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Purdie AC, Plain KM, Pooley H, Begg DJ, de Silva K, Whittington RJ. Correlates of vaccine protection against Mycobacterium avium sub-species paratuberculosis infection revealed in a transcriptomic study of responses in Gudair ® vaccinated sheep. Front Vet Sci 2022; 9:1004237. [PMID: 36504842 PMCID: PMC9729357 DOI: 10.3389/fvets.2022.1004237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 11/07/2022] [Indexed: 11/25/2022] Open
Abstract
A critical hindrance in the development of effective vaccine strategies to combat infectious disease is lack of knowledge about correlates of protection and of the host responses necessary for successful adaptive immunity. Often vaccine formulations are developed by stepwise experimentation, with incomplete investigation of the fundamental mechanisms of protection. Gudair® is a commercially available vaccine registered for use in sheep and goats for controlling spread of Mycobacterium avium sub-species paratuberculosis (MAP) infections and reduces mortality by up to 90%. Here, using an experimental infection model in sheep, we have utilized a transcriptomics approach to identify white blood cell gene expression changes in vaccinated, MAP-exposed Merino sheep with a protective response in comparison to those vaccinated animals that failed to develop immunity to MAP infection. This methodology facilitated an overview of gene-associated functional pathway adaptations using an in-silico analysis approach. We identified a group of genes that were activated in the vaccine-protected animals and confirmed stability of expression in samples obtained from naturally exposed commercially maintained sheep. We propose these genes as correlates of vaccine induced protection.
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Salinas RP, Ortiz Flores RM, Distel JS, Aguilera MO, Colombo MI, Berón W. Coxiella burnetii Phagocytosis Is Regulated by GTPases of the Rho Family and the RhoA Effectors mDia1 and ROCK. PLoS One 2015; 10:e0145211. [PMID: 26674774 PMCID: PMC4682630 DOI: 10.1371/journal.pone.0145211] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 12/01/2015] [Indexed: 01/09/2023] Open
Abstract
The GTPases belonging to the Rho family control the actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, the etiologic agent of Q fever, is internalized by the host´s cells in an actin-dependent manner. Nevertheless, the molecular mechanism involved in this process has been poorly characterized. This work analyzes the role of different GTPases of the Rho family and some downstream effectors in the internalization of C. burnetii by phagocytic and non-phagocytic cells. The internalization of C. burnetii into HeLa and RAW cells was significantly inhibited when the cells were treated with Clostridium difficile Toxin B which irreversibly inactivates members of the Rho family. In addition, the internalization was reduced in HeLa cells that overexpressed the dominant negative mutants of RhoA, Rac1 or Cdc42 or that were knocked down for the Rho GTPases. The pharmacological inhibition or the knocking down of ROCK diminished bacterium internalization. Moreover, C. burnetii was less efficiently internalized in HeLa cells overexpressing mDia1-N1, a dominant negative mutant of mDia1, while the overexpression of the constitutively active mutant mDia1-ΔN3 increased bacteria uptake. Interestingly, when HeLa and RAW cells were infected, RhoA, Rac1 and mDia1 were recruited to membrane cell fractions. Our results suggest that the GTPases of the Rho family play an important role in C. burnetii phagocytosis in both HeLa and RAW cells. Additionally, we present evidence that ROCK and mDia1, which are downstream effectors of RhoA, are involved in that process.
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Affiliation(s)
- Romina P. Salinas
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Rodolfo M. Ortiz Flores
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Jesús S. Distel
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Milton O. Aguilera
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - María I. Colombo
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Walter Berón
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
- * E-mail:
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GODEK ML, SAMPSON JA, DUCHSHERER NL, McELWEE Q, GRAINGER DW. Rho GTPase protein expression and activation in murine monocytes/macrophages is not modulated by model biomaterial surfaces in serum-containing in vitro cultures. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 17:1141-1158. [PMID: 17235380 PMCID: PMC1776857 DOI: 10.1163/156856206778530731] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Rho GTPase cellular signaling cascade was investigated in pro-monocyte and (monocyte-)macrophage cells by examining GTPase expression and activation in serum-containing cultures on model biomaterials. Abundance of Rho GDI and the Rho GTPase proteins RhoA, Cdc42 and Rac1 was determined in cells grown on tissue culture polystyrene, polystyrene, poly-l-lactide and Teflon(®) AF surfaces. Protein expression was compared based on cell maturity (pro-monocyte to monocyte to macrophage lineages) and by model surface chemistry: Rho proteins were present in the majority of macrophage cells tested on model surfaces suggesting that a pool of Rho proteins is readily available for signaling events in response to numerous activating cues, including biomaterials surface encounter. Rho GTPase activation profiles in these cell lines indicate active Cdc42 and Rho proteins in RAW 264.7, Rac1 and Rho in J774A.1, and Cdc42 and Rac1 in IC-21 cell lines, respectively. Collectively, these proteins are known to play critical roles in all actin-based cytoskeletal rearrangement necessary for cell adhesion, spreading and motility, and remain important to establishing cellular responses required for foreign body reactions in vivo. Differences in Rho GTPase protein expression levels based on cell sourcing (primary versus secondary-derived cell source), or as a function of surface chemistry were insignificant. Rho GTPase expression profiles varied between pro-monocytic non-adherent precursor cells and mature adherent monocyte/macrophage cells. The active GTP-bound forms of the Rho GTPase proteins were detected from monocyte-macrophage cell lines RAW 264.7 and J774A.1 on all polymer surfaces, suggesting that while these proteins are central to cell adhesive behavior, differences in surface chemistry are insufficient to differentially regulate GTPase activation in these cell types. Active Cdc42 was detected from cells cultured on the more-polar tissue culture polystyrene and poly-l-lactide surfaces after several days, but absent from those grown on apolar polystyrene and Teflon(®) AF, indicating some surface influence on this GTPase in serum-containing cultures.
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Affiliation(s)
- M. L. GODEK
- Cell and Molecular Biology Program, Colorado State University,
Fort Collins, CO 80523-1872, USA
| | - J. A. SAMPSON
- Department of Chemistry, Colorado State University, Fort
Collins, CO 80523-1872, USA
| | - N. L. DUCHSHERER
- Department of Chemistry, Colorado State University, Fort
Collins, CO 80523-1872, USA
| | - Q. McELWEE
- Department of Chemistry, Colorado State University, Fort
Collins, CO 80523-1872, USA
| | - D. W. GRAINGER
- Cell and Molecular Biology Program, Colorado State University,
Fort Collins, CO 80523-1872, USA
- Department of Chemistry, Colorado State University, Fort
Collins, CO 80523-1872, USA
- *To whom correspondence should be addressed. E-mail:
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Groves E, Rittinger K, Amstutz M, Berry S, Holden DW, Cornelis GR, Caron E. Sequestering of Rac by the Yersinia effector YopO blocks Fcgamma receptor-mediated phagocytosis. J Biol Chem 2009; 285:4087-4098. [PMID: 19926792 DOI: 10.1074/jbc.m109.071035] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pathogenic Yersinia species neutralize innate immune mechanisms by injecting type three secretion effectors into immune cells, altering cell signaling. Our study elucidates how one of these effectors, YopO, blocks phagocytosis. We demonstrate using different phagocytic models that YopO specifically blocks Rac-dependent Fcgamma receptor internalization pathway but not complement receptor 3-dependent uptake, which is controlled by Rho activity. We show that YopO prevents Rac activation but does not affect Rac accumulation at the phagocytic cup. In addition, we show that plasma membrane localization and the guanine-nucleotide dissociation inhibitor (GDI)-like domain of YopO cooperate for maximal anti-phagocytosis. Although YopO has the same affinity for Rac1, Rac2, and RhoA in vitro, it selectively interacts with Rac isoforms in cells. This is due to the differential localization of the Rho family G proteins in resting cells; Rac isoforms partially exist as a GDI-free pool at the membrane of resting cells, whereas RhoA is trapped in the cytosol by RhoGDIalpha. We propose that YopO exploits this basic difference in localization and availability to selectively inhibit Rac-dependent phagocytosis.
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Affiliation(s)
- Eleanor Groves
- From the Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, United Kingdom.
| | - Katrin Rittinger
- the Division of Molecular Structure, National Institute for Medical Research, The Ridgeway, London NW7 1AA, United Kingdom, and
| | - Marlise Amstutz
- Infection Biology, Biozentrum, University of Basel, Klingenbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Sara Berry
- From the Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - David W Holden
- From the Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Guy R Cornelis
- Infection Biology, Biozentrum, University of Basel, Klingenbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Emmanuelle Caron
- From the Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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Hoffmann A, Hofmann F, Just I, Lehnardt S, Hanisch UK, Brück W, Kettenmann H, Ahnert-Hilger G, Höltje M. Inhibition of Rho-dependent pathways by Clostridium botulinum C3 protein induces a proinflammatory profile in microglia. Glia 2008; 56:1162-75. [PMID: 18442097 DOI: 10.1002/glia.20687] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Successful regeneration in the central nervous system crucially depends on the adequate environment. Microglia as brain immune-competent cells importantly contribute to this task by producing pro- and anti-inflammatory mediators. Any environmental change transforms these cells towards an activated phenotype, leading to major morphological, transcriptional and functional alterations. Rho GTPases affect multiple cellular properties, including the cytoskeleton, and C3 proteins are widely used to study their involvement. Especially C3bot from Clostridium botulinum has been considered to promote neuronal regeneration by changing Rho activity. Yet C3bot may exert cellular influences through alternative mechanisms. To determine the role of Rho-dependent pathways in microglia we investigated the influence of C3bot on functional properties of cultivated primary mouse microglial cells. Nanomolar concentrations of C3bot transformed microglia towards an activated phenotype and triggered the release of nitric oxide and several proinflammatory cyto- and chemokines. These inductions were not mediated by the ROCK-kinase pathway, since its selective inhibitors Y27632 and H1152 had no effect. C3-induced and Rho-mediated NO release was instead found to be under the control of NFkappaB, as revealed by treatment with the NFkappaB inhibitor PDTC. Thus, C3bot induces a proinflammatory response in microglia resembling the classical proinflammatory phenotype elicited by bacterial LPS. The findings are relevant for the use of C3bot in regenerative approaches.
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Affiliation(s)
- Anja Hoffmann
- Institut für Neuropathologie, Universität Göttingen, Germany
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Escaron CJ, Lees DM, Tewari R, Smith DF, Caron E. A simple, robust and versatile method to characterise intracellular parasitism. Mol Biochem Parasitol 2007; 153:72-6. [PMID: 17303261 DOI: 10.1016/j.molbiopara.2007.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 12/15/2006] [Accepted: 01/09/2007] [Indexed: 11/19/2022]
Affiliation(s)
- Claire J Escaron
- Division of Cell and Molecular Biology, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
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Braun V, Fraisier V, Raposo G, Hurbain I, Sibarita JB, Chavrier P, Galli T, Niedergang F. TI-VAMP/VAMP7 is required for optimal phagocytosis of opsonised particles in macrophages. EMBO J 2004; 23:4166-76. [PMID: 15470500 PMCID: PMC524391 DOI: 10.1038/sj.emboj.7600427] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 09/06/2004] [Indexed: 01/17/2023] Open
Abstract
Phagocytosis relies on extension of plasmalemmal pseudopods generated by focal actin polymerisation and delivery of membranes from intracellular pools. Here we show that compartments of the late endocytic pathway, bearing the tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP/VAMP7), are recruited upon particle binding and undergo exocytosis before phagosome sealing in macrophages during Fc receptor (FcR)-mediated phagocytosis. Expression of the dominant-negative amino-terminal domain of TI-VAMP or depletion of TI-VAMP with small interfering RNAs inhibited phagocytosis mediated by Fc or complement receptors. In addition, inhibition of TI-VAMP activity led to a reduced exocytosis of late endocytic vesicles and this resulted in an early blockade of pseudopod extension, as observed by scanning electron microscopy. Therefore, TI-VAMP defines a new pathway of membrane delivery required for optimal FcR-mediated phagocytosis.
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Affiliation(s)
- Virginie Braun
- Membrane and Cytoskeleton Dynamics group, UMR144 CNRS-Institut Curie, Paris, France
| | - Vincent Fraisier
- Digital Imaging Platform, UMR144 CNRS-Institut Curie, Paris, France
| | - Graça Raposo
- Electron Microscopy Group, UMR144 CNRS-Institut Curie, Paris, France
| | - Ilse Hurbain
- Electron Microscopy Group, UMR144 CNRS-Institut Curie, Paris, France
| | | | - Philippe Chavrier
- Membrane and Cytoskeleton Dynamics group, UMR144 CNRS-Institut Curie, Paris, France
| | - Thierry Galli
- Membrane Traffic and Neuronal Plasticity, INSERM U536, Institut du Fer-à-Moulin, Paris, France
| | - Florence Niedergang
- Membrane and Cytoskeleton Dynamics group, UMR144 CNRS-Institut Curie, Paris, France
- UMR144 CNRS-Institut Curie, 26, rue d'Ulm, 75248 Paris cedex 05, France. Tel.: +33 1 42 34 63 67; Fax: +33 1 42 34 63 77; E-mail:
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8
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Scott G, Leopardi S, Parker L, Babiarz L, Seiberg M, Han R. The proteinase-activated receptor-2 mediates phagocytosis in a Rho-dependent manner in human keratinocytes. J Invest Dermatol 2003; 121:529-41. [PMID: 12925212 DOI: 10.1046/j.1523-1747.2003.12427.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent work shows that the G-protein-coupled receptor proteinase activated receptor-2 activates signals that stimulate melanosome uptake in keratinocytes in vivo and in vitro. The Rho family of GTP-binding proteins is involved in cytoskeletal remodeling during phagocytosis. We show that proteinase-activated receptor-2 mediated phagocytosis in human keratinocytes is Rho dependent and that proteinase-activated receptor-2 signals to activate Rho. In contrast, Rho activity did not affect either proteinase-activated receptor-2 activity or mRNA and protein levels. We explored the signaling mechanisms of proteinase-activated receptor-2 mediated Rho activation in human keratinocytes and show that activation of proteinase-activated receptor-2, either through specific proteinase-activated receptor-2 activating peptides or through trypsinization, elevates cAMP in keratinocytes. Proteinase-activated receptor-2 mediated Rho activation was pertussis toxin insensitive and independent of the protein kinase A signaling pathway. These data are the first to show that proteinase-activated receptor-2 mediated phagocytosis is Rho dependent and that proteinase-activated receptor-2 signals to Rho and cAMP in keratinocytes. Because phagocytosis of melanosomes is recognized as an important mechanism for melanosome transfer to keratinocytes, these results suggest that Rho is a critical signaling intermediate in melanosome uptake in keratinocytes.
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Affiliation(s)
- Glynis Scott
- Department of Dermatology, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14618, USA.
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Niedergang F, Colucci-Guyon E, Dubois T, Raposo G, Chavrier P. ADP ribosylation factor 6 is activated and controls membrane delivery during phagocytosis in macrophages. J Cell Biol 2003; 161:1143-50. [PMID: 12810696 PMCID: PMC2172982 DOI: 10.1083/jcb.200210069] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Engulfment of particles by phagocytes is induced by their interaction with specific receptors on the cell surface, which leads to actin polymerization and the extension of membrane protrusions to form a closed phagosome. Membrane delivery from internal pools is considered to play an important role in pseudopod extension during phagocytosis. Here, we report that endogenous ADP ribosylation factor 6 (ARF6), a small GTP-binding protein, undergoes a sharp and transient activation in macrophages when phagocytosis was initiated via receptors for the Fc portion of immunoglobulins (FcRs). A dominant-negative mutant of ARF6 (T27N mutation) dramatically affected FcR-mediated phagocytosis. Expression of ARF6-T27N lead to a reduction in the focal delivery of vesicle-associated membrane protein 3+ endosomal recycling membranes at phagocytosis sites, whereas actin polymerization was unimpaired. This resulted in an early blockade in pseudopod extension and accumulation of intracellular vesicles, as observed by electron microscopy. We conclude that ARF6 is a major regulator of membrane recycling during phagocytosis.
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Affiliation(s)
- Florence Niedergang
- Membrane and Cytoskeleton Dynamics Laboratory, UMR144 CNRS, Institut Curie, 26 rue d'Ulm, F-75248 Paris cedex 05, France.
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Zhang Z, Wu C, Wang S, Huang W, Zhou Z, Ying K, Xie Y, Mao Y. Cloning and characterization of ARHGAP12, a novel human rhoGAP gene. Int J Biochem Cell Biol 2002; 34:325-31. [PMID: 11854031 DOI: 10.1016/s1357-2725(01)00134-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Rho GTPase activating proteins (GAPs) stimulate the intrinsic GTP hydrolysis activity of Rho family proteins. Here we report the cloning of two splice variants of a novel gene named ARHGAP12 (access number), which has an ORF of 2541bp. Profilescan search result showed that its putative protein contains five domains: rhoGAP, SH3, PH and two WW domains. ARHGAP12 is located in chromosome 10pter-cen and consists of 20 exons according to the Blastn result against high throughput genomic sequences (htgs). Reverse transcription PCR and Northern blot indicates that it ubiquitously expresses in human tissues as well as tumor cell lines, suggesting its basic roles in cells.
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Affiliation(s)
- Zhen Zhang
- School of Life Science, State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, PR China
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11
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Patel JC, Hall A, Caron E. Vav regulates activation of Rac but not Cdc42 during FcgammaR-mediated phagocytosis. Mol Biol Cell 2002; 13:1215-26. [PMID: 11950933 PMCID: PMC102263 DOI: 10.1091/mbc.02-01-0002] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Phagocytosis is the process whereby cells direct the spatially localized, receptor-driven engulfment of particulate materials. It proceeds via remodeling of the actin cytoskeleton and shares many of the core cytoskeletal components involved in adhesion and migration. Small GTPases of the Rho family have been widely implicated in coordinating actin dynamics in response to extracellular signals and during diverse cellular processes, including phagocytosis, yet the mechanisms controlling their recruitment and activation are not known. We show herein that in response to ligation of Fc receptors for IgG (FcgammaR), the guanine nucleotide exchange factor Vav translocates to nascent phagosomes and catalyzes GTP loading on Rac, but not Cdc42. The Vav-induced Rac activation proceeds independently of Cdc42 function, suggesting distinct roles for each GTPase during engulfment. Moreover, inhibition of Vav exchange activity or of Cdc42 activity does not prevent Rac recruitment to sites of particle attachment. We conclude that Rac is recruited to Fcgamma membrane receptors in its inactive, GDP-bound state and that Vav regulates phagocytosis through subsequent catalysis of GDP/GTP exchange on Rac.
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Affiliation(s)
- Jayesh C Patel
- Medical Research Council Laboratory for Molecular Cell Biology, Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
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12
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Abstract
The cytotoxic necrotizing factor 1, from uropathogenic Escherichia coli, is the paradigm of Rho-GTPases-activating bacterial toxins. CNF1 is a MW 108kDa A-B protein toxin divided into three domains which are implicated in the three steps of the intoxication process. The N-terminal domain contains the cell receptor function and binds with high affinity to a cell receptor not yet identified. Binding of the toxin is followed by its internalization by endocytosis and its transport into late endosomes. The middle toxin domain contains two hydophobic helices which allow translocation of the toxin across the membrane upon acidification in late endosomes. Finally the carboxy-terminal domain of CNF1 is an enzyme which deamidates Rho-GTP-binding proteins (Rho, Rac and Cdc42) glutamine 63 (for Rho) or glutamine 61 (for Rac and Cdc42). Deamidation of glutamine 63/61 blocks the intrinsic or the GTPase activating protein (GAP)-induced hydrolysis of GTP leading to the permanent activation of the GTPase. Activation of Rho GTPases by CNF1 induces a profound reorganization of the cell actin cytoskeleton. By its properties on Rho GTPases CNF1 is to date an invaluable tool for cell biology studies.
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Affiliation(s)
- P Boquet
- INSERM U452, Faculty of Medicine, 06107, Nice, France.
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Ellson CD, Anderson KE, Morgan G, Chilvers ER, Lipp P, Stephens LR, Hawkins PT. Phosphatidylinositol 3-phosphate is generated in phagosomal membranes. Curr Biol 2001; 11:1631-5. [PMID: 11676926 DOI: 10.1016/s0960-9822(01)00447-x] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Phagocytic cells such as neutrophils and macrophages engulf and destroy invading microorganisms. After internalization, material captured within the phagosomal membrane is destroyed by a complex process of coordinated delivery of digestive enzymes and reactive oxygen species. Several endosomal, lysosomal, and oxidase components expected to participate in these events have recently been shown to bind PtdIns3P, suggesting that this lipid may play a role in this process. We used live, digital fluorescence imaging of RAW 264.7 cells stably expressing either a PtdIns3P binding GFP-PX domain or a GFP-FYVE domain to visualize changes in the levels and subcellular localization of PtdIns3P during phagocytic uptake of IgG-opsonized zymosan particles. Very similar results were obtained using both PtdIns3P probes. The basal distribution of each PtdIns3P probe was partially cytosolic and partially localized to EEA-1-positive endosomal structures. Within about 2-3 min of zymosan attachment and concomitant with the closure of the phagosomal membrane, GFP-positive vesicles moved toward and attached to a localized area of the phagosome. A dramatic, transient accumulation of GFP probe around the entire phagosome rapidly ensued, accompanied by a transient drop in cytosolic GFP fluorescence. The magnitude and timing of this rise in PtdIns3P clearly suggest that it is an ideal candidate for controlling the early stages of phagosomal maturation.
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Affiliation(s)
- C D Ellson
- Inositide Laboratory, The Babraham Institute, Babraham, CB2 4AT, Cambridge, United Kingdom
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