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Machin DC, Williamson DJ, Fisher P, Miller VJ, Arnott ZLP, Stevenson CME, Wildsmith GC, Ross JF, Wasson CW, Macdonald A, Andrews BI, Ungar D, Turnbull WB, Webb ME. Sortase-Modified Cholera Toxoids Show Specific Golgi Localization. Toxins (Basel) 2024; 16:194. [PMID: 38668619 PMCID: PMC11054894 DOI: 10.3390/toxins16040194] [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: 02/08/2024] [Revised: 03/18/2024] [Accepted: 04/09/2024] [Indexed: 04/29/2024] Open
Abstract
Cholera toxoid is an established tool for use in cellular tracing in neuroscience and cell biology. We use a sortase labeling approach to generate site-specific N-terminally modified variants of both the A2-B5 heterohexamer and B5 pentamer forms of the toxoid. Both forms of the toxoid are endocytosed by GM1-positive mammalian cells, and while the heterohexameric toxoid was principally localized in the ER, the B5 pentamer showed an unexpectedly specific localization in the medial/trans-Golgi. This study suggests a future role for specifically labeled cholera toxoids in live-cell imaging beyond their current applications in neuronal tracing and labeling of lipid rafts in fixed cells.
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Affiliation(s)
- Darren C. Machin
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Daniel J. Williamson
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Peter Fisher
- Department of Biology, University of York, York YO10 5DD, UK
| | | | - Zoe L. P. Arnott
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Charlotte M. E. Stevenson
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Gemma C. Wildsmith
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - James F. Ross
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Christopher W. Wasson
- Faculty of Biological Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK (A.M.)
| | - Andrew Macdonald
- Faculty of Biological Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK (A.M.)
| | - Benjamin I. Andrews
- GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, UK
| | - Daniel Ungar
- Department of Biology, University of York, York YO10 5DD, UK
| | - W. Bruce Turnbull
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
| | - Michael E. Webb
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (D.C.M.)
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2
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Effects of periodic mechanical stress on cytoskeleton dependent lipid raft-induced integrin ɑ1 activation in rat nucleus pulposus cells. J Mol Histol 2023; 54:67-75. [PMID: 36719565 PMCID: PMC9908706 DOI: 10.1007/s10735-023-10112-1] [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: 11/07/2021] [Accepted: 01/05/2023] [Indexed: 02/01/2023]
Abstract
Extracellular matrix (ECM) production and nucleus pulposus (NP) cell migration increase under periodic mechanical stress (PMS), but the underpinning regulatory mechanism remains unclear. This work aimed to examine the regulatory effects of cytoskeleton-lipid raft-integrin α1 signaling in NP cells exposed to PMS. Briefly, In NP cells, cytoskeleton rearrangement, lipid raft aggregation and integrin α1 expression in the stress and control groups were assessed by immunofluorescent staining and immunoblot. In addition, cell migration and ECM gene expression were detected by a scratch test and quantitative reverse transcription polymerase chain reaction (qRT‑PCR), respectively. As a result, PMS up-regulated ECM gene expression and enhanced NP cell migration (both P < 0.05), accompanied by increased integrin α1, lipid raft, caveolin-3, F-actin and β-tubulin amounts. Pretreatment with the lipid raft inhibitor methyl-β-cyclodextrin (MβCD) or small interfering RNA (siRNA) targeting caveolin-3 resulted in decreased ECM mRNA synthesis and cell migration induced by PMS (both P < 0.05); meanwhile, integrin α1 expression was also reduced. F-actin and β-tubulin inhibition by cytochalasin D and colchicine, respectively, not only reduced ECM mRNA synthesis and cell migration (both P < 0.05), but also disrupted lipid raft and caveolin-3 amount increases induced by PMS in NP cells. In conclusion, PMS promotes ECM mRNA up-regulation and cell migration through the cytoskeleton-lipid raft-integrin α1 signaling pathway, inhibiting cytoskeleton and lipid rafts could block the cellular effects.
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Ouahed J, Kelsen JR, Spessott WA, Kooshesh K, Sanmillan ML, Dawany N, Sullivan KE, Hamilton KE, Slowik V, Nejentsev S, Neves JF, Flores H, Chung WK, Wilson A, Anyane-Yeboa K, Wou K, Jain P, Field M, Tollefson S, Dent MH, Li D, Naito T, McGovern DPB, Kwong AC, Taliaferro F, Ordovas-Montanes J, Horwitz BH, Kotlarz D, Klein C, Evans J, Dorsey J, Warner N, Elkadri A, Muise AM, Goldsmith J, Thompson B, Engelhardt KR, Cant AJ, Hambleton S, Barclay A, Toth-Petroczy A, Vuzman D, Carmichael N, Bodea C, Cassa CA, Devoto M, Maas RL, Behrens EM, Giraudo CG, Snapper SB. Variants in STXBP3 are Associated with Very Early Onset Inflammatory Bowel Disease, Bilateral Sensorineural Hearing Loss and Immune Dysregulation. J Crohns Colitis 2021; 15:1908-1919. [PMID: 33891011 PMCID: PMC8575043 DOI: 10.1093/ecco-jcc/jjab077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND AIMS Very early onset inflammatory bowel disease [VEOIBD] is characterized by intestinal inflammation affecting infants and children less than 6 years of age. To date, over 60 monogenic aetiologies of VEOIBD have been identified, many characterized by highly penetrant recessive or dominant variants in underlying immune and/or epithelial pathways. We sought to identify the genetic cause of VEOIBD in a subset of patients with a unique clinical presentation. METHODS Whole exome sequencing was performed on five families with ten patients who presented with a similar constellation of symptoms including medically refractory infantile-onset IBD, bilateral sensorineural hearing loss and, in the majority, recurrent infections. Genetic aetiologies of VEOIBD were assessed and Sanger sequencing was performed to confirm novel genetic findings. Western analysis on peripheral blood mononuclear cells and functional studies with epithelial cell lines were employed. RESULTS In each of the ten patients, we identified damaging heterozygous or biallelic variants in the Syntaxin-Binding Protein 3 gene [STXBP3], a protein known to regulate intracellular vesicular trafficking in the syntaxin-binding protein family of molecules, but not associated to date with either VEOIBD or sensorineural hearing loss. These mutations interfere with either intron splicing or protein stability and lead to reduced STXBP3 protein expression. Knock-down of STXBP3 in CaCo2 cells resulted in defects in cell polarity. CONCLUSION Overall, we describe a novel genetic syndrome and identify a critical role for STXBP3 in VEOIBD, sensorineural hearing loss and immune dysregulation.
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Affiliation(s)
- Jodie Ouahed
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Judith R Kelsen
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Waldo A Spessott
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Kameron Kooshesh
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Maria L Sanmillan
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Noor Dawany
- Department of Biomedical Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Kathleen E Sullivan
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kathryn E Hamilton
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Voytek Slowik
- Department of Medicine, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sergey Nejentsev
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Mercy Kansas City, Kansas City, MO, 64108, USA.,Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - João Farela Neves
- Department of Molecular Cell Biology and Immunology, Amsterdam University Medical Centers, Amsterdam, the Netherlands.,Primary Immunodeficiencies Unit; Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Helena Flores
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, Lisbon, 1150, Portugal
| | - Wendy K Chung
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Ashley Wilson
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Kwame Anyane-Yeboa
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Karen Wou
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Preti Jain
- Department of Pediatrics, Columbia University Medical Center, New York, NY, 10032, USA.,Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
| | - Michael Field
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Sophia Tollefson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Maiah H Dent
- Department of Genetics, Yale University, New Haven, CT, 06510, USA
| | - Dalin Li
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Takeo Naito
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Dermot P B McGovern
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Andrew C Kwong
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Faith Taliaferro
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Jose Ordovas-Montanes
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Program in Immunology, Harvard Medical School, Boston, MA, 02115, USA.,Harvard Stem Cell Institute, Cambridge, MA, 02138, USA
| | - Bruce H Horwitz
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Division of Emergency Medicine, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Daniel Kotlarz
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Dr. von Hauner Children's Hospital, Department of Pediatrics, University Hospital LMU Munich, Munich, 80337, Germany
| | - Christoph Klein
- Dr. von Hauner Children's Hospital, Department of Pediatrics, University Hospital LMU Munich, Munich, 80337, Germany
| | - Jonathan Evans
- Department of Pediatrics, Nemours Children's Specialty Care, Jacksonville, FL 32207, USA
| | - Jill Dorsey
- Department of Pediatrics, Nemours Children's Specialty Care, Jacksonville, FL 32207, USA
| | - Neil Warner
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Abdul Elkadri
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Aleixo M Muise
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Jeffrey Goldsmith
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Benjamin Thompson
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK
| | - Karin R Engelhardt
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK
| | - Andrew J Cant
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK.,Children's Immunology Service, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, NE1 4LP, UK
| | - Sophie Hambleton
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK.,Children's Immunology Service, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, NE1 4LP, UK
| | - Andrew Barclay
- Department of Paediatric Gastroenterology, Royal Hospital for Children, Glasgow, G51 4TF, UK
| | - Agnes Toth-Petroczy
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
| | - Dana Vuzman
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Nikkola Carmichael
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Corneliu Bodea
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Christopher A Cassa
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Marcella Devoto
- Division of Human Genetics, The Children's Hospital of Philadelphia, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Translational and Precision Medicine, University Sapienza, Rome 00185, Italy.,CNR-IRGB, Cagliari 09042, Italy
| | - Richard L Maas
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Edward M Behrens
- Division of Rheumatology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Claudio G Giraudo
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Scott B Snapper
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Division of Gastroenterology, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
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Kenworthy AK, Schmieder SS, Raghunathan K, Tiwari A, Wang T, Kelly CV, Lencer WI. Cholera Toxin as a Probe for Membrane Biology. Toxins (Basel) 2021; 13:543. [PMID: 34437414 PMCID: PMC8402489 DOI: 10.3390/toxins13080543] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/23/2021] [Accepted: 07/29/2021] [Indexed: 12/26/2022] Open
Abstract
Cholera toxin B-subunit (CTxB) has emerged as one of the most widely utilized tools in membrane biology and biophysics. CTxB is a homopentameric stable protein that binds tightly to up to five GM1 glycosphingolipids. This provides a robust and tractable model for exploring membrane structure and its dynamics including vesicular trafficking and nanodomain assembly. Here, we review important advances in these fields enabled by use of CTxB and its lipid receptor GM1.
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Affiliation(s)
- Anne K. Kenworthy
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Stefanie S. Schmieder
- Division of Gastroenterology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Harvard Digestive Diseases Center, Boston, MA 02115, USA
| | - Krishnan Raghunathan
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA;
| | - Ajit Tiwari
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Ting Wang
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Christopher V. Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
| | - Wayne I. Lencer
- Division of Gastroenterology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Harvard Digestive Diseases Center, Boston, MA 02115, USA
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5
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Endocytic Internalization of Herpes Simplex Virus 1 in Human Keratinocytes at Low Temperature. J Virol 2021; 95:JVI.02195-20. [PMID: 33239453 PMCID: PMC7851553 DOI: 10.1128/jvi.02195-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) can adopt a variety of pathways to accomplish cellular internalization. In human keratinocytes representing the natural target cell of HSV-1, both direct plasma membrane fusion and endocytic uptake have been found. The impact of either pathway in successful infection, however, remains to be fully understood. To address the role of each internalization mode, we performed infection studies at low temperature as a tool to interfere with endocytic pathways. Interestingly, successful HSV-1 entry in primary human keratinocytes and HaCaT cells was observed even at 7°C, although delayed compared to infection at 37°C. Moreover, ex vivo infection of murine epidermis demonstrated that virus entry at 7°C is not only accomplished in cultured cells but also in tissue. Control experiments with cholera toxin B confirmed a block of endocytic uptake at 7°C. In addition, uptake of dextran by macropinosomes and phagocytic uptake of latex beads was also inhibited at 7°C. Infection of nectin-1-deficient murine keratinocytes affirmed that the entry at 7°C was receptor-dependent. Strikingly, the lysosomotropic agent, ammonium chloride, strongly inhibited HSV-1 entry suggesting a role for endosomal acidification. Ultrastructural analyses in turn revealed free capsids in the cytoplasm as well as virus particles in vesicles after infection at 7°C supporting both plasma membrane fusion and endocytic internalization as already observed at 37°C. Overall, entry of HSV-1 at 7°C suggests that the virus can efficiently adopt nectin-1-dependent unconventional vesicle uptake mechanisms in keratinocytes strengthening the role of endocytic internalization for successful infection.IMPORTANCE The human pathogen herpes simplex virus 1 (HSV-1) relies on multiple internalization pathways to initiate infection. Our focus is on the entry in human keratinocytes, the major in vivo target during primary and recurrent infection. While antivirals reduce the severity of clinical cases, there is no cure or vaccine against HSV. To develop strategies that interfere with virus penetration, we need to understand the various parameters and conditions that determine virus entry. Here, we addressed the impact of virus internalization via vesicles by blocking endocytic processes at low temperature. Intriguingly, we detected entry of HSV-1 even at 7°C which led to infection of primary keratinocytes and epidermal tissue. Moreover, electron microscopy of human keratinocytes at 7°C support that internalization is based on fusion of the viral envelope with the plasma membrane as well as vesicle membranes. These results provide novel insights into conditions that still allow endocytic internalization of HSV-1.
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6
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Sámano-Sánchez H, Gibson TJ. Mimicry of Short Linear Motifs by Bacterial Pathogens: A Drugging Opportunity. Trends Biochem Sci 2020; 45:526-544. [PMID: 32413327 DOI: 10.1016/j.tibs.2020.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/11/2022]
Abstract
Bacterial pathogens have developed complex strategies to successfully survive and proliferate within their hosts. Throughout the infection cycle, direct interaction with host cells occurs. Many bacteria have been found to secrete proteins, such as effectors and toxins, directly into the host cell with the potential to interfere with cell regulatory processes, either enzymatically or through protein-protein interactions (PPIs). Short linear motifs (SLiMs) are abundant peptide modules in cell signaling proteins. Here, we cover the reported examples of eukaryotic-like SLiM mimicry being used by pathogenic bacteria to hijack host cell machinery and discuss how drugs targeting SLiM-regulated cell signaling networks are being evaluated for interference with bacterial infections. This emerging anti-infective opportunity may become an essential contributor to antibiotic replacement strategies.
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Affiliation(s)
- Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, 69120 Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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7
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Vandeweerd JM, Hontoir F, De Knoop A, De Swert K, Nicaise C. Retrograde Neuroanatomical Tracing of Phrenic Motor Neurons in Mice. J Vis Exp 2018. [PMID: 29553523 DOI: 10.3791/56758] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic nerves innervating the respiratory diaphragm. In spinal cord slices, phrenic motor neurons cannot be identified from other motor neurons on morphological or biochemical criteria. We provide the description of procedures for visualizing phrenic motor neuron cell bodies in mice, following intrapleural injections of cholera toxin subunit beta (CTB) conjugated to a fluorophore. This fluorescent neuroanatomical tracer has the ability to be caught up at the diaphragm neuromuscular junction, be carried retrogradely along the phrenic axons and reach the phrenic cell bodies. Two methodological approaches of intrapleural CTB delivery are compared: transdiaphragmatic versus transthoracic injections. Both approaches are successful and result in similar number of CTB-labeled phrenic motor neurons. In conclusion, these techniques can be applied to visualize or quantify the phrenic motor neurons in various experimental studies such as those focused on the diaphragm-phrenic circuitry.
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8
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Park JH, Ahn JH, Choi SY, Cho JH, Lee TK, Kim IH, Lee JC, Choi JH, Hwang IK, Lee YJ, Lee E, Park S, Lim J, Seo K, Won MH. The location of projection neurons to the biceps brachii muscle in the telencephalon of the pigeon. Anat Histol Embryol 2017; 46:528-532. [DOI: 10.1111/ahe.12297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 08/06/2017] [Indexed: 01/16/2023]
Affiliation(s)
- J. H. Park
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology; Hallym University; Chuncheon South Korea
| | - J. H. Ahn
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology; Hallym University; Chuncheon South Korea
| | - S. Y. Choi
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology; Hallym University; Chuncheon South Korea
| | - J. H. Cho
- Department of Neurobiology; School of Medicine; Kangwon National University; Chuncheon South Korea
| | - T.-K. Lee
- Department of Neurobiology; School of Medicine; Kangwon National University; Chuncheon South Korea
| | - I. H. Kim
- Department of Neurobiology; School of Medicine; Kangwon National University; Chuncheon South Korea
| | - J.-C. Lee
- Department of Neurobiology; School of Medicine; Kangwon National University; Chuncheon South Korea
| | - J. H. Choi
- Department of Anatomy; College of Veterinary Medicine; Kangwon National University; Chuncheon South Korea
| | - I. K. Hwang
- Department of Anatomy and Cell Biology; College of Veterinary Medicine, and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
| | - Y. J. Lee
- Department of Emergency Medicine; Seoul Hospital; College of Medicine; Sooncheonhyang University; Seoul South Korea
| | - E. Lee
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
| | - S. Park
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
| | - J. Lim
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
| | - K. Seo
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
| | - M.-H. Won
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine and Research Institute for Veterinary Science; Seoul National University; Seoul South Korea
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9
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Saslowsky DE, Thiagarajah JR, McCormick BA, Lee JC, Lencer WI. Microbial sphingomyelinase induces RhoA-mediated reorganization of the apical brush border membrane and is protective against invasion. Mol Biol Cell 2016; 27:1120-30. [PMID: 26864627 PMCID: PMC4814219 DOI: 10.1091/mbc.e15-05-0293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 02/01/2016] [Indexed: 12/19/2022] Open
Abstract
Both commensal and pathogenic microbes that colonize the GI tract can synthesize and secrete spingomyelinase enzymes that cleave membrane sphingomyelin, leaving the ceramide component intact in the cell membrane. This study examines how this reaction affects the structure and function of host enterocytes and mucosal defense. The apical brush border membrane (BBM) of intestinal epithelial cells forms a highly structured and dynamic environmental interface that serves to regulate cellular physiology and block invasion by intestinal microbes and their products. How the BBM dynamically responds to pathogenic and commensal bacterial signals can define intestinal homeostasis and immune function. We previously found that in model intestinal epithelium, the conversion of apical membrane sphingomyelin to ceramide by exogenous bacterial sphingomyelinase (SMase) protected against the endocytosis and toxicity of cholera toxin. Here we elucidate a mechanism of action by showing that SMase induces a dramatic, reversible, RhoA-dependent alteration of the apical cortical F-actin network. Accumulation of apical membrane ceramide is necessary and sufficient to induce the actin phenotype, and this coincides with altered membrane structure and augmented innate immune function as evidenced by resistance to invasion by Salmonella.
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Affiliation(s)
- David E Saslowsky
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
| | - Jay R Thiagarajah
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
| | - Beth A McCormick
- Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655
| | - Jean C Lee
- Harvard Medical School, Boston, MA 02115 Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | - Wayne I Lencer
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
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10
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Aigal S, Claudinon J, Römer W. Plasma membrane reorganization: A glycolipid gateway for microbes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:858-71. [PMID: 25450969 DOI: 10.1016/j.bbamcr.2014.11.014] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/27/2014] [Accepted: 11/11/2014] [Indexed: 02/08/2023]
Abstract
Ligand-receptor interactions, which represent the core for cell signaling and internalization processes are largely affected by the spatial configuration of host cell receptors. There is a growing piece of evidence that receptors are not homogeneously distributed within the plasma membrane, but are rather pre-clustered in nanodomains, or clusters are formed upon ligand binding. Pathogens have evolved many strategies to evade the host immune system and to ensure their survival by hijacking plasma membrane receptors that are most often associated with lipid rafts. In this review, we discuss the early stage molecular and physiological events that occur following ligand binding to host cell glycolipids. The ability of various biological ligands (e.g. toxins, lectins, viruses or bacteria) that bind to glycolipids to induce their own uptake into mammalian cells by creating negative membrane curvature and membrane invaginations is explored. We highlight recent trends in understanding nanoscale plasma membrane (re-)organization and present the benefits of using synthetic membrane systems. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
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Affiliation(s)
- Sahaja Aigal
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, Schänzlestraβe 18, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology (IMPRS-MCB), Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany.
| | - Julie Claudinon
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, Schänzlestraβe 18, 79104 Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, Schänzlestraβe 18, 79104 Freiburg, Germany.
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11
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Noskov AN. [Molecular mechanism of AB5 toxin A-subunit translocation into the target cells]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2013; 39:671-9. [PMID: 25696929 DOI: 10.1134/s1068162013050129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AB5 toxins are pore-forming protein complexes, which destroy eukaryotic target cells inactivating essential enzyme complexes through protein ADP-ribosylation or glycosylation by enzymatically active A1 subunits. The B-subunit pentamer interacts with the target cell receptor, induces membrane pore formation, and initiates receptor-mediated endocytosis. In the present article, we propose a model of A1-subunit translocation in the form of a globular structure, as opposed to the generally accepted hypothesis of A-subunit unfolding in the acidic milieu of the endosome followed by its transport in the form of unfolded polypeptide and refolding in the cytoplasm. This model is based on physical-chemical processes and explains why an endosome, but not an exosome, is formed. A-subunit translocation into the cytosol is driven by the proton potential difference generated by K/Na- and H(+)-ATPases. After reduction of the disulphide bond between A1 and A2 fragments by intracellular enzymes, B-subunit returns back into the endosome, where they are destroyed by endosomal proteases, and the pore is closed. Endosome integrates into the cellular membrane, and membrane-bound enzymatic complexes (ATPases and others) return back to their initial position. The proposed model of receptor-mediated endocytosis is a universal molecular mechanism of translocation of effector toxin molecule subunits or any other proteins into the target cell, as well as of cell membrane reparation after any cell membrane injury by pore-forming complexes.
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Establishment of an in vitro transport assay that reveals mechanistic differences in cytosolic events controlling cholera toxin and T-cell receptor α retro-translocation. PLoS One 2013; 8:e75801. [PMID: 24146777 PMCID: PMC3795749 DOI: 10.1371/journal.pone.0075801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/21/2013] [Indexed: 11/19/2022] Open
Abstract
Following retrograde trafficking to the endoplasmic reticulum (ER), cholera toxin A1 (CTA1) subunit hijacks ER-associated degradation (ERAD) machinery and retro-translocates into the cytosol to induce toxicity. We previously established a cell-based in vivo assay to identify ER components that regulate this process. However, elucidating cytosolic events that govern CTA1 retro-translocation using this assay is difficult as manipulating cytosolic factors often perturbs toxin retrograde transport to the ER. To circumvent this problem, we developed an in vitro assay in semi-permeabilized cells that directly monitors CTA1 release from the ER into the cytosol. We demonstrate CTA1 is released into the cytosol as a folded molecule in a p97- and proteasome-independent manner. Release nonetheless involves a GTP-dependent reaction. Upon extending this assay to the canonical ERAD substrate T-cell receptor α (TCRα), we found the receptor is unfolded when released into the cytosol and degraded by membrane-associated proteasome. In this reaction, p97 initially extracts TCRα from the ER membrane, followed by TCRα discharge into the cytosol that requires additional energy-dependent cytosolic activities. Our results reveal mechanistic insights into cytosolic events controlling CTA1 and TCRα retro-translocation, and provide a reliable tool to further probe this process.
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Chinnapen DJF, Hsieh WT, te Welscher YM, Saslowsky DE, Kaoutzani L, Brandsma E, D'Auria L, Park H, Wagner JS, Drake KR, Kang M, Benjamin T, Ullman MD, Costello CE, Kenworthy AK, Baumgart T, Massol RH, Lencer WI. Lipid sorting by ceramide structure from plasma membrane to ER for the cholera toxin receptor ganglioside GM1. Dev Cell 2013; 23:573-86. [PMID: 22975326 DOI: 10.1016/j.devcel.2012.08.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 04/06/2012] [Accepted: 08/04/2012] [Indexed: 01/26/2023]
Abstract
The glycosphingolipid GM1 binds cholera toxin (CT) on host cells and carries it retrograde from the plasma membrane (PM) through endosomes, the trans-Golgi (TGN), and the endoplasmic reticulum (ER) to induce toxicity. To elucidate how a membrane lipid can specify trafficking in these pathways, we synthesized GM1 isoforms with alternate ceramide domains and imaged their trafficking in live cells. Only GM1 with unsaturated acyl chains sorted efficiently from PM to TGN and ER. Toxin binding, which effectively crosslinks GM1 lipids, was dispensable, but membrane cholesterol and the lipid raft-associated proteins actin and flotillin were required. The results implicate a protein-dependent mechanism of lipid sorting by ceramide structure and provide a molecular explanation for the diversity and specificity of retrograde trafficking by CT in host cells.
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Affiliation(s)
- Daniel J-F Chinnapen
- Division of Gastroenterology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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14
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Mechanisms underlying the confined diffusion of cholera toxin B-subunit in intact cell membranes. PLoS One 2012; 7:e34923. [PMID: 22511973 PMCID: PMC3325267 DOI: 10.1371/journal.pone.0034923] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 03/10/2012] [Indexed: 11/19/2022] Open
Abstract
Multivalent glycolipid binding toxins such as cholera toxin have the capacity to cluster glycolipids, a process thought to be important for their functional uptake into cells. In contrast to the highly dynamic properties of lipid probes and many lipid-anchored proteins, the B-subunit of cholera toxin (CTxB) diffuses extremely slowly when bound to its glycolipid receptor GM(1) in the plasma membrane of living cells. In the current study, we used confocal FRAP to examine the origins of this slow diffusion of the CTxB/GM(1) complex at the cell surface, relative to the behavior of a representative GPI-anchored protein, transmembrane protein, and fluorescent lipid analog. We show that the diffusion of CTxB is impeded by actin- and ATP-dependent processes, but is unaffected by caveolae. At physiological temperature, the diffusion of several cell surface markers is unchanged in the presence of CTxB, suggesting that binding of CTxB to membranes does not alter the organization of the plasma membrane in a way that influences the diffusion of other molecules. Furthermore, diffusion of the B-subunit of another glycolipid-binding toxin, Shiga toxin, is significantly faster than that of CTxB, indicating that the confined diffusion of CTxB is not a simple function of its ability to cluster glycolipids. By identifying underlying mechanisms that control CTxB dynamics at the cell surface, these findings help to delineate the fundamental properties of toxin-receptor complexes in intact cell membranes.
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15
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Saito M, Mylvaganum M, Tam P, Novak A, Binnington B, Lingwood C. Structure-dependent pseudoreceptor intracellular traffic of adamantyl globotriaosyl ceramide mimics. J Biol Chem 2012; 287:16073-87. [PMID: 22418442 DOI: 10.1074/jbc.m111.318196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The verotoxin (VT) (Shiga toxin) receptor globotriaosyl ceramide (Gb(3)), mediates VT1/VT2 retrograde transport to the endoplasmic reticulum (ER) for cytosolic A subunit access to inhibit protein synthesis. Adamantyl Gb(3) is an amphipathic competitive inhibitor of VT1/VT2 Gb(3) binding. However, Gb(3)-negative VT-resistant CHO/Jurkat cells incorporate adaGb(3) to become VT1/VT2-sensitive. CarboxyadaGb(3), urea-adaGb(3), and hydroxyethyl adaGb(3), preferentially bound by VT2, also mediate VT1/VT2 cytotoxicity. VT1/VT2 internalize to early endosomes but not to Golgi/ER. AdabisGb(3) (two deacyl Gb(3)s linked to adamantane) protects against VT1/VT2 more effectively than adaGb(3) without incorporating into Gb(3)-negative cells. AdaGb(3) (but not hydroxyethyl adaGb(3)) incorporation into Gb(3)-positive Vero cells rendered punctate cell surface VT1/VT2 binding uniform and subverted subsequent Gb(3)-dependent retrograde transport to Golgi/ER to render cytotoxicity (reduced for VT1 but not VT2) brefeldin A-resistant. VT2-induced vacuolation was maintained in adaGb(3)-treated Vero cells, but vacuolar membrane VT2 was lost. AdaGb(3) destabilized membrane cholesterol and reduced Gb(3) cholesterol stabilization in phospholipid liposomes. Cholera toxin GM1-mediated Golgi/ER targeting was unaffected by adaGb(3). We demonstrate the novel, lipid-dependent, pseudoreceptor function of Gb(3) mimics and their structure-dependent modulation of endogenous intracellular Gb(3) vesicular traffic.
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Affiliation(s)
- Mitsumasa Saito
- Research Institute, Program in Molecular Structure and Function, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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16
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Abstract
All bacterial toxins, which globally are hydrophilic proteins, interact first with their target cells by recognizing a surface receptor, which is either a lipid or a lipid derivative, or another compound but in a lipid environment. Intracellular active toxins follow various trafficking pathways, the sorting of which is greatly dependent on the nature of the receptor, notably lipidic receptor or receptor embedded into a distinct environment such as lipid microdomains. Numerous other toxins act locally on cell membrane. Indeed, phospholipase activity is a common mechanism shared by several membrane-damaging toxins. In addition, many toxins active intracellularly or on cell membrane modulate host cell phospholipid pathways. Unusually, a few bacterial toxins require a lipid post-translational modification to be active. Thereby, lipids are obligate partners of bacterial toxins.
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Affiliation(s)
- Blandine Geny
- Unité des Bactéries Anaérobies et Toxines, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris cedex 15, France
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17
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Boberg A, Stålnacke A, Bråve A, Hinkula J, Wahren B, Carlin N. Receptor Binding by Cholera Toxin B-Subunit and Amino Acid Modification Improves Minimal Peptide Immunogenicity. ISRN MOLECULAR BIOLOGY 2012; 2012:170676. [PMID: 27335661 PMCID: PMC4890861 DOI: 10.5402/2012/170676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 05/20/2012] [Indexed: 11/30/2022]
Abstract
We increase our understanding of augmenting a cellular immune response, by using an HIV-1 protease-derived epitope (PR75–84), and variants thereof, coupled to the C-terminal, of the B subunit of cholera toxin (CTB). Fusion proteins were used for immunizations of HLA-A0201 transgenic C57BL/6 mice. We observed different capacities to elicit a cellular immune response by peptides with additions of five to ten amino acids to the PR epitope. There was a positive correlation between the magnitude of the elicited cellular immune response and the capacity of the fusion protein to bind GM-1. This binding capacity is affected by its ability to form natural pentamers of CTB. Our results suggest that functional CTB pentamers containing a foreign amino acid-modified epitope is a novel way to overcome the limited cellular immunogenicity of minimal peptide antigens. This way of using a functional assay as readout for improved cellular immunogenicity might become highly valuable for difficult immunogens such as short peptides (epitopes).
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Affiliation(s)
- Andreas Boberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 171 82 Stockholm, Sweden; Division of Education and Research administration, Mälardalen University, P.O. Box 883, 721 23 Västerås, Sweden
| | | | - Andreas Bråve
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 171 82 Stockholm, Sweden
| | - Jorma Hinkula
- Institution of Clinical and Experimental Medicine, Linköping University, 581 83 Linköping, Sweden
| | - Britta Wahren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 171 82 Stockholm, Sweden
| | - Nils Carlin
- Etvax AB, Gunnar Asplunds Alle 16, 171 63 Solna, Sweden
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18
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Abstract
EHDs [EH (Eps15 homology)-domain-containing proteins] participate in different stages of endocytosis. EHD2 is a plasma-membrane-associated EHD which regulates trafficking from the plasma membrane and recycling. EHD2 has a role in nucleotide-dependent membrane remodelling and its ATP-binding domain is involved in dimerization, which creates a membrane-binding region. Nucleotide binding is important for association of EHD2 with the plasma membrane, since a nucleotide-free mutant (EHD2 T72A) failed to associate. To elucidate the possible function of EHD2 during endocytic trafficking, we attempted to unravel proteins that interact with EHD2, using the yeast two-hybrid system. A novel interaction was found between EHD2 and Nek3 [NIMA (never in mitosis in Aspergillus nidulans)-related kinase 3], a serine/threonine kinase. EHD2 was also found in association with Vav1, a Nek3-regulated GEF (guanine-nucleotide-exchange factor) for Rho GTPases. Since Vav1 regulates Rac1 activity and promotes actin polymerization, the impact of overexpression of EHD2 on Rac1 activity was tested. The results indicated that wt (wild-type) EHD2, but not its P-loop mutants, reduced Rac1 activity. The inhibitory effect of EHD2 overexpression was partially rescued by co-expression of Rac1 as measured using a cholera toxin trafficking assay. The results of the present study strongly indicate that EHD2 regulates trafficking from the plasma membrane by controlling Rac1 activity.
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19
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Toxin mediated diarrhea in the 21 century: the pathophysiology of intestinal ion transport in the course of ETEC, V. cholerae and rotavirus infection. Toxins (Basel) 2010; 2:2132-57. [PMID: 22069677 PMCID: PMC3153279 DOI: 10.3390/toxins2082132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022] Open
Abstract
An estimated 4 billion episodes of diarrhea occur each year. As a result, 2–3 million children and 0.5–1 million adults succumb to the consequences of this major healthcare concern. The majority of these deaths can be attributed to toxin mediated diarrhea by infectious agents, such as E. coli, V. cholerae or Rotavirus. Our understanding of the pathophysiological processes underlying these infectious diseases has notably improved over the last years. This review will focus on the cellular mechanism of action of the most common enterotoxins and the latest specific therapeutic approaches that have been developed to contain their lethal effects.
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20
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Protein toxins from plants and bacteria: Probes for intracellular transport and tools in medicine. FEBS Lett 2010; 584:2626-34. [DOI: 10.1016/j.febslet.2010.04.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 04/07/2010] [Indexed: 01/07/2023]
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21
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Soo JC, Zhang J, He Q, Agarwal S, Li H, Zhang H, Chen P. Surface immobilized cholera toxin B subunit (CTB) facilitates vesicle docking, trafficking and exocytosis. Integr Biol (Camb) 2010; 2:250-7. [DOI: 10.1039/c0ib00006j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Silveira e Souza AMM, Trindade ES, Jamur MC, Oliver C. Gangliosides are important for the preservation of the structure and organization of RBL-2H3 mast cells. J Histochem Cytochem 2009; 58:83-93. [PMID: 19786609 DOI: 10.1369/jhc.2009.954776] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gangliosides are known to be important in many biological processes. However, details concerning the exact function of these glycosphingolipids in cell physiology are poorly understood. In this study, the role of gangliosides present on the surface of rodent mast cells in maintaining cell structure was examined using RBL-2H3 mast cells and two mutant cell lines (E5 and D1) deficient in the gangliosides, GM(1) and the alpha-galactosyl derivatives of the ganglioside GD(1b). The two deficient cell lines were morphologically different from each other as well as from the parental RBL-2H3 cells. Actin filaments in RBL-2H3 and E5 cells were under the plasma membrane following the spindle shape of the cells, whereas in D1 cells, they were concentrated in large membrane ruffles. Microtubules in RBL-2H3 and E5 cells radiated from the centrosome and were organized into long, straight bundles. The bundles in D1 cells were thicker and organized circumferentially under the plasma membrane. The endoplasmic reticulum, the Golgi complex, and the secretory granule matrix were also altered in the mutant cell lines. These results suggest that the mast cell-specific alpha-galactosyl derivatives of ganglioside GD(1b) and GM(1) are important in maintaining normal cell morphology.
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Affiliation(s)
- Adriana Maria Mariano Silveira e Souza
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, Brazil
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23
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Haines FJ, Griffiths CM, Possee RD, Hawes CR, King LA. Involvement of lipid rafts and cellular actin in AcMNPV GP64 distribution and virus budding. Virol Sin 2009. [DOI: 10.1007/s12250-009-3055-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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24
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Deng GM, Tsokos GC. Cholera toxin B accelerates disease progression in lupus-prone mice by promoting lipid raft aggregation. THE JOURNAL OF IMMUNOLOGY 2008; 181:4019-26. [PMID: 18768857 DOI: 10.4049/jimmunol.181.6.4019] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Infectious agents, including bacteria and viruses, are thought to provide triggers for the development or exacerbation of autoimmune diseases such as systemic lupus erythematosus in the genetically predisposed individual. Molecular mimicry and engagement of TLRs have been assigned limited roles that link infection to autoimmunity, but additional mechanisms are suspected to be involved. In this study we show that T cells from lupus-prone mice display aggregated lipid rafts that harbor signaling, costimulatory, inflammatory, adhesion, and TLR molecules. The percentage of T cells with clustered lipid rafts increases with age and peaks before the development of lupus pathology. We show that cholera toxin B, a component of Vibrio cholerae, promotes autoantibody production and glomerulonephritis in lupus-prone mice by enhancing lipid raft aggregation in T cells. In contrast, disruption of lipid raft aggregation results in delay of disease pathology. Our results demonstrate that lipid rafts contribute significantly to the pathogenesis of lupus and provide a novel mechanism whereby aggregated lipid rafts represent a potential link between infection and autoimmunity.
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Affiliation(s)
- Guo-Min Deng
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
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25
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Lalazar G, Ben Ya'acov A, Eliakim-Raz N, Livovsky DM, Pappo O, Preston S, Zolotarov L, Ilan Y. β-Glycosphingolipids-mediated lipid raft alteration is associated with redistribution of NKT cells and increased intrahepatic CD8+ T lymphocyte trapping. J Lipid Res 2008; 49:1884-93. [DOI: 10.1194/jlr.m800113-jlr200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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26
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Wang M, Hajishengallis G. Lipid raft-dependent uptake, signalling and intracellular fate of Porphyromonas gingivalis in mouse macrophages. Cell Microbiol 2008; 10:2029-42. [PMID: 18547335 DOI: 10.1111/j.1462-5822.2008.01185.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lipid rafts are cholesterol-enriched microdomains involved in cellular trafficking and implicated as portals for certain pathogens. We sought to determine whether the oral pathogen Porphyromonas gingivalis enters macrophages via lipid rafts, and if so, to examine the impact of raft entry on its intracellular fate. Using J774A.1 mouse macrophages, we found that P. gingivalis colocalizes with lipid rafts in a cholesterol-dependent way. Depletion of cellular cholesterol using methyl-beta-cyclodextrin resulted in about 50% inhibition of P. gingivalis uptake, although this effect was reversed by cholesterol reconstitution. The intracellular survival of P. gingivalis was dramatically inhibited in cholesterol-depleted cells relative to untreated or cholesterol-reconstituted cells, even when infections were adjusted to allow equilibration of the initial intracellular bacterial load. P. gingivalis thus appeared to exploit raft-mediated uptake for promoting its survival. Consistent with this, lipid raft disruption enhanced the colocalization of internalized P. gingivalis with lysosomes. In contrast, raft disruption did not affect the expression of host receptors interacting with P. gingivalis, although it significantly inhibited signal transduction. In summary, P. gingivalis uses macrophage lipid rafts as signalling and entry platforms, which determine its intracellular fate to the pathogen's own advantage.
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Affiliation(s)
- Min Wang
- Department of Periodontics/Oral Health and Systemic Disease, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
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27
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Torgersen ML, Wälchli S, Grimmer S, Skånland SS, Sandvig K. Protein Kinase Cδ Is Activated by Shiga Toxin and Regulates Its Transport. J Biol Chem 2007; 282:16317-28. [PMID: 17403690 DOI: 10.1074/jbc.m610886200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein kinase C (PKC) isozymes regulate different vesicular trafficking steps in the recycling or degradative pathways. However, a possible role of these kinases in the retrograde pathway from endosomes to the Golgi complex has previously not been investigated. We report here the involvement of a specific PKC isozyme, PKCdelta, in the intracellular transport of the glycolipid-binding Shiga toxin (Stx), which utilizes the retrograde pathway to intoxicate cells. Upon binding to cells, Stx was shown to specifically activate PKCdelta and not PKCalpha. The involvement of PKCdelta and PKCalpha in the retrograde transport of Stx was then monitored biochemically and by immunofluorescence after inhibition or depletion of the isozymes. PKCdelta, but not PKCalpha, was shown to selectively regulate the endosome-to-Golgi transport of StxB. Upon inhibition or knockdown of PKCdelta, StxB molecules colocalized less with giantin and more with EEA1, indicating that the molecules were accumulated in endosomes, unable to reach the Golgi complex. The inhibition of Golgi transport of Stx was reflected by a strong reduction in the toxic effect, demonstrating that transport of Stx to the cytosol is dependent on PKCdelta activity. These results are in agreement with our previous data, which show that Stx is able to stimulate its own transport.
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Affiliation(s)
- Maria L Torgersen
- Institute for Cancer Research, Faculty Division, The Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo, Norway
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Howell GJ, Holloway ZG, Cobbold C, Monaco AP, Ponnambalam S. Cell biology of membrane trafficking in human disease. ACTA ACUST UNITED AC 2007; 252:1-69. [PMID: 16984815 PMCID: PMC7112332 DOI: 10.1016/s0074-7696(06)52005-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Understanding the molecular and cellular mechanisms underlying membrane traffic pathways is crucial to the treatment and cure of human disease. Various human diseases caused by changes in cellular homeostasis arise through a single gene mutation(s) resulting in compromised membrane trafficking. Many pathogenic agents such as viruses, bacteria, or parasites have evolved mechanisms to subvert the host cell response to infection, or have hijacked cellular mechanisms to proliferate and ensure pathogen survival. Understanding the consequence of genetic mutations or pathogenic infection on membrane traffic has also enabled greater understanding of the interactions between organisms and the surrounding environment. This review focuses on human genetic defects and molecular mechanisms that underlie eukaryote exocytosis and endocytosis and current and future prospects for alleviation of a variety of human diseases.
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Affiliation(s)
- Gareth J Howell
- Endothelial Cell Biology Unit, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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Valencia A, Rajadurai A, Carle AB, Kochevar IE. 7-Dehydrocholesterol enhances ultraviolet A-induced oxidative stress in keratinocytes: roles of NADPH oxidase, mitochondria, and lipid rafts. Free Radic Biol Med 2006; 41:1704-18. [PMID: 17145559 PMCID: PMC1880892 DOI: 10.1016/j.freeradbiomed.2006.09.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 08/23/2006] [Accepted: 09/05/2006] [Indexed: 12/20/2022]
Abstract
Long wavelength solar UVA radiation stimulates formation of reactive oxygen species (ROS) and prostaglandin E(2) (PGE(2)), which are involved in skin photosensitivity and tumor promotion. High levels of 7-dehydrocholesterol (7-DHC), the precursor to cholesterol, cause exaggerated photosensitivity to UVA in patients with Smith-Lemli-Opitz syndrome (SLOS). Partially replacing cholesterol with 7-DHC in keratinocytes rapidly (<5 min) increased UVA-induced ROS, intracellular calcium, phospholipase A(2) activity, PGE(2), and NADPH oxidase activity. UVA-induced ROS and PGE(2) production were inhibited in these cells by depleting the Nox1 subunit of NADPH oxidase using siRNA or using a mitochondrial radical quencher, MitoQ. Partial replacement of cholesterol with 7-DHC also disrupted membrane lipid raft domains, although depletion of cholesterol, which also disrupts lipid rafts, did not affect UVA-induced increases in ROS and PGE(2). Phospholipid liposomes containing 7-DHC were more rapidly oxidized by a free radical mechanism than those containing cholesterol. These results indicate that 7-DHC enhances rapid UVA-induced ROS and PGE(2) formation by enhancing free radical-mediated membrane lipid oxidation and suggests that this mechanism might underlie the UVA photosensitivity in SLOS.
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Affiliation(s)
- Antonio Valencia
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Thier-224, 55 Fruit Street, Boston, MA 02114, USA
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Chinnapen DJF, Chinnapen H, Saslowsky D, Lencer WI. Rafting with cholera toxin: endocytosis and trafficking from plasma membrane to ER. FEMS Microbiol Lett 2006; 266:129-37. [PMID: 17156122 PMCID: PMC3511785 DOI: 10.1111/j.1574-6968.2006.00545.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cholera toxin (CT), and members of the AB(5) family of toxins enter host cells and hijack the cell's endogenous pathways to induce toxicity. CT binds to a lipid receptor on the plasma membrane (PM), ganglioside GM1, which has the ability to associate with lipid rafts. The toxin can then enter the cell by various modes of receptor-mediated endocytosis and traffic in a retrograde manner from the PM to the Golgi and the endoplasmic reticulum (ER). Once in the ER, a portion of the toxin is unfolded and retro-translocated to the cytosol so as to induce disease. GM1 is the vehicle that carries CT from PM to ER. Thus, the toxin pathway from PM to ER is a lipid-based sorting pathway, which is potentially meditated by the determinants of the GM1 ganglioside structure itself.
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Affiliation(s)
- Daniel J.-F. Chinnapen
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - David Saslowsky
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Wayne I. Lencer
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- The Harvard Digestive Diseases Center, Boston, MA, USA
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Sánchez J, Holmgren J. Virulence factors, pathogenesis and vaccine protection in cholera and ETEC diarrhea. Curr Opin Immunol 2005; 17:388-98. [PMID: 15963708 DOI: 10.1016/j.coi.2005.06.007] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 06/03/2005] [Indexed: 11/18/2022]
Abstract
Recent work has provided new insights into the pathogenesis of the potentially life-threatening diarrheas caused by Vibrio cholerae and enterotoxigenic Escherichia coli (ETEC): a new mechanism (post-translational degradation), which is involved in the control of cholera toxin expression, has been discovered. Recent evidence also suggests that vibrios upregulate cholera toxin expression in response to intestinal fluid components, and enterotoxin-carrying bacterial outer membrane vesicles might have a function in ETEC pathogenesis. An important role of the environment is supported by the correlation between cholera incidence and elevated sea surface temperature, which supports the notion that the zooplankton is a V. cholerae reservoir. Additionally, environmental lytic cholera phages could influence cholera seasonality by 'terminating' the seasonal epidemic. Finally, the strong herd immunity elicited by an oral cholera vaccine indicates that cholera vaccination could have a significant public health impact.
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Affiliation(s)
- Joaquín Sánchez
- Facultad de Medicina, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, CP62210, Cuernavaca, Morelos, Mexico
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Lencer WI, Saslowsky D. Raft trafficking of AB5 subunit bacterial toxins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:314-21. [PMID: 16153723 DOI: 10.1016/j.bbamcr.2005.07.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 07/15/2005] [Accepted: 07/19/2005] [Indexed: 02/07/2023]
Abstract
Cholera and the related AB(5)-subunit toxins co-opt plasma membrane (PM) glycolipids to move retrograde into the endoplasmic reticulum (ER) of the host cell where a portion of the toxin is retro-translocated to the cytosol to induce disease. Only glycolipids that associate strongly with detergent insoluble membrane microdomains can sort the toxins backwards from PM to ER. The way certain lipids and proteins are clustered in the plane of the membrane to form lipid rafts likely explains how the glycolipids can function as sorting motifs for the toxins.
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Affiliation(s)
- Wayne I Lencer
- GI Cell Biology, Enders 720, Children's Hospital Boston, the Harvard Digestive Diseases Center, and the Department of Pediatrics, Harvard Medical School, 300 Longwood Ave., Boston, MA 02115, USA.
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