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Etxaniz A, González‐Bullón D, Martín C, Alonso MT, Ostolaza H. Irreversibleversusrepairable membrane poration: differences in permeabilization elicited byBordetellaAdenylate Cyclase Toxin and its hemolysin domain in macrophages. FEBS J 2019; 287:1798-1815. [DOI: 10.1111/febs.15106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 09/03/2019] [Accepted: 10/23/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Asier Etxaniz
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) Instituto Biofisika (UPV/EHU CSIC) Bilbao Spain
| | - David González‐Bullón
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) Instituto Biofisika (UPV/EHU CSIC) Bilbao Spain
| | - César Martín
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) Instituto Biofisika (UPV/EHU CSIC) Bilbao Spain
| | | | - Helena Ostolaza
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) Instituto Biofisika (UPV/EHU CSIC) Bilbao Spain
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Nygren P, Balashova N, Brown AC, Kieba I, Dhingra A, Boesze-Battaglia K, Lally ET. Aggregatibacter actinomycetemcomitans leukotoxin causes activation of lymphocyte function-associated antigen 1. Cell Microbiol 2018; 21:e12967. [PMID: 30329215 DOI: 10.1111/cmi.12967] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/20/2018] [Accepted: 10/05/2018] [Indexed: 11/29/2022]
Abstract
Repeats-in-toxin leukotoxin (LtxA) produced by the oral bacterium Aggregatibacter actinomycetemcomitans kills human leukocytes in a lymphocyte function-associated antigen 1 (LFA-1, integrin αL /β2 )-dependent manner, although the mechanism for this interaction has not been identified. The LtxA internalisation by LFA-1-expressing cells was explored with florescence resonance energy transfer (FRET) microscopy using a cell line that expresses LFA-1 with a cyan fluorescent protein-tagged cytosolic αL domain and a yellow fluorescent protein-tagged β2 domain. Phorbol 12-myristate 13-acetate activation of LFA-1 caused transient cytosolic domain separation. However, addition of LtxA resulted in an increase in FRET, indicating that LtxA brings the cytosolic domains closer together, compared with the inactive state. Unlike activation, this effect was not transient, lasting more than 30 min. Equilibrium constants of LtxA binding to the cytoplasmic domains of both αL and β2 were determined using surface plasmon resonance. LtxA has a strong affinity for the cytosolic domains of both the αL and β2 subunits (Kd = 15 and 4.2 nM, respectively) and a significantly lower affinity for the cytoplasmic domains of other integrin αM , αX , and β3 subunits (Kd = 400, 180, and 230 nM, respectively), used as controls. Peptide fragments of αL and β2 show that LtxA binds membrane-proximal domain of αL and intermediate domain of β2 .
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Affiliation(s)
- Patrik Nygren
- Departments of Biochemistry, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nataliya Balashova
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Angela C Brown
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Irene Kieba
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Anuradha Dhingra
- Departments of Biochemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Edward T Lally
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
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Chenal A, Ladant D. Bioengineering of Bordetella pertussis Adenylate Cyclase Toxin for Antigen-Delivery and Immunotherapy. Toxins (Basel) 2018; 10:E302. [PMID: 30037010 PMCID: PMC6070788 DOI: 10.3390/toxins10070302] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 11/16/2022] Open
Abstract
The adenylate cyclase toxin (CyaA) is one of the major virulence factors of Bordetella pertussis, the causative agent of whooping cough. CyaA is able to invade eukaryotic cells where, upon activation by endogenous calmodulin, it synthesizes massive amounts of cAMP that alters cellular physiology. The CyaA toxin is a 1706 residues-long bifunctional protein: the catalytic domain is located in the 400 amino-proximal residues, whereas the carboxy-terminal 1306 residues are implicated in toxin binding to the cellular receptor, the αMβ₂ (CD11b/CD18) integrin, and subsequently in the translocation of the catalytic domain across the cytoplasmic membrane of the target cells. Indeed, this protein is endowed with the unique capability of delivering its N-terminal catalytic domain directly across the plasma membrane of eukaryotic target cells. These properties have been exploited to engineer the CyaA toxin as a potent non-replicating vector able to deliver antigens into antigen presenting cells and elicit specific cell-mediated immune responses. Antigens of interest can be inserted into the CyaA protein to yield recombinant molecules that are targeted in vivo to dendritic cells, where the antigens are processed and presented by the major class I and class II histocompatibility complexes (MHC-I and II). CyaA turned out to be a remarkably effective and versatile vaccine vector capable of inducing all the components of the immune response (T-CD4, T-CD8, and antibody). In this chapter, we summarize the basic knowledge on the adenylate cyclase toxin and then describe the application of CyaA in vaccinology, including some recent results of clinical trials of immunotherapy using a recombinant CyaA vaccine.
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Affiliation(s)
- Alexandre Chenal
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
| | - Daniel Ladant
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
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do Vale A, Cabanes D, Sousa S. Bacterial Toxins as Pathogen Weapons Against Phagocytes. Front Microbiol 2016; 7:42. [PMID: 26870008 PMCID: PMC4734073 DOI: 10.3389/fmicb.2016.00042] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/11/2016] [Indexed: 12/31/2022] Open
Abstract
Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favor microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signaling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.
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Affiliation(s)
- Ana do Vale
- Host Interaction and Response, Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Group of Fish Immunology and Vaccinology, Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal
| | - Didier Cabanes
- Host Interaction and Response, Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal
| | - Sandra Sousa
- Host Interaction and Response, Instituto de Investigação e Inovação em Saúde, Universidade do PortoPorto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Universidade do PortoPorto, Portugal
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Martín C, Etxaniz A, Uribe KB, Etxebarria A, González-Bullón D, Arlucea J, Goñi FM, Aréchaga J, Ostolaza H. Adenylate Cyclase Toxin promotes bacterial internalisation into non phagocytic cells. Sci Rep 2015; 5:13774. [PMID: 26346097 PMCID: PMC4642564 DOI: 10.1038/srep13774] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 08/04/2015] [Indexed: 02/07/2023] Open
Abstract
Bordetella pertussis causes whooping cough, a respiratory infectious disease that is the fifth largest cause of vaccine-preventable death in infants. Though historically considered an extracellular pathogen, this bacterium has been detected both in vitro and in vivo inside phagocytic and non-phagocytic cells. However the precise mechanism used by B. pertussis for cell entry, or the putative bacterial factors involved, are not fully elucidated. Here we find that adenylate cyclase toxin (ACT), one of the important toxins of B. pertussis, is sufficient to promote bacterial internalisation into non-phagocytic cells. After characterization of the entry route we show that uptake of "toxin-coated bacteria" proceeds via a clathrin-independent, caveolae-dependent entry pathway, allowing the internalised bacteria to survive within the cells. Intracellular bacteria were found inside non-acidic endosomes with high sphingomyelin and cholesterol content, or "free" in the cytosol of the invaded cells, suggesting that the ACT-induced bacterial uptake may not proceed through formation of late endolysosomes. Activation of Tyr kinases and toxin-induced Ca(2+)-influx are essential for the entry process. We hypothesize that B. pertussis might use ACT to activate the endocytic machinery of non-phagocytic cells and gain entry into these cells, in this way evading the host immune system.
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Affiliation(s)
- César Martín
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - Asier Etxaniz
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B. Uribe
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - Aitor Etxebarria
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - David González-Bullón
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - Jon Arlucea
- Departamento de Biología Celular, Facultad de Medicina, Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain
| | - Félix M. Goñi
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
| | - Juan Aréchaga
- Departamento de Biología Celular, Facultad de Medicina, Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain
| | - Helena Ostolaza
- Departamento de Bioquímica y Biología Molecular and Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
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Monoclonal antibodies against Vibrio vulnificus RtxA1 elicit protective immunity through distinct mechanisms. Infect Immun 2014; 82:4813-23. [PMID: 25156730 DOI: 10.1128/iai.02130-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Vibrio vulnificus causes rapidly progressing septicemia with an extremely high mortality rate (≥50%), even with aggressive antibiotic treatment. The bacteria secrete multifunctional autoprocessing repeats-in-toxin (MARTX) toxins, which are involved in the pathogenesis of Gram-negative Vibrio species. Recently, we reported that immunization with the C-terminal region of V. vulnificus RtxA1/MARTXVv, RtxA1-C, elicits a protective immune response against V. vulnificus through a poorly defined mechanism. In this study, we generated a panel of new monoclonal antibodies (MAbs) against V. vulnificus RtxA1-C and investigated their protective efficacies and mechanisms in a mouse model of infection. Prophylactic administration of seven MAbs strongly protected mice against lethal V. vulnificus infection (more than 90% survival). Moreover, three of these MAbs (21RA, 24RA, and 47RA) demonstrated marked efficacy as postexposure therapy. Notably, 21RA was therapeutically effective against lethal V. vulnificus infection by a variety of routes. Using Fab fragments and a neutropenic mouse model, we showed that 21RA and 24RA mediate protection from V. vulnificus infection through an Fc-independent and/or neutrophil-independent pathway. In contrast, 47RA-mediated protection was dependent on its Fc region and was reduced to 50% in neutropenic mice compared with 21RA-mediated and 24RA-mediated protection. Bacteriological study indicated that 21RA appears to enhance the clearance of V. vulnificus from the blood. Overall, these studies suggest that humoral immunity controls V. vulnificus infection through at least two different mechanisms. Furthermore, our panel of MAbs could provide attractive candidates for the further development of immunoprophylaxis/therapeutics and other therapies against V. vulnificus that target the MARTX toxin.
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Bordetella pertussis adenylate cyclase toxin translocation across a tethered lipid bilayer. Proc Natl Acad Sci U S A 2013; 110:20473-8. [PMID: 24297899 DOI: 10.1073/pnas.1312975110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Numerous bacterial toxins can cross biological membranes to reach the cytosol of mammalian cells, where they exert their cytotoxic effects. Our model toxin, the adenylate cyclase (CyaA) from Bordetella pertussis, is able to invade eukaryotic cells by translocating its catalytic domain directly across the plasma membrane of target cells. To characterize its original translocation process, we designed an in vitro assay based on a biomimetic membrane model in which a tethered lipid bilayer (tBLM) is assembled on an amine-gold surface derivatized with calmodulin (CaM). The assembled bilayer forms a continuous and protein-impermeable boundary completely separating the underlying calmodulin (trans side) from the medium above (cis side). The binding of CyaA to the tBLM is monitored by surface plasmon resonance (SPR) spectroscopy. CyaA binding to the immobilized CaM, revealed by enzymatic activity, serves as a highly sensitive reporter of toxin translocation across the bilayer. Translocation of the CyaA catalytic domain was found to be strictly dependent on the presence of calcium and also on the application of a negative potential, as shown earlier in eukaryotic cells. Thus, CyaA is able to deliver its catalytic domain across a biological membrane without the need for any eukaryotic components besides CaM. This suggests that the calcium-dependent CyaA translocation may be driven in part by the electrical field across the membrane. This study's in vitro demonstration of toxin translocation across a tBLM provides an opportunity to explore the molecular mechanisms of protein translocation across biological membranes in precisely defined experimental conditions.
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Uribe KB, Martín C, Etxebarria A, González-Bullón D, Gómez-Bilbao G, Ostolaza H. Ca2+ influx and tyrosine kinases trigger Bordetella adenylate cyclase toxin (ACT) endocytosis. Cell physiology and expression of the CD11b/CD18 integrin major determinants of the entry route. PLoS One 2013; 8:e74248. [PMID: 24058533 PMCID: PMC3772820 DOI: 10.1371/journal.pone.0074248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/31/2013] [Indexed: 12/12/2022] Open
Abstract
Humans infected with Bordetella pertussis, the whooping cough bacterium, show evidences of impaired host defenses. This pathogenic bacterium produces a unique adenylate cyclase toxin (ACT) which enters human phagocytes and catalyzes the unregulated formation of cAMP, hampering important bactericidal functions of these immune cells that eventually cause cell death by apoptosis and/or necrosis. Additionally, ACT permeabilizes cells through pore formation in the target cell membrane. Recently, we demonstrated that ACT is internalised into macrophages together with other membrane components, such as the integrin CD11b/CD18 (CR3), its receptor in these immune cells, and GM1. The goal of this study was to determine whether ACT uptake is restricted to receptor-bearing macrophages or on the contrary may also take place into cells devoid of receptor and gain more insights on the signalling involved. Here, we show that ACT is rapidly eliminated from the cell membrane of either CR3-positive as negative cells, though through different entry routes, which depends in part, on the target cell physiology and characteristics. ACT-induced Ca(2+) influx and activation of non-receptor Tyr kinases into the target cell appear to be common master denominators in the different endocytic strategies activated by this toxin. Very importantly, we show that, upon incubation with ACT, target cells are capable of repairing the cell membrane, which suggests the mounting of an anti-toxin cell repair-response, very likely involving the toxin elimination from the cell surface.
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Affiliation(s)
- Kepa B. Uribe
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
| | - César Martín
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
| | - Aitor Etxebarria
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
| | - David González-Bullón
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
| | - Geraxane Gómez-Bilbao
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
| | - Helena Ostolaza
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, UPV/EHU, Bilbao, Spain
- * E-mail:
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Fiser R, Masin J, Bumba L, Pospisilova E, Fayolle C, Basler M, Sadilkova L, Adkins I, Kamanova J, Cerny J, Konopasek I, Osicka R, Leclerc C, Sebo P. Calcium influx rescues adenylate cyclase-hemolysin from rapid cell membrane removal and enables phagocyte permeabilization by toxin pores. PLoS Pathog 2012; 8:e1002580. [PMID: 22496638 PMCID: PMC3320606 DOI: 10.1371/journal.ppat.1002580] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 01/26/2012] [Indexed: 01/29/2023] Open
Abstract
Bordetella adenylate cyclase toxin-hemolysin (CyaA) penetrates the cytoplasmic membrane of phagocytes and employs two distinct conformers to exert its multiple activities. One conformer forms cation-selective pores that permeabilize phagocyte membrane for efflux of cytosolic potassium. The other conformer conducts extracellular calcium ions across cytoplasmic membrane of cells, relocates into lipid rafts, translocates the adenylate cyclase enzyme (AC) domain into cells and converts cytosolic ATP to cAMP. We show that the calcium-conducting activity of CyaA controls the path and kinetics of endocytic removal of toxin pores from phagocyte membrane. The enzymatically inactive but calcium-conducting CyaA-AC− toxoid was endocytosed via a clathrin-dependent pathway. In contrast, a doubly mutated (E570K+E581P) toxoid, unable to conduct Ca2+ into cells, was rapidly internalized by membrane macropinocytosis, unless rescued by Ca2+ influx promoted in trans by ionomycin or intact toxoid. Moreover, a fully pore-forming CyaA-ΔAC hemolysin failed to permeabilize phagocytes, unless endocytic removal of its pores from cell membrane was decelerated through Ca2+ influx promoted by molecules locked in a Ca2+-conducting conformation by the 3D1 antibody. Inhibition of endocytosis also enabled the native B. pertussis-produced CyaA to induce lysis of J774A.1 macrophages at concentrations starting from 100 ng/ml. Hence, by mediating calcium influx into cells, the translocating conformer of CyaA controls the removal of bystander toxin pores from phagocyte membrane. This triggers a positive feedback loop of exacerbated cell permeabilization, where the efflux of cellular potassium yields further decreased toxin pore removal from cell membrane and this further enhances cell permeabilization and potassium efflux. The adenylate cyclase toxin (CyaA) of pathogenic Bordetellae eliminates the first line of host innate immune defense by inhibiting the oxidative burst and complement-mediated opsonophagocytic killing of bacteria. The toxin penetrates myeloid phagocytes, such as neutrophil, macrophage or dendritic cells, and subverts their signaling by catalyzing a rapid and massive conversion of intracellular ATP to the key signaling molecule cAMP. In parallel, the toxin forms cation-selective pores and permeabilizes the cytoplasmic membrane of phagocytes. This so-called ‘hemolysin’ activity synergizes with the enzymatic AC activity of CyaA in promoting apoptotic or necrotic cell death, depending on the toxin dose. Moreover, the pore-forming activity promotes activation of NALP3 inflammasome and release of interleukin IL-1β. We show here that the capacity of CyaA to permeabilize phagocytes depends on its ability to mediate influx of extracellular calcium ions into cells. This enables bystander CyaA pores to escape rapid macropinocytic removal from cell membrane and exacerbate the permeabilization of cells. These observations set a new paradigm for the mechanism of action of pore-forming RTX leukotoxins on phagocytes.
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Affiliation(s)
- Radovan Fiser
- Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Eva Pospisilova
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | | | - Marek Basler
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Lenka Sadilkova
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Irena Adkins
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Jana Kamanova
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Jan Cerny
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Ivo Konopasek
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
| | - Claude Leclerc
- Institut Pasteur, Paris, France
- INSERM U1041, Paris, France
| | - Peter Sebo
- Institute of Microbiology of the ASCR, v.v.i., Prague, Czech Republic
- Institute of Biotechnology of the ASCR, v.v.i., Prague, Czech Republic
- * E-mail:
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Karst JC, Barker R, Devi U, Swann MJ, Davi M, Roser SJ, Ladant D, Chenal A. Identification of a region that assists membrane insertion and translocation of the catalytic domain of Bordetella pertussis CyaA toxin. J Biol Chem 2012; 287:9200-12. [PMID: 22241477 DOI: 10.1074/jbc.m111.316166] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The adenylate cyclase (CyaA) toxin, one of the virulence factors secreted by Bordetella pertussis, the pathogenic bacteria responsible for whooping cough, plays a critical role in the early stages of respiratory tract colonization by this bacterium. The CyaA toxin is able to invade eukaryotic cells by translocating its N-terminal catalytic domain directly across the plasma membrane of the target cells, where, activated by endogenous calmodulin, it produces supraphysiological levels of cAMP. How the catalytic domain is transferred from the hydrophilic extracellular medium into the hydrophobic environment of the membrane and then to the cell cytoplasm remains an unsolved question. In this report, we have characterized the membrane-interacting properties of the CyaA catalytic domain. We showed that a protein covering the catalytic domain (AC384, encompassing residues 1-384 of CyaA) displayed no membrane association propensity. However, a longer polypeptide (AC489), encompassing residues 1-489 of CyaA, exhibited the intrinsic property to bind to membranes and to induce lipid bilayer destabilization. We further showed that deletion of residues 375-485 within CyaA totally abrogated the toxin's ability to increase intracellular cAMP in target cells. These results indicate that, whereas the calmodulin dependent enzymatic domain is restricted to the amino-terminal residues 1-384 of CyaA, the membrane-interacting, translocation-competent domain extends up to residue 489. This thus suggests an important role of the region adjacent to the catalytic domain of CyaA in promoting its interaction with and its translocation across the plasma membrane of target cells.
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Affiliation(s)
- Johanna C Karst
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Paris, France
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Role of CD11b/CD18 in the process of intoxication by the adenylate cyclase toxin of Bordetella pertussis. Infect Immun 2011; 80:850-9. [PMID: 22144488 DOI: 10.1128/iai.05979-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The adenylate cyclase toxin (ACT) of Bordetella pertussis does not require a receptor to generate intracellular cyclic AMP (cAMP) in a broad range of cell types. To intoxicate cells, ACT binds to the cell surface, translocates its catalytic domain across the cell membrane, and converts intracellular ATP to cAMP. In cells that express the integrin CD11b/CD18 (CR3), ACT is more potent than in CR3-negative cells. We find, however, that the maximum levels of cAMP accumulation inside CR3-positive and -negative cells are comparable. To better understand how CR3 affects the generation of cAMP, we used Chinese hamster ovary and K562 cells transfected to express CR3 and examined the steps in intoxication in the presence and absence of the integrin. The binding of ACT to cells is greater in CR3-expressing cells at all concentrations of ACT, and translocation of the catalytic domain is enhanced by CR3 expression, with ∼80% of ACT molecules translocating their catalytic domain in CR3-positive cells but only 25% in CR3-negative cells. Once in the cytosol, the unregulated catalytic domain converts ATP to cAMP, and at ACT concentrations >1,000 ng/ml, the intracellular ATP concentration is <5% of that in untreated cells, regardless of CR3 expression. This depletion of ATP prevents further production of cAMP, despite the CR3-mediated enhancement of binding and translocation. In addition to characterizing the effects of CR3 on the actions of ACT, these data show that ATP consumption is yet another concentration-dependent activity of ACT that must be considered when studying how ACT affects target cells.
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