on the integrity of the bacterial type 3 secretion system (T3SS). The T3SS is also required for escaping double membrane vacuoles through the activity of the T3SS translocases IpaB and IpaC, and the effector proteins VirA and IcsB. Numerous factors supporting envelope biogenesis contribute to IcsA exposure and maintenance at the bacterial pole, including LPS synthesis, membrane proteases, and periplasmic chaperones. Although less characterized, the assembly and function of the T3SS in the context of bacterial dissemination also relies on factors supporting envelope biogenesis. Finally, the dissemination process requires the adaptation of the pathogen to various cellular compartments through transcriptional and post-transcriptional mechanisms.
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Affiliation(s)
- Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine Charlottesville, VA, USA
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14
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Krokowski S, Mostowy S. Interactions between Shigella flexneri and the Autophagy Machinery. Front Cell Infect Microbiol 2016; 6:17. [PMID: 26904515 PMCID: PMC4748040 DOI: 10.3389/fcimb.2016.00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/25/2016] [Indexed: 11/13/2022] Open
Abstract
Autophagy, an intracellular degradation process, is increasingly recognized as having important roles in host defense. Interactions between Shigella flexneri and the autophagy machinery were first discovered in 2005. Since then, work has shown that multiple autophagy pathways are triggered by S. flexneri, and autophagic responses can have different roles during Shigella infection. Here, we review the interactions between S. flexneri and the autophagy machinery, highlighting that studies using Shigella can reveal the breadth of autophagic responses available to the host.
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Affiliation(s)
- Sina Krokowski
- Department of Medicine, MRC Centre of Molecular Bacteriology and Infection, Imperial College London London, UK
| | - Serge Mostowy
- Department of Medicine, MRC Centre of Molecular Bacteriology and Infection, Imperial College London London, UK
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15
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Van Nhieu GT, Romero S. Common Themes in Cytoskeletal Remodeling by Intracellular Bacterial Effectors. Handb Exp Pharmacol 2016; 235:207-235. [PMID: 27807696 DOI: 10.1007/164_2016_42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Bacterial pathogens interact with various types of tissues to promote infection. Because it controls the formation of membrane extensions, adhesive processes, or the junction integrity, the actin cytoskeleton is a key target of pathogens during infection. We will highlight common and specific functions of the actin cytoskeleton during bacterial infections, by first reviewing the mechanisms of intracellular motility of invasive Shigella, Listeria, and Rickettsia. Through the models of EPEC/EHEC, Shigella, Salmonella, and Chlamydia spp., we will illustrate various strategies of diversion of actin cytoskeletal processes used by these bacteria to colonize or breach epithelial/endothelial barriers.
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Affiliation(s)
- Guy Tran Van Nhieu
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, 75005, Paris, France. .,Institut National de la Santé et de la Recherche Médicale U1050, 75005, Paris, France. .,Centre National de la Recherche Scientifique UMR7241, 75005, Paris, France. .,MEMOLIFE Laboratory of Excellence and Paris Science Lettre, 75005, Paris, France.
| | - Stéphane Romero
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, 75005, Paris, France.,Institut National de la Santé et de la Recherche Médicale U1050, 75005, Paris, France.,Centre National de la Recherche Scientifique UMR7241, 75005, Paris, France.,MEMOLIFE Laboratory of Excellence and Paris Science Lettre, 75005, Paris, France
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16
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Ashida H, Mimuro H, Sasakawa C. Shigella manipulates host immune responses by delivering effector proteins with specific roles. Front Immunol 2015; 6:219. [PMID: 25999954 PMCID: PMC4423471 DOI: 10.3389/fimmu.2015.00219] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/22/2015] [Indexed: 11/30/2022] Open
Abstract
The intestinal epithelium deploys multiple defense systems against microbial infection to sense bacterial components and danger alarms, as well as to induce intracellular signal transduction cascades that trigger both the innate and the adaptive immune systems, which are pivotal for bacterial elimination. However, many enteric bacterial pathogens, including Shigella, deliver a subset of virulence proteins (effectors) via the type III secretion system (T3SS) that enable bacterial evasion from host immune systems; consequently, these pathogens are able to efficiently colonize the intestinal epithelium. In this review, we present and select recently discovered examples of interactions between Shigella and host immune responses, with particular emphasis on strategies that bacteria use to manipulate inflammatory outputs of host-cell responses such as cell death, membrane trafficking, and innate and adaptive immune responses.
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Affiliation(s)
- Hiroshi Ashida
- Division of Bacterial Infection Biology, Institute of Medical Science, University of Tokyo , Tokyo , Japan
| | - Hitomi Mimuro
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, The Institute of Medical Science, University of Tokyo , Tokyo , Japan
| | - Chihiro Sasakawa
- Division of Bacterial Infection Biology, Institute of Medical Science, University of Tokyo , Tokyo , Japan ; Nippon Institute for Biological Science , Tokyo , Japan ; Medical Mycology Research Center, Chiba University , Chiba , Japan
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17
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Valencia-Gallardo CM, Carayol N, Tran Van Nhieu G. Cytoskeletal mechanics during Shigella invasion and dissemination in epithelial cells. Cell Microbiol 2015; 17:174-82. [PMID: 25469430 DOI: 10.1111/cmi.12400] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023]
Abstract
The actin cytoskeleton is key to the barrier function of epithelial cells, by permitting the establishment and maintenance of cell-cell junctions and cell adhesion to the basal matrix. Actin exists under monomeric and polymerized filamentous form and its polymerization following activation of nucleation promoting factors generates pushing forces, required to propel intracellular microorganisms in the host cell cytosol or for the formation of cell extensions that engulf bacteria. Actin filaments can associate with adhesion receptors at the plasma membrane via cytoskeletal linkers. Membrane anchored to actin filaments are then subjected to the retrograde flow that may pull membrane-bound bacteria inside the cell. To induce its internalization by normally non-phagocytic cells, bacteria need to establish adhesive contacts and trick the cell into apply pulling forces, and/or to generate protrusive forces that deform the membrane surrounding its contact site. In this review, we will focus on recent findings on actin cytoskeleton reorganization within epithelial cells during invasion and cell-to-cell spreading by the enteroinvasive pathogen Shigella, the causative agent of bacillary dysentery.
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Affiliation(s)
- Cesar M Valencia-Gallardo
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France; Institut National de la Santé et de la Recherche Médicale (Inserm) U1050, Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7241, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France; Université Paris Diderot - Paris 7, Paris, France
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18
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Affiliation(s)
- Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
- * E-mail:
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19
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Kuehl CJ, Dragoi AM, Agaisse H. The Shigella flexneri type 3 secretion system is required for tyrosine kinase-dependent protrusion resolution, and vacuole escape during bacterial dissemination. PLoS One 2014; 9:e112738. [PMID: 25405985 PMCID: PMC4236203 DOI: 10.1371/journal.pone.0112738] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/14/2014] [Indexed: 01/29/2023] Open
Abstract
Shigella flexneri is a human pathogen that triggers its own entry into intestinal cells and escapes primary vacuoles to gain access to the cytosolic compartment. As cytosolic and motile bacteria encounter the cell cortex, they spread from cell to cell through formation of membrane protrusions that resolve into secondary vacuoles in adjacent cells. Here, we examined the roles of the Type 3 Secretion System (T3SS) in S. flexneri dissemination in HT-29 intestinal cells infected with the serotype 2a strain 2457T. We generated a 2457T strain defective in the expression of MxiG, a central component of the T3SS needle apparatus. As expected, the ΔmxiG strain was severely affected in its ability to invade HT-29 cells, and expression of mxiG under the control of an arabinose inducible expression system (ΔmxiG/pmxiG) restored full infectivity. In this experimental system, removal of the inducer after the invasion steps (ΔmxiG/pmxiG (Ara withdrawal)) led to normal actin-based motility in the cytosol of HT-29 cells. However, the time spent in protrusions until vacuole formation was significantly increased. Moreover, the number of formed protrusions that failed to resolve into vacuoles was also increased. Accordingly, the ΔmxiG/pmxiG (Ara withdrawal) strain failed to trigger tyrosine phosphorylation in membrane protrusions, a signaling event that is required for the resolution of protrusions into vacuoles. Finally, the ΔmxiG/pmxiG (Ara withdrawal) strain failed to escape from the formed secondary vacuoles, as previously reported in non-intestinal cells. Thus, the T3SS system displays multiple roles in S. flexneri dissemination in intestinal cells, including the tyrosine kinase signaling-dependent resolution of membrane protrusions into secondary vacuoles, and the escape from the formed secondary vacuoles.
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Affiliation(s)
- Carole J. Kuehl
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
| | - Ana-Maria Dragoi
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
| | - Hervé Agaisse
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
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20
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Baxt LA, Goldberg MB. Host and bacterial proteins that repress recruitment of LC3 to Shigella early during infection. PLoS One 2014; 9:e94653. [PMID: 24722587 PMCID: PMC3983221 DOI: 10.1371/journal.pone.0094653] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/17/2014] [Indexed: 11/19/2022] Open
Abstract
Shigella spp. are intracytosolic gram-negative pathogens that cause disease by invasion and spread through the colonic mucosa, utilizing host cytoskeletal components to form propulsive actin tails. We have previously identified the host factor Toca-1 as being recruited to intracellular S. flexneri and being required for efficient bacterial actin tail formation. We show that at early times during infection (40 min.), the type three-secreted effector protein IcsB recruits Toca-1 to intracellular bacteria and that recruitment of Toca-1 is associated with repression of recruitment of LC3, as well as with repression of recruitment of the autophagy marker NDP52, around these intracellular bacteria. LC3 is best characterized as a marker of autophagosomes, but also marks phagosomal membranes in the process LC3-associated phagocytosis. IcsB has previously been demonstrated to be required for S. flexneri evasion of autophagy at late times during infection (4-6 hr) by inhibiting binding of the autophagy protein Atg5 to the Shigella surface protein IcsA (VirG). Our results suggest that IcsB and Toca-1 modulation of LC3 recruitment restricts LC3-associated phagocytosis and/or LC3 recruitment to vacuolar membrane remnants. Together with published results, our findings suggest that IcsB inhibits innate immune responses in two distinct ways, first, by inhibiting LC3-associated phagocytosis and/or LC3 recruitment to vacuolar membrane remnants early during infection, and second, by inhibiting autophagy late during infection.
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Affiliation(s)
- Leigh A. Baxt
- Department of Medicine, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marcia B. Goldberg
- Department of Medicine, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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21
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Abstract
Shigella flexneri is an enteropathogenic bacterium responsible for approximately 100 million cases of severe dysentery each year. S. flexneri colonization of the human colonic epithelium is supported by direct spread from cell to cell, which relies on actin-based motility. We have recently uncovered that, in intestinal epithelial cells, S. flexneri actin-based motility is regulated by the Bruton's tyrosine kinase (Btk). Consequently, treatment with Ibrutinib, a specific Btk inhibitor currently used in the treatment of B-cell malignancies, effectively impaired S. flexneri spread from cell to cell. Thus, therapeutic intervention capitalizing on drugs interfering with host factors supporting the infection process may represent an effective alternative to treatments with antimicrobial compounds.
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22
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Carayol N, Tran Van Nhieu G. The inside story of Shigella invasion of intestinal epithelial cells. Cold Spring Harb Perspect Med 2013; 3:a016717. [PMID: 24086068 DOI: 10.1101/cshperspect.a016717] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
As opposed to other invasive pathogens that reside into host cells in a parasitic mode, Shigella, the causative agent of bacillary dysentery, invades the colonic mucosa but does not penetrate further to survive into deeper tissues. Instead, Shigella invades, replicates, and disseminates within the colonic mucosa. Bacterial invasion and spreading in intestinal epithelium lead to the elicitation of inflammatory responses responsible for the tissue destruction and shedding in the environment for further infection of other hosts. In this article, we highlight specific features of the Shigella arsenal of virulence determinants injected by a type III secretion apparatus (T3SA) that point to the targeting of intestinal epithelial cells as a discrete route of invasion during the initial event of the infectious process.
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Affiliation(s)
- Nathalie Carayol
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
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23
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Abstract
Intracellular pathogens have developed elaborate mechanisms to exploit the different cellular systems of their unwilling hosts to facilitate their entry, replication, and survival. In particular, a diverse range of bacteria and viruses have evolved unique strategies to harness the power of Arp2/3-mediated actin polymerization to enhance their cell-to-cell spread. In this review, we discuss how studying these pathogens has revolutionized our molecular understanding of Arp2/3-dependent actin assembly and revealed key signaling pathways regulating actin assembly in cells. Future analyses of microbe-host interactions are likely to continue uncovering new mechanisms regulating actin assembly and dynamics, as well as unexpected cellular functions for actin. Further, studies with known and newly emerging pathogens will also undoubtedly continue to enhance our understanding of the role of the actin cytoskeleton during pathogenesis and potentially highlight future therapeutic approaches.
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Affiliation(s)
- Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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24
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Abstract
Several bacterial pathogens, including Listeria monocytogenes, Shigella flexneri and Rickettsia spp., have evolved mechanisms to actively spread within human tissues. Spreading is initiated by the pathogen-induced recruitment of host filamentous (F)-actin. F-actin forms a tail behind the microbe, propelling it through the cytoplasm. The motile pathogen then encounters the host plasma membrane, forming a bacterium-containing protrusion that is engulfed by an adjacent cell. Over the past two decades, much progress has been made in elucidating mechanisms of F-actin tail formation. Listeria and Shigella produce tails of branched actin filaments by subverting the host Arp2/3 complex. By contrast, Rickettsia forms tails with linear actin filaments through a bacterial mimic of eukaryotic formins. Compared with F-actin tail formation, mechanisms controlling bacterial protrusions are less well understood. However, recent findings have highlighted the importance of pathogen manipulation of host cell–cell junctions in spread. Listeria produces a soluble protein that enhances bacterial protrusions by perturbing tight junctions. Shigella protrusions are engulfed through a clathrin-mediated pathway at ‘tricellular junctions’—specialized membrane regions at the intersection of three epithelial cells. This review summarizes key past findings in pathogen spread, and focuses on recent developments in actin-based motility and the formation and internalization of bacterial protrusions.
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Affiliation(s)
- Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
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25
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Bruton's tyrosine kinase regulates Shigella flexneri dissemination in HT-29 intestinal cells. Infect Immun 2012; 81:598-607. [PMID: 23230296 DOI: 10.1128/iai.00853-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Shigella flexneri is a Gram-negative intracellular pathogen that infects the intestinal epithelium and utilizes actin-based motility to spread from cell to cell. S. flexneri actin-based motility has been characterized in various cell lines, but studies in intestinal cells are limited. Here we characterized S. flexneri actin-based motility in HT-29 intestinal cells. In agreement with studies conducted in various cell lines, we showed that S. flexneri relies on neural Wiskott-Aldrich Syndrome protein (N-WASP) in HT-29 cells. We tested the potential role of various tyrosine kinases involved in N-WASP activation and uncovered a previously unappreciated role for Bruton's tyrosine kinase (Btk) in actin tail formation in intestinal cells. We showed that Btk depletion led to a decrease in N-WASP phosphorylation which affected N-WASP recruitment to the bacterial surface, decreased the number of bacteria displaying actin-based motility, and ultimately affected the efficiency of spread from cell to cell. Finally, we showed that the levels of N-WASP phosphorylation and Btk expression were increased in response to infection, which suggests that S. flexneri infection not only triggers the production of proinflammatory factors as previously described but also manipulates cellular processes required for dissemination in intestinal cells.
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26
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Mostowy S. Autophagy and bacterial clearance: a not so clear picture. Cell Microbiol 2012; 15:395-402. [PMID: 23121192 PMCID: PMC3592990 DOI: 10.1111/cmi.12063] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 10/13/2012] [Accepted: 10/15/2012] [Indexed: 12/28/2022]
Abstract
Autophagy, an intracellular degradation process highly conserved from yeast to humans, is viewed as an important defence mechanism to clear intracellular bacteria. However, recent work has shown that autophagy may have different roles during different bacterial infections that restrict bacterial replication (antibacterial autophagy), act in cell autonomous signalling (non-bacterial autophagy) or support bacterial replication (pro-bacterial autophagy). This review will focus on newfound interactions of autophagy and pathogenic bacteria, highlighting that, in addition to delivering bacteria to the lysosome, autophagy responding to bacterial invasion may have a much broader role in mediating disease outcome.
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Affiliation(s)
- Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK.
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27
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Fields AT, Navarrete CS, Zare AZ, Huang Z, Mostafavi M, Lewis JC, Rezaeihaghighi Y, Brezler BJ, Ray S, Rizzacasa AL, Barnett MJ, Long SR, Chen EJ, Chen JC. The conserved polarity factor podJ1 impacts multiple cell envelope-associated functions in Sinorhizobium meliloti. Mol Microbiol 2012; 84:892-920. [PMID: 22553970 DOI: 10.1111/j.1365-2958.2012.08064.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although diminutive in size, bacteria possess highly diverse and spatially confined cellular structures. Two related alphaproteobacteria, Sinorhizobium meliloti and Caulobacter crescentus, serve as models for investigating the genetic basis of morphological variations. S. meliloti, a symbiont of leguminous plants, synthesizes multiple flagella and no prosthecae, whereas C. crescentus, a freshwater bacterium, has a single polar flagellum and stalk. The podJ gene, originally identified in C. crescentus for its role in polar organelle development, is split into two adjacent open reading frames, podJ1 and podJ2, in S. meliloti. Deletion of podJ1 interferes with flagellar motility, exopolysaccharide production, cell envelope integrity, cell division and normal morphology, but not symbiosis. As in C. crescentus, the S. meliloti PodJ1 protein appears to act as a polarity beacon and localizes to the newer cell pole. Microarray analysis indicates that podJ1 affects the expression of at least 129 genes, the majority of which correspond to observed mutant phenotypes. Together, phenotypic characterization, microarray analysis and suppressor identification suggest that PodJ1 controls a core set of conserved elements, including flagellar and pili genes, the signalling proteins PleC and DivK, and the transcriptional activator TacA, while alternative downstream targets have evolved to suit the distinct lifestyles of individual species.
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Affiliation(s)
- Alexander T Fields
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
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28
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Campellone KG, Siripala AD, Leong JM, Welch MD. Membrane-deforming proteins play distinct roles in actin pedestal biogenesis by enterohemorrhagic Escherichia coli. J Biol Chem 2012; 287:20613-24. [PMID: 22544751 DOI: 10.1074/jbc.m112.363473] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Many bacterial pathogens reorganize the host actin cytoskeleton during the course of infection, including enterohemorrhagic Escherichia coli (EHEC), which utilizes the effector protein EspF(U) to assemble actin filaments within plasma membrane protrusions called pedestals. EspF(U) activates N-WASP, a host actin nucleation-promoting factor that is normally auto-inhibited and found in a complex with the actin-binding protein WIP. Under native conditions, this N-WASP/WIP complex is activated by the small GTPase Cdc42 in concert with several different SH3 (Src-homology-3) domain-containing proteins. In the current study, we tested whether SH3 domains from the F-BAR (FCH-Bin-Amphiphysin-Rvs) subfamily of membrane-deforming proteins are involved in actin pedestal formation. We found that three F-BAR proteins: CIP4, FBP17, and TOCA1 (transducer of Cdc42-dependent actin assembly), play different roles during actin pedestal biogenesis. Whereas CIP4 and FBP17 inhibited actin pedestal assembly, TOCA1 stimulated this process. TOCA1 was recruited to pedestals by its SH3 domain, which bound directly to proline-rich sequences within EspF(U). Moreover, EspF(U) and TOCA1 activated the N-WASP/WIP complex in an additive fashion in vitro, suggesting that TOCA1 can augment actin assembly within pedestals. These results reveal that EspF(U) acts as a scaffold to recruit multiple actin assembly factors whose functions are normally regulated by Cdc42.
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Affiliation(s)
- Kenneth G Campellone
- Department of Molecular & Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA.
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Haglund CM, Welch MD. Pathogens and polymers: microbe-host interactions illuminate the cytoskeleton. ACTA ACUST UNITED AC 2011; 195:7-17. [PMID: 21969466 PMCID: PMC3187711 DOI: 10.1083/jcb.201103148] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Intracellular pathogens subvert the host cell cytoskeleton to promote their own survival, replication, and dissemination. Study of these microbes has led to many discoveries about host cell biology, including the identification of cytoskeletal proteins, regulatory pathways, and mechanisms of cytoskeletal function. Actin is a common target of bacterial pathogens, but recent work also highlights the use of microtubules, cytoskeletal motors, intermediate filaments, and septins. The study of pathogen interactions with the cytoskeleton has illuminated key cellular processes such as phagocytosis, macropinocytosis, membrane trafficking, motility, autophagy, and signal transduction.
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Affiliation(s)
- Cat M Haglund
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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30
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Fricke R, Gohl C, Bogdan S. The F-BAR protein family Actin' on the membrane. Commun Integr Biol 2011; 3:89-94. [PMID: 20585497 DOI: 10.4161/cib.3.2.10521] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 11/03/2009] [Indexed: 11/19/2022] Open
Abstract
A tight spatio-temporal coordination of the machineries controlling actin dynamics and membrane remodelling is crucial for a huge variety of cellular processes that shape cells into a multicellular organism. Dynamic membrane remodelling is achieved by a functional relationship between proteins that control plasma membrane curvature, membrane fission and nucleation of new actin filaments. The BAR/F-BAR-domain-containing proteins are prime candidates to couple plasma membrane curvature and actin dynamics in different morphogenetic processes. Here, we discuss recent findings on the membrane-shaping proteins of the F-BAR domain subfamily and how they regulate morphogenetic processes in vivo.
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Affiliation(s)
- Robert Fricke
- Institut für Neurobiologie; Wilhelms-University; Münster; Münster, Germany
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31
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Hu J, Mukhopadhyay A, Truesdell P, Chander H, Mukhopadhyay UK, Mak AS, Craig AWB. Cdc42-interacting protein 4 is a Src substrate that regulates invadopodia and invasiveness of breast tumors by promoting MT1-MMP endocytosis. J Cell Sci 2011; 124:1739-51. [PMID: 21525036 DOI: 10.1242/jcs.078014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Invadopodia are actin-rich membrane protrusions that promote extracellular matrix degradation and invasiveness of tumor cells. Src protein-tyrosine kinase is a potent inducer of invadopodia and tumor metastases. Cdc42-interacting protein 4 (CIP4) adaptor protein interacts with actin regulatory proteins and regulates endocytosis. Here, we show that CIP4 is a Src substrate that localizes to invadopodia in MDA-MB-231 breast tumor cells expressing activated Src (MDA-SrcYF). To probe the function of CIP4 in invadopodia, we established stable CIP4 knockdown in MDA-SrcYF cell lines by RNA interference. Compared with control cells, CIP4 knockdown cells degrade more extracellular matrix (ECM), have increased numbers of mature invadopodia and are more invasive through matrigel. Similar results are observed with knockdown of CIP4 in EGF-treated MDA-MB-231 cells. This inhibitory role of CIP4 is explained by our finding that CIP4 limits surface expression of transmembrane type I matrix metalloprotease (MT1-MMP), by promoting MT1-MMP internalization. Ectopic expression of CIP4 reduces ECM digestion by MDA-SrcYF cells, and this activity is enhanced by mutation of the major Src phosphorylation site in CIP4 (Y471). Overall, our results identify CIP4 as a suppressor of Src-induced invadopodia and invasion in breast tumor cells by promoting endocytosis of MT1-MMP.
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Affiliation(s)
- Jinghui Hu
- Department of Biochemistry, Queen's University, Kingston, ON K7L 3N6 Canada
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32
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Day B, Henty JL, Porter KJ, Staiger CJ. The pathogen-actin connection: a platform for defense signaling in plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:483-506. [PMID: 21495845 DOI: 10.1146/annurev-phyto-072910-095426] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The cytoskeleton, a dynamic network of cytoplasmic polymers, plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. As a platform for innate immune responses in mammalian cells, the actin cytoskeleton is a central component in the organization and activation of host defenses, including signaling and cellular repair. In plants, our understanding of the genetic and biochemical responses in both pathogen and host that are required for virulence and resistance has grown enormously. Additional advances in live-cell imaging of cytoskeletal dynamics have markedly altered our view of actin turnover in plants. In this review, we outline current knowledge of host resistance following pathogen perception, both in terms of the genetic interactions that mediate defense signaling, as well as the biochemical and cellular processes that are required for defense signaling.
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Affiliation(s)
- Brad Day
- Department of Plant Pathology, Michigan State University, East Lansing, Michigan 48824-1311, USA.
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Hu J, Mukhopadhyay A, Craig AWB. Transducer of Cdc42-dependent actin assembly promotes epidermal growth factor-induced cell motility and invasiveness. J Biol Chem 2010; 286:2261-72. [PMID: 21062739 DOI: 10.1074/jbc.m110.157974] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Toca-1 (transducer of Cdc42-dependent actin assembly) interacts with the Cdc42·N-WASP and Abi1·Rac·WAVE F-actin branching pathways that function in lamellipodia formation and cell motility. However, the potential role of Toca-1 in these processes has not been reported. Here, we show that epidermal growth factor (EGF) induces Toca-1 localization to lamellipodia, where it co-localizes with F-actin and Arp2/3 complex in A431 epidermoid carcinoma cells. EGF also induces tyrosine phosphorylation of Toca-1 and interactions with N-WASP and Abi1. Stable knockdown of Toca-1 expression by RNA interference has no effect on cell growth, EGF receptor expression, or internalization. However, Toca-1 knockdown cells display defects in EGF-induced filopodia and lamellipodial protrusions compared with control cells. Further analyses reveal a role for Toca-1 in localization of Arp2/3 and Abi1 to lamellipodia. Toca-1 knockdown cells also display a significant defect in EGF-induced motility and invasiveness. Taken together, these results implicate Toca-1 in coordinating actin assembly within filopodia and lamellipodia to promote EGF-induced cell migration and invasion.
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Affiliation(s)
- Jinghui Hu
- Department of Biochemistry and the Cancer Biology and Genetics Division, Queen's University Cancer Research Institute, Queen's University Kingston, Ontario K7L 3N6, Canada
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Sasakawa C. A new paradigm of bacteria-gut interplay brought through the study of Shigella. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:229-243. [PMID: 20228623 PMCID: PMC3417848 DOI: 10.2183/pjab.86.229] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 01/08/2010] [Indexed: 05/28/2023]
Abstract
Bacteria-gut epithelial interplay and the mucosal immune response are the most critical issues in determining the fate of bacterial infection and the severity of diseases. Shigella species (abbreviated here as Shigella), the causative agent of bacillary dysentery (shigellosis), are highly adapted human pathogens that are capable of invading and colonizing the intestinal epithelium, which results in severe inflammatory colitis. Shigella secrete a large and diverse number (more then 50) of effectors via the type III secretion system (TTSS) during infection, some of which are delivered into the surrounding bacterial space and some others into the host cell cytoplasm and nucleus. The delivered effectors mimic and usurp the host cellular functions, and modulate host cell signaling and immune response, thus playing pivotal roles in promoting bacterial infection and circumventing host defense systems. This article overviews the pathogenic characteristics of Shigella, and highlights current topics related to the bacterial infectious stratagem executed by the TTSS-secreted effectors. Though bacterial stratagems and the molecular mechanisms of infection vary greatly among pathogens, the current studies of Shigella provide a paradigm shift in bacterial pathogenesis.
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Affiliation(s)
- Chihiro Sasakawa
- Department of Microbiology and Immunology, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
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Huett A, Xavier RJ. Autophagy at the gut interface: mucosal responses to stress and the consequences for inflammatory bowel diseases. Inflamm Bowel Dis 2010; 16:152-74. [PMID: 19575363 PMCID: PMC3954538 DOI: 10.1002/ibd.20991] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Autophagy is a conserved homeostatic process by which cells degrade and recycle cytoplasmic contents and organelles. Recently, autophagy has come to prominence as a factor in many disease states, including inflammatory bowel diseases. In this review we explore the recent discoveries in autophagy and how these relate to the special conditions experienced by the gut mucosa. We will pay particular attention to autophagy as an innate immune process and its role in the development and education of the adaptive immune system.
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Affiliation(s)
- Alan Huett
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA,Gastrointestinal Unit, Center for Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
| | - Ramnik J. Xavier
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA,Gastrointestinal Unit, Center for Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA,The Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
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Dodding MP, Way M. Nck- and N-WASP-Dependent Actin-Based Motility Is Conserved in Divergent Vertebrate Poxviruses. Cell Host Microbe 2009; 6:536-50. [DOI: 10.1016/j.chom.2009.10.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 09/29/2009] [Accepted: 10/13/2009] [Indexed: 01/21/2023]
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F-BAR proteins of the syndapin family shape the plasma membrane and are crucial for neuromorphogenesis. J Neurosci 2009; 29:13315-27. [PMID: 19846719 DOI: 10.1523/jneurosci.3973-09.2009] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Coordinated functions of the actin cytoskeleton and microtubules, which require careful control in time and space, are indispensable for the drastic alterations of neuronal morphology during neuromorphogenesis and neuronal network formation. Actin filament formation driven by the Arp2/3 complex and its activator neural Wiskott-Aldrich syndrome protein (N-WASP) is important for proper axon development. The underlying molecular mechanisms for targeting to and specific activation of N-WASP at the neuronal plasma membrane, however, have thus far remained elusive. We show that syndapin I is critical for proper neuromorphogenesis and hereby uses N-WASP as a cytoskeletal effector. Upon N-WASP binding, syndapins release N-WASP autoinhibition. Syndapins hereby cooperate with Cdc42 and phosphatidyl-inositol-(4,5)-bisphosphate. Syndapins furthermore specifically bind to phosphatidylserine-containing membranes via their extended F-BAR domain. Dissecting the syndapin functions actin nucleation and direct membrane binding in vivo, we demonstrate that both functions are physiologically relevant and required. Constitutive plasma membrane-targeting experiments in vivo indicate that specifically actin nucleation at the cell cortex is triggered by syndapins. Consistent with syndapins steering N-WASP as downstream effector for cortical actin nucleation, syndapin-induced neuronal arborization is N-WASP and Cdc42 dependent. The functions of syndapin-N-WASP complexes in neuromorphogenesis were revealed by loss-of-function studies. Knockdown of syndapin I leads to impaired axon development and especially phenocopies the aberrant axon branching observed upon N-WASP and Arp2/3 complex deficiency. In contrast, proper length control involves another N-WASP-binding protein, Abp1. Our data thus reveal that syndapin I is crucial for neuromorphogenesis and that different N-WASP activators ensure fine control of N-WASP activity and have distinct functions during neuronal network formation.
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Requirement for formin-induced actin polymerization during spread of Shigella flexneri. Infect Immun 2009; 78:193-203. [PMID: 19841078 DOI: 10.1128/iai.00252-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Actin polymerization in the cytosol and at the plasma membrane is locally regulated by actin nucleators. Several microbial pathogens exploit cellular actin polymerization to spread through tissue. The movement of the enteric pathogen Shigella flexneri, both within the cell body and from cell to cell, depends on actin polymerization. During intercellular spread, actin polymerization at the bacterial surface generates protrusions of the plasma membrane, which are engulfed by adjacent cells. In the cell body, polymerization of actin by Shigella spp. is dependent on N-WASP activation of the Arp2/Arp3 complex. Here we demonstrate that, in contrast, efficient protrusion formation and intercellular spread depend on actin polymerization that involves activation of the Diaphanous formin Dia. While the Shigella virulence protein IpgB2 can bind and activate Dia1 (N. M. Alto et al., Cell 124:133-145, 2006), its absence does not result in a detectable defect in Dia-dependent protrusion formation or spread. The dependence on the activation of Dia during S. flexneri infection contrasts with the inhibition of this pathway observed during vaccinia virus infection.
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Abstract
WASP, the product of the gene mutated in Wiskott-Aldrich syndrome, is expressed only in hematopoietic cells and is the archetype of a family of proteins that include N-WASP and Scar/WAVE. WASP plays a critical role in T cell activation and actin reorganization. WASP has multiple protein-interacting domains. Through its N-terminal EVH1 domain WASP binds to its partner WASP interacting protein (WIP) and through its C-terminal end it interacts with and activates the Arp2/3 complex. In lymphocytes, most of WASP is sequestered with WIP and binding to WIP is essential for the stability of WASP. The central proline-rich region of WASP serves as docking site to several adaptor proteins. Through these multiple interactions WASP integrates many cellular signals to actin cytoskeleton remodeling. In this review, we have summarized recent developments in the biology of WASP and the role of WIP in regulating WASP function. We also discuss WASP-independent functions of WIP.
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Affiliation(s)
- Narayanaswamy Ramesh
- Division of Immunology, Department of Pediatrics, Childrens Hospital, Harvard Medical School, Karp 10 One Blackfan Circle, Boston, MA, 02115, USA
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Hu J, Troglio F, Mukhopadhyay A, Everingham S, Kwok E, Scita G, Craig AWB. F-BAR-containing adaptor CIP4 localizes to early endosomes and regulates Epidermal Growth Factor Receptor trafficking and downregulation. Cell Signal 2009; 21:1686-97. [PMID: 19632321 DOI: 10.1016/j.cellsig.2009.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 07/08/2009] [Accepted: 07/16/2009] [Indexed: 12/12/2022]
Abstract
Cdc42-Interacting Protein-4 (CIP4) family adaptors have been implicated in promoting Epidermal Growth Factor Receptor (EGFR) internalization, however, their unique or overlapping functions remain unclear. Here, we show that although CIP4 was not required for early events in clathrin-mediated endocytosis of EGFR, CIP4 localizes to vesicles containing EGFR and Rab5. Furthermore, expression of constitutively active Rab5 led to accumulation of CIP4 and the related adaptor Toca-1 in giant endosomes. Using a mutagenesis approach, we show that localization of CIP4 to endosomes is mediated in part via the curved phosphoinositide-binding face of the CIP4 F-BAR domain. Downregulation of CIP4 in A431 epidermoid carcinoma cells by RNA interference led to elevated EGFR levels, compared to control cells. Although surface expression of EGFR was not affected by CIP4 silencing, EGF-induced transit of EGFR from EEA1-positive endosomes to lysosomes was reduced compared to control cells. This correlated with more robust activation of ERK kinase and entry to S phase in CIP4-depleted A431 cells, compared to control cells. The combined silencing of CIP4 and Toca-1 was more effective in driving cells into S phase, suggesting a partial redundancy in their functions. Overall, our results implicate CIP4 and Toca-1 in regulating late events in EGFR trafficking from endosomes that serves to limit sustained ERK activation within the endosomal compartment.
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Affiliation(s)
- Jinghui Hu
- Queen's University Cancer Research Institute, Division of Cancer Biology & Genetics and Department of Biochemistry, Queen's University, Kingston, Ontario, Canada
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Huett A, Ng A, Cao Z, Kuballa P, Komatsu M, Daly MJ, Podolsky DK, Xavier RJ. A novel hybrid yeast-human network analysis reveals an essential role for FNBP1L in antibacterial autophagy. THE JOURNAL OF IMMUNOLOGY 2009; 182:4917-30. [PMID: 19342671 DOI: 10.4049/jimmunol.0803050] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autophagy is a conserved cellular process required for the removal of defective organelles, protein aggregates, and intracellular pathogens. We used a network analysis strategy to identify novel human autophagy components based upon the yeast interactome centered on the core yeast autophagy proteins. This revealed the potential involvement of 14 novel mammalian genes in autophagy, several of which have known or predicted roles in membrane organization or dynamics. We selected one of these membrane interactors, FNBP1L (formin binding protein 1-like), an F-BAR-containing protein (also termed Toca-1), for further study based upon a predicted interaction with ATG3. We confirmed the FNBP1L/ATG3 interaction biochemically and mapped the FNBP1L domains responsible. Using a functional RNA interference approach, we determined that FNBP1L is essential for autophagy of the intracellular pathogen Salmonella enterica serovar Typhimurium and show that the autophagy process serves to restrict the growth of intracellular bacteria. However, FNBP1L appears dispensable for other forms of autophagy induced by serum starvation or rapamycin. We present a model where FNBP1L is essential for autophagy of intracellular pathogens and identify FNBP1L as a differentially used molecule in specific autophagic contexts. By using network biology to derive functional biological information, we demonstrate the utility of integrated genomics to novel molecule discovery in autophagy.
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Affiliation(s)
- Alan Huett
- Center for Computational and Integrative Biology, MassachusettsGeneral Hospital, Harvard Medical School, Boston, MA 02114, USA
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Adamovich DA, Nakamura F, Worth A, Burns S, Thrasher AJ, Hartwig JH, Snapper SB. Activating mutations of N-WASP alter Shigella pathogenesis. Biochem Biophys Res Commun 2009; 384:284-9. [PMID: 19379711 DOI: 10.1016/j.bbrc.2009.04.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 04/13/2009] [Indexed: 10/25/2022]
Abstract
The pathogenesis of Shigella requires binding to the host protein N-WASP. To examine the roles of structural conformation and phospho-regulation of N-WASP during Shigella pathogenesis, mutant N-WASP constructs predicted to result in a constitutively open conformation (L229P and L232P) or either a phospho-mimicking (Y253E) or phospho-disruptive (Y253F) structure were constructed. Pyrene actin assays demonstrated that the N-WASP L229P and L232P constructs are constitutively active. Despite the increase in actin polymerization seen in vitro, cell lines expressing N-WASP L229P and L232P supported shorter actin tails when infected with Shigella. Shigella actin tails were unchanged in cells expressing N-WASP phospho-regulation mutant proteins. Shigella invasion, intracellular, and intercellular motility were not altered in cells expressing N-WASP L229P or L232P. However, plaque numbers were increased in cells expressing N-WASP L229P and L232P. These data demonstrate that N-WASP structural conformation is an important regulator of Shigella pathogenesis in distinct segments of its lifecycle.
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Affiliation(s)
- David A Adamovich
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA 02114, USA
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Shigella Infection of Intestinal Epithelium and Circumvention of the Host Innate Defense System. Curr Top Microbiol Immunol 2009; 337:231-55. [DOI: 10.1007/978-3-642-01846-6_8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Aspenström P. Roles of F-BAR/PCH proteins in the regulation of membrane dynamics and actin reorganization. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 272:1-31. [PMID: 19121815 DOI: 10.1016/s1937-6448(08)01601-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Pombe Cdc15 Homology (PCH) proteins have emerged in many species as important coordinators of signaling pathways that regulate actomyosin assembly and membrane dynamics. The hallmark of the PCH proteins is the presence of a Fes/CIP4 homology-Bin/Amphiphysin/Rvsp (F-BAR) domain; therefore they are commonly referred to as F-BAR proteins. The prototype F-BAR protein, Cdc15p of Schizosaccharomyces pombe, has a role in the formation of the contractile actomyosin ring during cytokinesis. Vertebrate F-BAR proteins have an established role in binding phospholipids and they participate in membrane deformations, for instance, during the internalization of transmembrane receptors. This way the F-BAR proteins will function as linkers between the actin polymerization apparatus and the machinery regulating membrane dynamics. Interestingly, some members of the F-BAR proteins are implicated in inflammatory or neurodegenerative disorders and the observations can be expected to have clinical implications for the treatment of the diseases.
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Affiliation(s)
- Pontus Aspenström
- Ludwig Institute for Cancer Research, Uppsala University, SE-751 24 Uppsala, Sweden
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