1
|
Bienvenu A, Burette M, Cantet F, Gourdelier M, Swain J, Cazevieille C, Clemente T, Sadi A, Dupont C, Le Fe M, Bonetto N, Bordignon B, Muriaux D, Gilk S, Bonazzi M, Martinez E. The multifunction Coxiella effector Vice stimulates macropinocytosis and interferes with the ESCRT machinery. Proc Natl Acad Sci U S A 2024; 121:e2315481121. [PMID: 38870060 PMCID: PMC11194487 DOI: 10.1073/pnas.2315481121] [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: 09/06/2023] [Accepted: 04/25/2024] [Indexed: 06/15/2024] Open
Abstract
Intracellular bacterial pathogens divert multiple cellular pathways to establish their niche and persist inside their host. Coxiella burnetii, the causative agent of Q fever, secretes bacterial effector proteins via its Type 4 secretion system to generate a Coxiella-containing vacuole (CCV). Manipulation of lipid and protein trafficking by these effectors is essential for bacterial replication and virulence. Here, we have characterized the lipid composition of CCVs and found that the effector Vice interacts with phosphoinositides and membranes enriched in phosphatidylserine and lysobisphosphatidic acid. Remarkably, eukaryotic cells ectopically expressing Vice present compartments that resemble early CCVs in both morphology and composition. We found that the biogenesis of these compartments relies on the double function of Vice. The effector protein initially localizes at the plasma membrane of eukaryotic cells where it triggers the internalization of large vacuoles by macropinocytosis. Then, Vice stabilizes these compartments by perturbing the ESCRT machinery. Collectively, our results reveal that Vice is an essential C. burnetii effector protein capable of hijacking two major cellular pathways to shape the bacterial replicative niche.
Collapse
Affiliation(s)
- Arthur Bienvenu
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Melanie Burette
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Franck Cantet
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Manon Gourdelier
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Jitendriya Swain
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Chantal Cazevieille
- Institut des Neurosciences de Montpellier (INM), Université de Montpellier, INSERM, Montpellier34090, France
| | - Tatiana Clemente
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE68198-5900
| | - Arif Sadi
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE68198-5900
| | - Claire Dupont
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Manon Le Fe
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Nicolas Bonetto
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Benoit Bordignon
- Montpellier Rio Imaging (MRI), BioCampus Montpellier, CNRS, INSERM, Université de Montpellier, Montpellier34090, France
| | - Delphine Muriaux
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Stacey Gilk
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE68198-5900
| | - Matteo Bonazzi
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| | - Eric Martinez
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier34090, France
| |
Collapse
|
2
|
Chatterjee R, Setty SRG, Chakravortty D. SNAREs: a double-edged sword for intravacuolar bacterial pathogens within host cells. Trends Microbiol 2024; 32:477-493. [PMID: 38040624 DOI: 10.1016/j.tim.2023.11.002] [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: 08/05/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 12/03/2023]
Abstract
In the tug-of-war between host and pathogen, both evolve to combat each other's defence arsenals. Intracellular phagosomal bacteria have developed strategies to modify the vacuolar niche to suit their requirements best. Conversely, the host tries to target the pathogen-containing vacuoles towards the degradative pathways. The host cells use a robust system through intracellular trafficking to maintain homeostasis inside the cellular milieu. In parallel, intracellular bacterial pathogens have coevolved with the host to harbour strategies to manipulate cellular pathways, organelles, and cargoes, facilitating the conversion of the phagosome into a modified pathogen-containing vacuole (PCV). Key molecular regulators of intracellular traffic, such as changes in the organelle (phospholipid) composition, recruitment of small GTPases and associated effectors, soluble N-ethylmaleimide-sensitive factor-activating protein receptors (SNAREs), etc., are hijacked to evade lysosomal degradation. Legionella, Salmonella, Coxiella, Chlamydia, Mycobacterium, and Brucella are examples of pathogens which diverge from the endocytic pathway by using effector-mediated mechanisms to overcome the challenges and establish their intracellular niches. These pathogens extensively utilise and modulate the end processes of secretory pathways, particularly SNAREs, in repurposing the PCV into specialised compartments resembling the host organelles within the secretory network; at the same time, they avoid being degraded by the host's cellular mechanisms. Here, we discuss the recent research advances on the host-pathogen interaction/crosstalk that involves host SNAREs, conserved cellular processes, and the ongoing host-pathogen defence mechanisms in the molecular arms race against each other. The current knowledge of SNAREs, and intravacuolar bacterial pathogen interactions, enables us to understand host cellular innate immune pathways, maintenance of homeostasis, and potential therapeutic strategies to combat ever-growing antimicrobial resistance.
Collapse
Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India.
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India; Adjunct Faculty, Indian Institute of Science Research and Education, Thiruvananthapuram, Kerala, India.
| |
Collapse
|
3
|
Salloum G, Bresnick AR, Backer JM. Macropinocytosis: mechanisms and regulation. Biochem J 2023; 480:335-362. [PMID: 36920093 DOI: 10.1042/bcj20210584] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/16/2023]
Abstract
Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.
Collapse
Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Jonathan M Backer
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| |
Collapse
|
4
|
VAMP3 and VAMP8 regulate the development and functionality of parasitophorous vacuoles housing Leishmania amazonensis. Infect Immun 2022; 90:e0018321. [PMID: 35130453 DOI: 10.1128/iai.00183-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To colonize mammalian phagocytic cells, the parasite Leishmania remodels phagosomes into parasitophorous vacuoles that can be either tight-fitting individual or communal. The molecular and cellular bases underlying the biogenesis and functionality of these two types of vacuoles are poorly understood. In this study, we investigated the contribution of host cell Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor proteins to the expansion and functionality of communal vacuoles as well as on the replication of the parasite. The differential recruitment patterns of Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor to communal vacuoles harboring L. amazonensis and to individual vacuoles housing L. major led us to further investigate the roles of VAMP3 and VAMP8 in the interaction of Leishmania with its host cell. We show that whereas VAMP8 contributes to optimal expansion of communal vacuoles, VAMP3 negatively regulates L. amazonensis replication, vacuole size, as well as antigen cross-presentation. In contrast, neither proteins has an impact on the fate of L. major. Collectively, our data support a role for both VAMP3 and VAMP8 in the development and functionality of L. amazonensis-harboring communal parasitophorous vacuoles.
Collapse
|
5
|
Macrophage Proteome Analysis at Different Stages of Mycobacterium avium Subspecies paratuberculosis Infection Reveals a Mechanism of Pathogen Dissemination. Proteomes 2021; 9:proteomes9020020. [PMID: 33946162 PMCID: PMC8162536 DOI: 10.3390/proteomes9020020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Johne’s disease is a chronic and usually fatal enteric infection of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP) and is responsible for hundreds of millions of dollars in losses for the agricultural industry. Natural infection typically begins with bacterial uptake and translocation through the epithelium of the small intestine, followed by ingestion by tissue macrophages and dissemination via the lymphatic or blood system throughout the body. To gain insights into the host responses and adaptation of MAP within phagocytic cells, we utilized the previously developed cell culture passage model, and mass spectrometric-based quantitative proteomic approach. Using the cell culture system, which mimics an in vivo interaction of MAP with intestinal epithelium and tissue macrophages, bacteria were passed through the bovine epithelial cells and, subsequently, used for macrophage infection (termed indirect infection), while uninfected cells and macrophage infection initiated with the culture grown bacteria (termed direct infection) served as controls. Approximately 3900 proteins were identified across all studied groups. The comparison within the subset of proteins that showed synthesis for more than two-fold in the direct infection over the uninfected control revealed an enrichment for the pro-inflammatory pathways such as the NF-κB and cytokine/chemokine signaling, positive regulation of defense response, cell activation involved in the immune response and adaptive immune system. While these responses were absent in the indirect infection, cellular pathways such as cell cycle, healing, regulation of cell adhesion, ensemble of core extracellular matrix proteins, cell surface integrins and proteins mediating the integrin signaling were remarkably high within the indirect infection. In addition to global analysis of the macrophage proteome, we further validated the proteomics data and confirmed that MAP passage through epithelial cells modulates the expression and signaling of integrins in phagocytes. In this study, we demonstrate that predominant expression of integrins in the indirectly infected macrophages allows phagocytic cells to initiate stronger binding and efficient translocation through the endothelial cells, suggesting the important role of integrins in the spread of MAP infection.
Collapse
|
6
|
Nguyen JA, Yates RM. Better Together: Current Insights Into Phagosome-Lysosome Fusion. Front Immunol 2021; 12:636078. [PMID: 33717183 PMCID: PMC7946854 DOI: 10.3389/fimmu.2021.636078] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022] Open
Abstract
Following phagocytosis, the nascent phagosome undergoes maturation to become a phagolysosome with an acidic, hydrolytic, and often oxidative lumen that can efficiently kill and digest engulfed microbes, cells, and debris. The fusion of phagosomes with lysosomes is a principal driver of phagosomal maturation and is targeted by several adapted intracellular pathogens. Impairment of this process has significant consequences for microbial infection, tissue inflammation, the onset of adaptive immunity, and disease. Given the importance of phagosome-lysosome fusion to phagocyte function and the many virulence factors that target it, it is unsurprising that multiple molecular pathways have evolved to mediate this essential process. While the full range of these pathways has yet to be fully characterized, several pathways involving proteins such as members of the Rab GTPases, tethering factors and SNAREs have been identified. Here, we summarize the current state of knowledge to clarify the ambiguities in the field and construct a more comprehensive phagolysosome formation model. Lastly, we discuss how other cellular pathways help support phagolysosome biogenesis and, consequently, phagocyte function.
Collapse
Affiliation(s)
- Jenny A Nguyen
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Robin M Yates
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Snyder Institute of Chronic Disease, University of Calgary, Calgary, AB, Canada
| |
Collapse
|
7
|
Stévenin V, Chang YY, Le Toquin Y, Duchateau M, Gianetto QG, Luk CH, Salles A, Sohst V, Matondo M, Reiling N, Enninga J. Dynamic Growth and Shrinkage of the Salmonella-Containing Vacuole Determines the Intracellular Pathogen Niche. Cell Rep 2020; 29:3958-3973.e7. [PMID: 31851926 PMCID: PMC6931108 DOI: 10.1016/j.celrep.2019.11.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/23/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
Salmonella is a human and animal pathogen that causes gastro-enteric diseases. The key to Salmonella infection is its entry into intestinal epithelial cells, where the bacterium resides within a Salmonella-containing vacuole (SCV). Salmonella entry also induces the formation of empty macropinosomes, distinct from the SCV, in the vicinity of the entering bacteria. A few minutes after its formation, the SCV increases in size through fusions with the surrounding macropinosomes. Salmonella also induces membrane tubules that emanate from the SCV and lead to SCV shrinkage. Here, we show that these antipodal events are utilized by Salmonella to either establish a vacuolar niche or to be released into the cytosol by SCV rupture. We identify the molecular machinery underlying dynamic SCV growth and shrinkage. In particular, the SNARE proteins SNAP25 and STX4 participate in SCV inflation by fusion with macropinosomes. Thus, host compartment size control emerges as a pathogen strategy for intracellular niche regulation. The early SCV simultaneously grows and shrinks through fusion and tubule formation SCV shrinkage promotes vacuolar rupture and cytosolic release IAMs are enriched in the host SNAREs SNAP25 and STX4, enabling IAM-SCV fusion Promoting SNX1-mediated tubule formation, SopB fosters SCV ruptures
Collapse
Affiliation(s)
- Virginie Stévenin
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Yuen-Yan Chang
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Yoann Le Toquin
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Magalie Duchateau
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France
| | - Quentin Giai Gianetto
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France; Institut Pasteur, Bioinformatics and Biostatistics HUB, C3BI, USR CNRS 3756, Paris, France
| | - Chak Hon Luk
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Audrey Salles
- Institut Pasteur, UtechS Photonic BioImaging PBI (Imagopole), Centre de Recherche et de Ressources Technologiques C2RT, Paris, France
| | - Victoria Sohst
- Research Center Borstel, Leibniz Lung Center, RG Microbial Interface Biology, Parkallee 22, 23845 Borstel, Germany
| | - Mariette Matondo
- Institut Pasteur, Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR 2000 CNRS, Paris, France
| | - Norbert Reiling
- Research Center Borstel, Leibniz Lung Center, RG Microbial Interface Biology, Parkallee 22, 23845 Borstel, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Jost Enninga
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France.
| |
Collapse
|
8
|
Kehl A, Göser V, Reuter T, Liss V, Franke M, John C, Richter CP, Deiwick J, Hensel M. A trafficome-wide RNAi screen reveals deployment of early and late secretory host proteins and the entire late endo-/lysosomal vesicle fusion machinery by intracellular Salmonella. PLoS Pathog 2020; 16:e1008220. [PMID: 32658937 PMCID: PMC7377517 DOI: 10.1371/journal.ppat.1008220] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 07/23/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022] Open
Abstract
The intracellular lifestyle of Salmonella enterica is characterized by the formation of a replication-permissive membrane-bound niche, the Salmonella-containing vacuole (SCV). As a further consequence of the massive remodeling of the host cell endosomal system, intracellular Salmonella establish a unique network of various Salmonella-induced tubules (SIT). The bacterial repertoire of effector proteins required for the establishment for one type of these SIT, the Salmonella-induced filaments (SIF), is rather well-defined. However, the corresponding host cell proteins are still poorly understood. To identify host factors required for the formation of SIF, we performed a sub-genomic RNAi screen. The analyses comprised high-resolution live cell imaging to score effects on SIF induction, dynamics and morphology. The hits of our functional RNAi screen comprise: i) The late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, consisting of STX7, STX8, VTI1B, and VAMP7 or VAMP8, which is, in conjunction with RAB7 and the homotypic fusion and protein sorting (HOPS) tethering complex, a complete vesicle fusion machinery. ii) Novel interactions with the early secretory GTPases RAB1A and RAB1B, providing a potential link to coat protein complex I (COPI) vesicles and reinforcing recently identified ties to the endoplasmic reticulum. iii) New connections to the late secretory pathway and/or the recycling endosome via the GTPases RAB3A, RAB8A, and RAB8B and the SNAREs VAMP2, VAMP3, and VAMP4. iv) An unprecedented involvement of clathrin-coated structures. The resulting set of hits allowed us to characterize completely new host factor interactions, and to strengthen observations from several previous studies. The facultative intracellular pathogen Salmonella enterica serovar Typhimurium induces the reorganization of the endosomal system of mammalian host cells. This activity is dependent on translocated effector proteins of the pathogen. The host cell factors required for endosomal remodeling are only partially known. To identify such factors for the formation and dynamics of endosomal compartments in Salmonella-infected cells, we performed a live cell imaging-based RNAi screen to investigate the role of 496 mammalian proteins involved in cellular logistics. We identified that endosomal remodeling by intracellular Salmonella is dependent on host factors in the following functional classes: i) the late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, ii) the early secretory pathway, represented by regulator GTPases RAB1A and RAB1B, iii) the late secretory pathway and/or recycling endosomes represented by GTPases RAB3A, RAB8A, RAB8B, and the SNAREs VAMP2, VAMP3, and VAMP4, and iv) clathrin-coated structures. The identification of these new host factors provides further evidence for the complex manipulation of host cell transport functions by intracellular Salmonella and should enable detailed follow-up studies on the mechanisms involved.
Collapse
Affiliation(s)
- Alexander Kehl
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- Division of Biophysics, University of Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
| | - Vera Göser
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Tatjana Reuter
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Viktoria Liss
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Maximilian Franke
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Christopher John
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | | | - Jörg Deiwick
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- CellNanOs–Center for Cellular Nanoanalytics, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
| |
Collapse
|
9
|
Lau N, Haeberle AL, O’Keeffe BJ, Latomanski EA, Celli J, Newton HJ, Knodler LA. SopF, a phosphoinositide binding effector, promotes the stability of the nascent Salmonella-containing vacuole. PLoS Pathog 2019; 15:e1007959. [PMID: 31339948 PMCID: PMC6682159 DOI: 10.1371/journal.ppat.1007959] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 08/05/2019] [Accepted: 07/02/2019] [Indexed: 12/19/2022] Open
Abstract
The enteric bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), utilizes two type III secretion systems (T3SSs) to invade host cells, survive and replicate intracellularly. T3SS1 and its dedicated effector proteins are required for bacterial entry into non-phagocytic cells and establishment and trafficking of the nascent Salmonella-containing vacuole (SCV). Here we identify the first T3SS1 effector required to maintain the integrity of the nascent SCV as SopF. SopF associates with host cell membranes, either when translocated by bacteria or ectopically expressed. Recombinant SopF binds to multiple phosphoinositides in protein-lipid overlays, suggesting that it targets eukaryotic cell membranes via phospholipid interactions. In yeast, the subcellular localization of SopF is dependent on the activity of Mss4, a phosphatidylinositol 4-phosphate 5-kinase that generates PI(4,5)P2 from PI(4)P, indicating that membrane recruitment of SopF requires specific phospholipids. Ectopically expressed SopF partially colocalizes with specific phosphoinositide pools present on the plasma membrane in mammalian cells and with cytoskeletal-associated markers at the leading edge of cells. Translocated SopF concentrates on plasma membrane ruffles and around intracellular bacteria, presumably on the SCV. SopF is not required for bacterial invasion of non-phagocytic cells but is required for maintenance of the internalization vacuole membrane as infection with a S. Typhimurium ΔsopF mutant led to increased lysis of the SCV compared to wild type bacteria. Our structure-function analysis shows that the carboxy-terminal seven amino acids of SopF are essential for its membrane association in host cells and to promote SCV membrane stability. We also describe that SopF and another T3SS1 effector, SopB, act antagonistically to modulate nascent SCV membrane dynamics. In summary, our study highlights that a delicate balance of type III effector activities regulates the stability of the Salmonella internalization vacuole.
Collapse
Affiliation(s)
- Nicole Lau
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Amanda L. Haeberle
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Brittany J. O’Keeffe
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Eleanor A. Latomanski
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Jean Celli
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Hayley J. Newton
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (LAK); (HJN)
| | - Leigh A. Knodler
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
- * E-mail: (LAK); (HJN)
| |
Collapse
|
10
|
Dingjan I, Linders PTA, Verboogen DRJ, Revelo NH, Ter Beest M, van den Bogaart G. Endosomal and Phagosomal SNAREs. Physiol Rev 2018; 98:1465-1492. [PMID: 29790818 DOI: 10.1152/physrev.00037.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.
Collapse
Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Danielle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Natalia H Revelo
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| |
Collapse
|
11
|
Qiu S, Côté M. From hitchhiker to hijacker: pathogen exploitation of endosomal phosphoinositides 1. Biochem Cell Biol 2018; 97:1-9. [PMID: 29746785 DOI: 10.1139/bcb-2017-0317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Signalling through phosphoinositide lipids is essential for regulating many cellular processes, including endosomal trafficking. A number of intracellular pathogens have found ways to subvert host trafficking pathways via exploitation of endosomal phosphoinositides. This review will discuss how pathogens such as bacteria, viruses, and eukaryotic parasites depend on endosomal phosphoinositides for infection as well as the mechanisms through which some are able to actively manipulate these signalling lipids to facilitate invasion, survival, replication, and immune evasion.
Collapse
Affiliation(s)
- Shirley Qiu
- a Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,b Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,c Center for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Marceline Côté
- a Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,b Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,c Center for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| |
Collapse
|
12
|
Jeschke A, Haas A. Sequential actions of phosphatidylinositol phosphates regulate phagosome-lysosome fusion. Mol Biol Cell 2017; 29:452-465. [PMID: 29237821 PMCID: PMC6014173 DOI: 10.1091/mbc.e17-07-0464] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/14/2017] [Accepted: 12/08/2017] [Indexed: 02/05/2023] Open
Abstract
Phagosome-with-lysosome fusion comprises subreactions with differential lipid requirements: PI(4)P is required during and after phagosome-to-lysosome tethering, and PI(3)P is required after tethering. Moreover, PI(4)P serves to anchor to (phago)lysosome membranes Arl8 and HOPS, whereas PI(3)P contributes to membrane binding of HOPS only. Phagosomes mature into phagolysosomes by sequential fusion with early endosomes, late endosomes, and lysosomes. Phagosome-with-lysosome fusion (PLF) results in the delivery of lysosomal hydrolases into phagosomes and in digestion of the cargo. The machinery that drives PLF has been little investigated. Using a cell-free system, we recently identified the phosphoinositide lipids (PIPs) phosphatidylinositol 3-phosphate (PI(3)P) and phosphatidylinositol 4-phosphate (PI(4)P) as regulators of PLF. We now report the identification and the PIP requirements of four distinct subreactions of PLF. Our data show that (i) PI(3)P and PI(4)P are dispensable for the disassembly and activation of (phago)lysosomal soluble N-ethylmaleimide-sensitive factor attachment protein receptors, that (ii) PI(3)P is required only after the tethering step, and that (iii) PI(4)P is required during and after tethering. Moreover, our data indicate that PI(4)P is needed to anchor Arl8 (Arf-like GTPase 8) and its effector homotypic fusion/vacuole protein sorting complex (HOPS) to (phago)lysosome membranes, whereas PI(3)P is required for membrane association of HOPS only. Our study provides a first link between PIPs and established regulators of membrane fusion in late endocytic trafficking.
Collapse
Affiliation(s)
- Andreas Jeschke
- Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
| | - Albert Haas
- Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
| |
Collapse
|
13
|
Vashi N, Andrabi SBA, Ghanwat S, Suar M, Kumar D. Ca 2+-dependent Focal Exocytosis of Golgi-derived Vesicles Helps Phagocytic Uptake in Macrophages. J Biol Chem 2017; 292:5144-5165. [PMID: 28174296 DOI: 10.1074/jbc.m116.743047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/12/2017] [Indexed: 11/06/2022] Open
Abstract
The role of Golgi apparatus during phagocytic uptake by macrophages has been ruled out in the past. Notably, all such reports were limited to Fcγ receptor-mediated phagocytosis. Here, we unravel a highly devolved mechanism for recruitment of Golgi-derived secretory vesicles during phagosome biogenesis, which was important for uptake of most cargos, except the IgG-coated ones. We report recruitment of mannosidase-II-positive Golgi-derived vesicles during uptake of diverse targets, including latex beads, Escherichia coli, Salmonella typhimurium, and Mycobacterium tuberculosis in human and mouse macrophages. The recruitment of mannosidase-II vesicles was an early event mediated by focal exocytosis and coincided with the recruitment of transferrin receptor, VAMP3, and dynamin-2. Brefeldin A treatment inhibited mannosidase-II recruitment and phagocytic uptake of serum-coated or -uncoated latex beads and E. coli However, consistent with previous studies, brefeldin A treatment did not affect uptake of IgG-coated latex beads. Mechanistically, recruitment of mannosidase-II vesicles during phagocytic uptake required Ca2+ from both extra- and intracellular sources apart from PI3K, microtubules, and dynamin-2. Extracellular Ca2+ via voltage-gated Ca2+ channels established a Ca2+-dependent local phosphatidylinositol 1,4,5-trisphosphate gradient, which guides the focal movement of Golgi-derived vesicles to the site of uptake. We confirmed Golgi-derived vesicles recruited during phagocytosis were secretory vesicles as their recruitment was sensitive to depletion of VAMP2 or NCS1, whereas recruitment of the recycling endosome marker VAMP3 was unaffected. Depletion of both VAMP2 and NCS1 individually resulted in the reduced uptake by macrophages. Together, the study provides a previously unprecedented role of Golgi-derived secretory vesicles in phagocytic uptake, the key innate defense function.
Collapse
Affiliation(s)
- Nimi Vashi
- From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and
| | - Syed Bilal Ahmad Andrabi
- From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and
| | - Swapnil Ghanwat
- From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and
| | - Mrutyunjay Suar
- the School of Biotechnology, KIIT University, Bhubaneswar-751024, India
| | - Dhiraj Kumar
- From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and
| |
Collapse
|
14
|
Teo WX, Kerr MC, Teasdale RD. MTMR4 Is Required for the Stability of the Salmonella-Containing Vacuole. Front Cell Infect Microbiol 2016; 6:91. [PMID: 27625994 PMCID: PMC5003867 DOI: 10.3389/fcimb.2016.00091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 08/15/2016] [Indexed: 12/22/2022] Open
Abstract
The intracellular pathogen Salmonella enterica servovar Typhimurium (S.typhimurium) modulates the host cell's phosphoinositide (PI) metabolism to establish its intracellular replicative niche, the Salmonella-containing vacuole (SCV). Upon invasion, phosphoinositide 3-phosphate (PI(3)P) and other early endosomal markers are rapidly recruited to and remain associated with the SCV throughout its early maturation. While the phosphoinositide 3-phosphatase myotubularin 4 (MTMR4) has an established role in regulating autophagy and cellular PI(3)P-content, two processes associated with the intracellular survival of S. typhimurium, a direct role for MTMR4 in Salmonella biology has not been examined. Here we demonstrate that GFP-tagged MTMR4 is recruited to the SCV and infection of cells depleted of endogenous MTMR4 results in a decrease in viable intracellular Salmonella. This reflects a significant increase in the proportion of SCVs with compromised integrity, which targets the compartment for autophagy and consequent bacterial cell death. These findings highlight the importance of PI(3)P regulation to the integrity of the SCV and reveal a novel role for the myotubularins in bacterial pathogenesis.
Collapse
Affiliation(s)
- Wei X Teo
- Institute for Molecular Bioscience, University of Queensland Brisbane, QLD, Australia
| | - Markus C Kerr
- Institute for Molecular Bioscience, University of Queensland Brisbane, QLD, Australia
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, University of Queensland Brisbane, QLD, Australia
| |
Collapse
|
15
|
Deciphering the roles of phosphoinositide lipids in phagolysosome biogenesis. Commun Integr Biol 2016; 9:e1174798. [PMID: 27489580 PMCID: PMC4951175 DOI: 10.1080/19420889.2016.1174798] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 01/01/2023] Open
Abstract
Professional phagocytes engulf microbial invaders into plasma membrane-derived phagosomes. These mature into microbicidal phagolysosomes, leading to killing of the ingested microbe. Phagosome maturation involves sequential fusion of the phagosome with early endosomes, late endosomes, and the main degradative compartments in cells, lysosomes. Some bacterial pathogens manipulate the phosphoinositide (PIP) composition of phagosome membranes and are not delivered to phagolysosomes, pointing at a role of PIPs in phagosome maturation. This hypothesis is supported by comprehensive microscopic studies. Recently, cell-free reconstitution of fusion between phagosomes and endo(lyso)somes identified phosphatidylinositol 4-phosphate [PI(4)P] and phosphatidylinositol 3-phosphate [PI(3)P] as key regulators of phagolysosome biogenesis. Here, we describe the emerging roles of PIPs in phagosome maturation and we present tools to study PIP involvement in phagosome trafficking using intact cells or purified compartments.
Collapse
|
16
|
Piscatelli HL, Li M, Zhou D. Dual 4- and 5-phosphatase activities regulate SopB-dependent phosphoinositide dynamics to promote bacterial entry. Cell Microbiol 2015; 18:705-19. [PMID: 26537021 DOI: 10.1111/cmi.12542] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 10/21/2015] [Accepted: 10/24/2015] [Indexed: 12/16/2022]
Abstract
Salmonella are able to invade non-phagocytic cells such as intestinal epithelial cells by modulating the host actin cytoskeleton to produce membrane ruffles. Two type III effector proteins SopB and SopE play key roles to this modulation. SopE is a known guanine nucleotide exchange factor (GEF) capable of activating Rac1 and CDC42. SopB is a phosphatidylinositol 4-phosphatase and 5-phosphatase promoting membrane ruffles and invasion of Salmonella through undefined mechanisms. Previous studies have demonstrated that the 4-phosphatase activity of SopB is required for PtdIns-3-phosphate (PtdIns(3)P) accumulation and SopB-mediated invasion. We show here that both the 4-phosphatase as well as the 5-phosphatase activities of SopB are essential in ruffle formation and subsequent invasion. We found that the 5-phosphatase activity of SopB is likely responsible for generating PtdIns-3,4-bisphosphate (PtdIns(3,4)P(2)) and subsequent recruitment of sorting nexin 9 (SNX9), an actin modulating protein. Intriguingly, the 4-phosphatase activity is responsible for the dephosphorylation of PtdIns(3,4)P(2) into PtdIns(3)P. Alone, neither activity is sufficient for ruffling but when acting in conjunction with one another, the 4-phosphatase and 5-phosphatase activities led to SNX9-mediated ruffling and Salmonella invasion. This work reveals the unique ability of bacterial effector protein SopB to utilize both its 4- and 5-phosphatase activities to regulate phosphoinositide dynamics to promote bacterial entry.
Collapse
Affiliation(s)
- Heather L Piscatelli
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Menghan Li
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Daoguo Zhou
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
17
|
Phosphatidylinositol 4-phosphate and phosphatidylinositol 3-phosphate regulate phagolysosome biogenesis. Proc Natl Acad Sci U S A 2015; 112:4636-41. [PMID: 25825728 DOI: 10.1073/pnas.1423456112] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Professional phagocytic cells ingest microbial intruders by engulfing them into phagosomes, which subsequently mature into microbicidal phagolysosomes. Phagosome maturation requires sequential fusion of the phagosome with early endosomes, late endosomes, and lysosomes. Although various phosphoinositides (PIPs) have been detected on phagosomes, it remained unclear which PIPs actually govern phagosome maturation. Here, we analyzed the involvement of PIPs in fusion of phagosomes with various endocytic compartments and identified phosphatidylinositol 4-phosphate [PI(4)P], phosphatidylinositol 3-phosphate [PI(3)P], and the lipid kinases that generate these PIPs, as mediators of phagosome-lysosome fusion. Phagosome-early endosome fusion required PI(3)P, yet did not depend on PI(4)P. Thus, PI(3)P regulates phagosome maturation at early and late stages, whereas PI(4)P is selectively required late in the pathway.
Collapse
|
18
|
Ellem SJ, Taylor RA, Furic L, Larsson O, Frydenberg M, Pook D, Pedersen J, Cawsey B, Trotta A, Need E, Buchanan G, Risbridger GP. A pro-tumourigenic loop at the human prostate tumour interface orchestrated by oestrogen, CXCL12 and mast cell recruitment. J Pathol 2014; 234:86-98. [PMID: 25042571 DOI: 10.1002/path.4386] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 05/18/2014] [Accepted: 05/30/2014] [Indexed: 12/21/2022]
Abstract
Prostate cancer is hormone-dependent and regulated by androgens as well as oestrogens. The tumour microenvironment also provides regulatory control, but the balance and interplay between androgens and oestrogens at the human prostate tumour interface is unknown. This study reveals a central and dominant role for oestrogen in the microenvironment, fuelling a pro-tumourigenic loop of inflammatory cytokines involving recruitment of mast cells by carcinoma-associated fibroblasts (CAFs). Mast cell numbers were increased in human PCa clinical specimens, specifically within the peritumoural stroma. Human mast cells were also shown to express ERα and ERβ, with oestradiol directly stimulating mast cell proliferation and migration as well as altered cytokine/chemokine expression. There was a significant shift in the oestrogen:androgen balance in CAFs versus normal prostatic fibroblasts (NPFs), with a profound increase to ER:AR expression. Androgen signalling is also reduced in CAFs, while ERα and ERβ transcriptional activity is not, allowing oestrogen to dictate hormone action in the tumour microenvironment. Gene microarray analyses identified CXCL12 as a major oestrogen-driven target gene in CAFs, and CAFs recruit mast cells via CXCL12 in a CXCR4-dependent manner. Collectively, these data reveal multicellular oestrogen action in the tumour microenvironment and show dominant oestrogen, rather than androgen, signalling at the prostatic tumour interface.
Collapse
Affiliation(s)
- Stuart J Ellem
- Prostate Cancer Research Group, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Roppenser B, Kwon H, Canadien V, Xu R, Devreotes PN, Grinstein S, Brumell JH. Multiple host kinases contribute to Akt activation during Salmonella infection. PLoS One 2013; 8:e71015. [PMID: 23990921 PMCID: PMC3750030 DOI: 10.1371/journal.pone.0071015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/24/2013] [Indexed: 01/05/2023] Open
Abstract
SopB is a type 3 secreted effector with phosphatase activity that Salmonella employs to manipulate host cellular processes, allowing the bacteria to establish their intracellular niche. One important function of SopB is activation of the pro-survival kinase Akt/protein kinase B in the infected host cell. Here, we examine the mechanism of Akt activation by SopB during Salmonella infection. We show that SopB-mediated Akt activation is only partially sensitive to PI3-kinase inhibitors LY294002 and wortmannin in HeLa cells, suggesting that Class I PI3-kinases play only a minor role in this process. However, depletion of PI(3,4) P2/PI(3-5) P3 by expression of the phosphoinositide 3-phosphatase PTEN inhibits Akt activation during Salmonella invasion. Therefore, production of PI(3,4) P2/PI(3-5) P3 appears to be a necessary event for Akt activation by SopB and suggests that non-canonical kinases mediate production of these phosphoinositides during Salmonella infection. We report that Class II PI3-kinase beta isoform, IPMK and other kinases identified from a kinase screen all contribute to Akt activation during Salmonella infection. In addition, the kinases required for SopB-mediated activation of Akt vary depending on the type of infected host cell. Together, our data suggest that Salmonella has evolved to use a single effector, SopB, to manipulate a remarkably large repertoire of host kinases to activate Akt for the purpose of optimizing bacterial replication in its host.
Collapse
Affiliation(s)
- Bernhard Roppenser
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hyunwoo Kwon
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Veronica Canadien
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Risheng Xu
- Department of Neuroscience, Johns Hopkins Medical School, Baltimore, Maryland, United States of America
| | - Peter N. Devreotes
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sergio Grinstein
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - John H. Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Sickkids IBD Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| |
Collapse
|
20
|
Perrett CA, Zhou D. Salmonella type III effector SopB modulates host cell exocytosis. Emerg Microbes Infect 2013; 2:e32. [PMID: 26038467 PMCID: PMC3675406 DOI: 10.1038/emi.2013.31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 03/16/2013] [Accepted: 03/14/2013] [Indexed: 11/09/2022]
Abstract
Salmonella enterica pathogenesis is dependent on its ability to enter and replicate inside host cells. Replication occurs inside the Salmonella-containing vacuole (SCV), a vacuolar compartment that is modified by bacterial effectors secreted through the two type III secretion systems (T3SS-1 and T3SS-2). Type III effectors interact with the host cell endocytic pathway to aid replication. We investigated whether Salmonella effector proteins may also interact with the host's exocytic pathway. A secreted alkaline phosphatase (SEAP) assay indicated three Salmonella effectors inhibited the secretory pathway, although only Salmonella outer protein B (SopB) was confirmed to block exocytosis using a vesicular stomatitis virus glycoprotein-green fluorescent protein (VSVG-GFP) transport assay. The 4-phosphatase activity of SopB was crucial to its effect on exocytosis. The interaction with the secretory pathway could potentially be important for providing replicating Salmonella with nutrients, contributing membrane material necessary for SCV biogenesis, altering antibacterial peptide/protein secretion or manipulating cell surface proteins important in the host response to infection.
Collapse
Affiliation(s)
- Charlotte A Perrett
- Department of Biological Sciences, Purdue University , West Lafayette, IN 47907, USA
| | - Daoguo Zhou
- Department of Biological Sciences, Purdue University , West Lafayette, IN 47907, USA
| |
Collapse
|
21
|
Jiang RHY, Stahelin RV, Bhattacharjee S, Haldar K. Eukaryotic virulence determinants utilize phosphoinositides at the ER and host cell surface. Trends Microbiol 2013; 21:145-56. [PMID: 23375057 DOI: 10.1016/j.tim.2012.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 12/12/2012] [Accepted: 12/18/2012] [Indexed: 01/03/2023]
Abstract
Similar to bacteria, eukaryotic pathogens may utilize common strategies of pathogenic secretion, because effector proteins from the oomycete Phytophthora infestans and virulence determinants from the human malaria parasite Plasmodium falciparum share a functionally equivalent host-cell-targeting motif (RxLR-dEER in P. infestans and RxLxE/D/Q in P. falciparum). Here we summarize recent studies that reveal that the malarial motif may function differently than previously envisioned. Binding of the lipid phosphatidylinositol 3-phosphate [PI(3)P] is a critical step in accessing the host for both pathogens, but occurs in different locations. Nanomolar affinity for PI(3)P by these short amino acid motifs suggests that a newly identified mechanism of phosphoinositide binding that unexpectedly occurs in secretory locations has been exploited for virulence by diverse eukaryotic pathogens.
Collapse
Affiliation(s)
- Rays H Y Jiang
- Department of Infectious Diseases and Immunology, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | | | | | | |
Collapse
|
22
|
Ramos-Morales F. Impact of Salmonella enterica Type III Secretion System Effectors on the Eukaryotic Host Cell. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/787934] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type III secretion systems are molecular machines used by many Gram-negative bacterial pathogens to inject proteins, known as effectors, directly into eukaryotic host cells. These proteins manipulate host signal transduction pathways and cellular processes to the pathogen’s advantage. Salmonella enterica possesses two virulence-related type III secretion systems that deliver more than forty effectors. This paper reviews our current knowledge about the functions, biochemical activities, host targets, and impact on host cells of these effectors. First, the concerted action of effectors at the cellular level in relevant aspects of the interaction between Salmonella and its hosts is analyzed. Then, particular issues that will drive research in the field in the near future are discussed. Finally, detailed information about each individual effector is provided.
Collapse
Affiliation(s)
- Francisco Ramos-Morales
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, 41012 Sevilla, Spain
| |
Collapse
|
23
|
|
24
|
van der Heijden J, Finlay BB. Type III effector-mediated processes in Salmonella infection. Future Microbiol 2012; 7:685-703. [DOI: 10.2217/fmb.12.49] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Salmonella is one of the most successful bacterial pathogens that infect humans in both developed and developing countries. In order to cause infection, Salmonella uses type III secretion systems to inject bacterial effector proteins into host cells. In the age of antibiotic resistance, researchers have been looking for new strategies to reduce Salmonella infection. To understand infection and to analyze type III secretion as a potential therapeutic target, research has focused on identification of effectors, characterization of effector functions and how they contribute to disease. Many effector-mediated processes have been identified that contribute to infection but thus far no specific treatment has been found. In this perspective we discuss our current understanding of effector-mediated processes and discuss new techniques and approaches that may help us to find a solution to this worldwide problem.
Collapse
Affiliation(s)
- Joris van der Heijden
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - B Brett Finlay
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
25
|
|
26
|
Falasca M, Maffucci T. Regulation and cellular functions of class II phosphoinositide 3-kinases. Biochem J 2012; 443:587-601. [PMID: 22507127 DOI: 10.1042/bj20120008] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Class II isoforms of PI3K (phosphoinositide 3-kinase) are still the least investigated and characterized of all PI3Ks. In the last few years, an increased interest in these enzymes has improved our understanding of their cellular functions. However, several questions still remain unanswered on their mechanisms of activation, their specific downstream effectors and their contribution to physiological processes and pathological conditions. Emerging evidence suggests that distinct PI3Ks activate different signalling pathways, indicating that their functional roles are probably not redundant. In the present review, we discuss the recent advances in our understanding of mammalian class II PI3Ks and the evidence suggesting their involvement in human diseases.
Collapse
Affiliation(s)
- Marco Falasca
- Inositide Signalling Group, Centre for Diabetes, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK.
| | | |
Collapse
|
27
|
Kaiser P, Diard M, Stecher B, Hardt WD. The streptomycin mouse model for Salmonella diarrhea: functional analysis of the microbiota, the pathogen's virulence factors, and the host's mucosal immune response. Immunol Rev 2012; 245:56-83. [PMID: 22168414 DOI: 10.1111/j.1600-065x.2011.01070.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The mammalian intestine is colonized by a dense microbial community, the microbiota. Homeostatic and symbiotic interactions facilitate the peaceful co-existence between the microbiota and the host, and inhibit colonization by most incoming pathogens ('colonization resistance'). However, if pathogenic intruders overcome colonization resistance, a fierce, innate inflammatory defense can be mounted within hours, the adaptive arm of the immune system is initiated, and the pathogen is fought back. The molecular nature of the homeostatic interactions, the pathogen's ability to overcome colonization resistance, and the triggering of native and adaptive mucosal immune responses are still poorly understood. To study these mechanisms, the streptomycin mouse model for Salmonella diarrhea is of great value. Here, we review how S. Typhimurium triggers mucosal immune responses by active (virulence factor elicited) and passive (MyD88-dependent) mechanisms and introduce the S. Typhimurium mutants available for focusing on either response. Interestingly, mucosal defense turns out to be a double-edged sword, limiting pathogen burdens in the gut tissue but enhancing pathogen growth in the gut lumen. This model allows not only studying the molecular pathogenesis of Salmonella diarrhea but also is ideally suited for analyzing innate defenses, microbe handling by mucosal phagocytes, adaptive secretory immunoglobulin A responses, probing microbiota function, and homeostatic microbiota-host interactions. Finally, we discuss the general need for defined assay conditions when using animal models for enteric infections and the central importance of littermate controls.
Collapse
Affiliation(s)
- Patrick Kaiser
- Institute of Microbiology, D-BIOL, ETH Zürich, Zürich, Switzerland
| | | | | | | |
Collapse
|
28
|
Rogers LD, Brown NF, Fang Y, Pelech S, Foster LJ. Phosphoproteomic analysis of Salmonella-infected cells identifies key kinase regulators and SopB-dependent host phosphorylation events. Sci Signal 2012; 4:rs9. [PMID: 21934108 DOI: 10.1126/scisignal.2001668] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Salmonella enterica is a bacterial pathogen that causes gastroenteritis and typhoid fever. Virulence is achieved by two type III secretion systems that translocate effector proteins into host cells, where they mimic or block host protein function. Effectors translocated into host cells by the first type III secretion system facilitate invasion and stimulate intracellular signaling cascades leading to inflammation. Here, we performed global temporal analysis of host signaling events induced during the initial stages of Salmonella infection and identified the dynamics of host protein phosphorylation as well as differences between growth factor-stimulated and bacteria-induced signaling. Informatics analysis predicted that sites with altered phosphorylation in infected cells were targeted by the serine-threonine kinases Akt, protein kinase C, and Pim and that up to half of the host phosphorylation events detected after Salmonella infection required the effector protein SopB. Our data reveal extensive manipulation of host phosphorylation cascades by this Salmonella effector and provide a detailed map of the events leading to intestinal inflammation, which is the crucial host response that enables Salmonella to proliferate in the intestine.
Collapse
Affiliation(s)
- Lindsay D Rogers
- Centre for High-Throughput Biology and Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | | | | | | | | |
Collapse
|
29
|
Payrastre B, Gaits-Iacovoni F, Sansonetti P, Tronchère H. Phosphoinositides and cellular pathogens. Subcell Biochem 2012; 59:363-388. [PMID: 22374097 DOI: 10.1007/978-94-007-3015-1_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Phosphoinositides are considered as highly dynamic players in the spatiotemporal organization of key signaling pathways, actin cytoskeleton rearrangements, establishment of cell polarity and intracellular vesicle trafficking. Their metabolism is accurately controlled and mutations in several phosphoinositide metabolizing enzymes take part in the development of human pathologies. Interestingly, evidence is accumulating that modulation of the phosphoinositide metabolism is critical for pathogenicity and virulence of many human pathogens. Given the importance of phosphoinositides, which link membrane and cytoskeleton dynamics to cell responses, it is not surprising that many invasive pathogens hijack their metabolism as part of their strategies to establish infection. In fact, according to their lifestyle, cellular pathogens use the phosphoinositide metabolism in order to trigger their uptake in nonphagocytic cells and/or modulate the maturation of the pathogen-containing vacuole to establish their replicative niche or escape in the cytosol and promote host cell survival. The last two decades have been marked by the discovery of different tactics used by cellular pathogens to modulate the phosphoinositide metabolism as part of their strategies to survive, proliferate and disseminate in a hostile environment.
Collapse
Affiliation(s)
- Bernard Payrastre
- Inserm, U1048, Université Toulouse 3, I2MC, Hôpital de Toulouse, BP 84225 Avenue Jean Poulhès, 31432, Toulouse Cedex 04, France,
| | | | | | | |
Collapse
|
30
|
Carlin LM, Evans R, Milewicz H, Fernandes L, Matthews DR, Perani M, Levitt J, Keppler MD, Monypenny J, Coolen T, Barber PR, Vojnovic B, Suhling K, Fraternali F, Ameer-Beg S, Parker PJ, Thomas NSB, Ng T. A targeted siRNA screen identifies regulators of Cdc42 activity at the natural killer cell immunological synapse. Sci Signal 2011; 4:ra81. [PMID: 22126964 DOI: 10.1126/scisignal.2001729] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Natural killer (NK) cells kill tumor cells and virally infected cells, and an effective NK cell response requires processes, such as motility, recognition, and directional secretion, that rely on cytoskeletal rearrangement. The Rho guanosine triphosphatase (GTPase) Cdc42 coordinates cytoskeletal reorganization downstream of many receptors. The Rho-related GTPase from plants 1 (ROP1) exhibits oscillatory activation behavior at the apical plasma membrane of growing pollen tubes; however, a similar oscillation in Rho GTPase activity has so far not been demonstrated in mammalian cells. We hypothesized that oscillations in Cdc42 activity might occur within NK cells as they interact with target cells. Through fluorescence lifetime imaging of a Cdc42 biosensor, we observed that in live NK cells forming immunological synapses with target cells, Cdc42 activity oscillated after exhibiting an initial increase. We used protein-protein interaction networks and structural databases to identify candidate proteins that controlled Cdc42 activity, leading to the design of a targeted short interfering RNA screen. The guanine nucleotide exchange factors RhoGEF6 and RhoGEF7 were necessary for Cdc42 activation within the NK cell immunological synapse. In addition, the kinase Akt and the p85α subunit of phosphoinositide 3-kinase (PI3K) were required for Cdc42 activation, the periodicity of the oscillation in Cdc42 activity, and the subsequent polarization of cytotoxic vesicles toward target cells. Given that PI3Ks are targets of tumor therapies, our findings suggest the need to monitor innate immune function during the course of targeted therapy against these enzymes.
Collapse
Affiliation(s)
- Leo M Carlin
- Richard Dimbleby Department of Cancer Research, King's College London, London SE1 1UL, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Alix E, Mukherjee S, Roy CR. Subversion of membrane transport pathways by vacuolar pathogens. ACTA ACUST UNITED AC 2011; 195:943-52. [PMID: 22123831 PMCID: PMC3241728 DOI: 10.1083/jcb.201105019] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mammalian phagocytes control bacterial infections effectively through phagocytosis, the process by which particles engulfed at the cell surface are transported to lysosomes for destruction. However, intracellular pathogens have evolved mechanisms to avoid this fate. Many bacterial pathogens use specialized secretion systems to deliver proteins into host cells that subvert signaling pathways controlling membrane transport. These bacterial effectors modulate the function of proteins that regulate membrane transport and alter the phospholipid content of membranes. Elucidating the biochemical function of these effectors has provided a greater understanding of how bacteria control membrane transport to create a replicative niche within the host and provided insight into the regulation of membrane transport in eukaryotic cells.
Collapse
Affiliation(s)
- Eric Alix
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
| | | | | |
Collapse
|
32
|
Malik-Kale P, Jolly CE, Lathrop S, Winfree S, Luterbach C, Steele-Mortimer O. Salmonella - at home in the host cell. Front Microbiol 2011; 2:125. [PMID: 21687432 PMCID: PMC3109617 DOI: 10.3389/fmicb.2011.00125] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 05/19/2011] [Indexed: 11/16/2022] Open
Abstract
The Gram-negative bacterium Salmonella enterica has developed an array of sophisticated tools to manipulate the host cell and establish an intracellular niche, for successful propagation as a facultative intracellular pathogen. While Salmonella exerts diverse effects on its host cell, only the cell biology of the classic “trigger”-mediated invasion process and the subsequent development of the Salmonella-containing vacuole have been investigated extensively. These processes are dependent on cohorts of effector proteins translocated into host cells by two type III secretion systems (T3SS), although T3SS-independent mechanisms of entry may be important for invasion of certain host cell types. Recent studies into the intracellular lifestyle of Salmonella have provided new insights into the mechanisms used by this pathogen to modulate its intracellular environment. Here we discuss current knowledge of Salmonella-host interactions including invasion and establishment of an intracellular niche within the host.
Collapse
Affiliation(s)
- Preeti Malik-Kale
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Disease, National Institute of Health Hamilton, MT, USA
| | | | | | | | | | | |
Collapse
|
33
|
Salmonella enterica serovar typhimurium invades fibroblasts by multiple routes differing from the entry into epithelial cells. Infect Immun 2010; 78:2700-13. [PMID: 20368348 DOI: 10.1128/iai.01389-09] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Fibroblasts are ubiquitous cells essential to tissue homeostasis. Despite their nonphagocytic nature, fibroblasts restrain replication of intracellular bacterial pathogens such as Salmonella enterica serovar Typhimurium. The extent to which the entry route of the pathogen determines this intracellular response is unknown. Here, we analyzed S. Typhimurium invasion in fibroblasts obtained from diverse origins, including primary cultures and stable nontransformed cell lines derived from normal tissues. Features distinct to the invasion of epithelial cells were found in all fibroblasts tested. In some fibroblasts, bacteria lacking the type III secretion system encoded in the Salmonella pathogenicity island 1 displayed significant invasion rates and induced the formation of lamellipodia and filopodia at the fibroblast-bacteria contact site. Other bacterial invasion traits observed in fibroblasts were the requirement of phosphatidylinositol 3-kinase, mitogen-activated protein kinase MEK1, and both actin filaments and microtubules. RNA interference studies showed that different Rho family GTPases are targeted by S. Typhimurium to enter into distinct fibroblasts. Rac1 and Cdc42 knockdown affected invasion of normal rat kidney fibroblasts, whereas none of the GTPases tested (Rac1, Cdc42, RhoA, or RhoG) was essential for invasion of immortalized human foreskin fibroblasts. Collectively, these data reveal a marked diversity in the modes used by S. Typhimurium to enter into fibroblasts.
Collapse
|
34
|
Furuta N, Fujita N, Noda T, Yoshimori T, Amano A. Combinational soluble N-ethylmaleimide-sensitive factor attachment protein receptor proteins VAMP8 and Vti1b mediate fusion of antimicrobial and canonical autophagosomes with lysosomes. Mol Biol Cell 2010; 21:1001-10. [PMID: 20089838 PMCID: PMC2836953 DOI: 10.1091/mbc.e09-08-0693] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autophagy plays a crucial role in host defense, termed antimicrobial autophagy (xenophagy), as it functions to degrade intracellular foreign microbial invaders such as group A Streptococcus (GAS). Xenophagosomes undergo a stepwise maturation process consisting of a fusion event with lysosomes, after which the cargoes are degraded. However, the molecular mechanism underlying xenophagosome/lysosome fusion remains unclear. We examined the involvement of endocytic soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) in xenophagosome/lysosome fusion. Confocal microscopic analysis showed that SNAREs, including vesicle-associated membrane protein (VAMP)7, VAMP8, and vesicle transport through interaction with t-SNAREs homologue 1B (Vti1b), colocalized with green fluorescent protein-LC3 in xenophagosomes. Knockdown of Vti1b and VAMP8 with small interfering RNAs disturbed the colocalization of LC3 with lysosomal membrane protein (LAMP)1. The invasive efficiency of GAS into cells was not altered by knockdown of VAMP8 or Vti1b, whereas cellular bactericidal efficiency was significantly diminished, indicating that antimicrobial autophagy was functionally impaired. Knockdown of Vti1b and VAMP8 also disturbed colocalization of LC3 with LAMP1 in canonical autophagy, in which LC3-II proteins were negligibly degraded. In contrast, knockdown of Syntaxin 7 and Syntaxin 8 showed little effect on the autophagic fusion event. These findings strongly suggest that the combinational SNARE proteins VAMP8 and Vti1b mediate the fusion of antimicrobial and canonical autophagosomes with lysosomes, an essential event for autophagic degradation.
Collapse
Affiliation(s)
- Nobumichi Furuta
- Department of Oral Frontier Biology, Osaka University Graduate School of Dentistry, Suita-Osaka 565-0871, Japan
| | | | | | | | | |
Collapse
|
35
|
Ho YHS, Cai DT, Huang D, Wang CC, Wong SH. Caspases regulate VAMP-8 expression and phagocytosis in dendritic cells. Biochem Biophys Res Commun 2009; 387:371-5. [PMID: 19607812 DOI: 10.1016/j.bbrc.2009.07.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 07/08/2009] [Indexed: 01/13/2023]
Abstract
During an inflammation and upon encountering pathogens, immature dendritic cells (DC) undergo a maturation process to become highly efficient in presenting antigens. This transition from immature to mature state is accompanied by various physiological, functional and morphological changes including reduction of caspase activity and inhibition of phagocytosis in the mature DC. Caspases are cysteine proteases which play essential roles in apoptosis, necrosis and inflammation. Here, we demonstrate that VAMP-8, (a SNARE protein of the early/late endosomes) which has been shown previously to inhibit phagocytosis in DC, is a substrate of caspases. Furthermore, we identified two putative conserved caspase recognition/cleavage sites on the VAMP-8 protein. Consistent with the up-regulation of VAMP-8 expression upon treatment with caspase inhibitor (CI), immature DC treated with CI exhibits lower phagocytosis activity. Thus, our results highlight the role of caspases in regulating VAMP-8 expression and subsequently phagocytosis during maturation of DC.
Collapse
Affiliation(s)
- Yong Hou Sunny Ho
- Department of Microbiology, Laboratory of Membrane Trafficking and Immunoregulation, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Republic of Singapore
| | | | | | | | | |
Collapse
|
36
|
Weber SS, Ragaz C, Hilbi H. Pathogen trafficking pathways and host phosphoinositide metabolism. Mol Microbiol 2009; 71:1341-52. [PMID: 19208094 DOI: 10.1111/j.1365-2958.2009.06608.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phosphoinositide (PI) glycerolipids are key regulators of eukaryotic signal transduction, cytoskeleton architecture and membrane dynamics. The host cell PI metabolism is targeted by intracellular bacterial pathogens, which evolved intricate strategies to modulate uptake processes and vesicle trafficking pathways. Upon entering eukaryotic host cells, pathogenic bacteria replicate in distinct vacuoles or in the host cytoplasm. Vacuolar pathogens manipulate PI levels to mimic or modify membranes of subcellular compartments and thereby establish their replicative niche. Legionella pneumophila, Brucella abortus, Mycobacterium tuberculosis and Salmonella enterica translocate effector proteins into the host cell, some of which anchor to the vacuolar membrane via PIs or enzymatically turnover PIs. Cytoplasmic pathogens target PI metabolism at the plasma membrane, thus modulating their uptake and antiapoptotic signalling pathways. Employing this strategy, Shigella flexneri directly injects a PI-modifying effector protein, while Listeria monocytogenes exploits PI metabolism indirectly by binding to transmembrane receptors. Thus, regardless of the intracellular lifestyle of the pathogen, PI metabolism is critically involved in the interactions with host cells.
Collapse
Affiliation(s)
- Stefan S Weber
- Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | | | | |
Collapse
|
37
|
McGhie EJ, Brawn LC, Hume PJ, Humphreys D, Koronakis V. Salmonella takes control: effector-driven manipulation of the host. Curr Opin Microbiol 2009; 12:117-24. [PMID: 19157959 PMCID: PMC2647982 DOI: 10.1016/j.mib.2008.12.001] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 11/27/2008] [Accepted: 12/01/2008] [Indexed: 01/20/2023]
Abstract
Salmonella pathogenesis relies upon the delivery of over thirty specialised effector proteins into the host cell via two distinct type III secretion systems. These effectors act in concert to subvert the host cell cytoskeleton, signal transduction pathways, membrane trafficking and pro-inflammatory responses. This allows Salmonella to invade non-phagocytic epithelial cells, establish and maintain an intracellular replicative niche and, in some cases, disseminate to cause systemic disease. This review focuses on the actions of the effectors on their host cell targets during each stage of Salmonella infection.
Collapse
|
38
|
Function and dysfunction of the PI system in membrane trafficking. EMBO J 2008; 27:2457-70. [PMID: 18784754 PMCID: PMC2536629 DOI: 10.1038/emboj.2008.169] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 08/05/2008] [Indexed: 02/01/2023] Open
Abstract
The phosphoinositides (PIs) function as efficient and finely tuned switches that control the assembly–disassembly cycles of complex molecular machineries with key roles in membrane trafficking. This important role of the PIs is mainly due to their versatile nature, which is in turn determined by their fast metabolic interconversions. PIs can be tightly regulated both spatially and temporally through the many PI kinases (PIKs) and phosphatases that are distributed throughout the different intracellular compartments. In spite of the enormous progress made in the past 20 years towards the definition of the molecular details of PI–protein interactions and of the regulatory mechanisms of the individual PIKs and phosphatases, important issues concerning the general principles of the organisation of the PI system and the coordination of the different PI-metabolising enzymes remain to be addressed. The answers should come from applying a systems biology approach to the study of the PI system, through the integration of analyses of the protein interaction data of the PI enzymes and the PI targets with those of the ‘phenomes' of the genetic diseases that involve these PI-metabolising enzymes.
Collapse
|
39
|
Ho YHS, Cai DT, Wang CC, Huang D, Wong SH. Vesicle-associated membrane protein-8/endobrevin negatively regulates phagocytosis of bacteria in dendritic cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:3148-57. [PMID: 18292538 DOI: 10.4049/jimmunol.180.5.3148] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Phagocytosis is a specialized mechanism used by mammalian cells, particularly the cells of the immune system, such as dendritic cells (DC) and macrophages, to protect the host against infection. The process involves a complex cascade of pathways, from the ligation of surface receptors of phagocytes with components of the microorganism's surface, formation of phagosomes and subsequently phagolysosomes, to the eventual presentation of foreign Ags. Vesicle-associated membrane protein (VAMP)-8/endobrevin has been shown previously to function in the endocytic pathways. Our results showed that VAMP-8 colocalized with lysosome-associated membrane protein-2, and a significant amount of VAMP-8 was recruited to the phagosomes during bacterial ingestion. However, overexpression of VAMP-8 significantly inhibited phagocytosis in DC. We also found that the phagocytic activity of VAMP-8-/- DC was significantly higher than wild-type VAMP-8+/+ DC, thus further confirming that VAMP-8 negatively regulates phagocytosis in immature DC.
Collapse
Affiliation(s)
- Yong Hou Sunny Ho
- Laboratory of Membrane Trafficking and Immunoregulation Research, Department of Microbiology, Immunology Program, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore
| | | | | | | | | |
Collapse
|
40
|
Steele-Mortimer O. The Salmonella-containing vacuole: moving with the times. Curr Opin Microbiol 2008; 11:38-45. [PMID: 18304858 DOI: 10.1016/j.mib.2008.01.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 12/26/2007] [Accepted: 01/12/2008] [Indexed: 10/22/2022]
Abstract
Salmonella pathogenesis is dependent on its ability to invade and replicate within host cells. Following invasion the bacteria remain within a modified phagosome known as the Salmonella-containing vacuole (SCV), within which they will survive and replicate. Invasion and SCV biogenesis are dependent on two Type III secretion systems, T3SS1 and T3SS2, which are used to translocate distinct cohorts of bacterial effector proteins into the host cell. Elucidating the roles of individual effector proteins in SCV biogenesis has proven difficult but several distinct themes are now emerging and it is apparent that SCV biogenesis is an extremely dynamic process involving; extensive membrane remodeling, interactions with the endolysosomal pathway, actin rearrangements and microtubule-based movement and tubule extension.
Collapse
Affiliation(s)
- Olivia Steele-Mortimer
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA.
| |
Collapse
|