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Lepesheva A, Grobarcikova M, Osickova A, Jurnecka D, Knoblochova S, Cizkova M, Osicka R, Sebo P, Masin J. Modification of the RTX domain cap by acyl chains of adapted length rules the formation of functional hemolysin pores. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184311. [PMID: 38570122 DOI: 10.1016/j.bbamem.2024.184311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/14/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
The acylated pore-forming Repeats in ToXin (RTX) cytolysins α-hemolysin (HlyA) and adenylate cyclase toxin (CyaA) preferentially bind to β2 integrins of myeloid leukocytes but can also promiscuously bind and permeabilize cells lacking the β2 integrins. We constructed a HlyA1-563/CyaA860-1706 chimera that was acylated either by the toxin-activating acyltransferase CyaC, using sixteen carbon-long (C16) acyls, or by the HlyC acyltransferase using fourteen carbon-long (C14) acyls. Cytolysin assays with the C16- or C14-acylated HlyA/CyaA chimeric toxin revealed that the RTX domain of CyaA can functionally replace the RTX domain of HlyA only if it is modified by C16-acyls on the Lys983 residue of CyaA. The C16-monoacylated HlyA/CyaA chimera was as pore-forming and cytolytic as native HlyA, whereas the C14-acylated chimera exhibited very low pore-forming activity. Hence, the capacity of the RTX domain of CyaA to support the insertion of the N-terminal pore-forming domain into the target cell membrane, and promote formation of toxin pores, strictly depends on the modification of the Lys983 residue by an acyl chain of adapted length.
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Affiliation(s)
- Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Michaela Grobarcikova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Cizkova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Four Cholesterol-Recognition Motifs in the Pore-Forming and Translocation Domains of Adenylate Cyclase Toxin Are Essential for Invasion of Eukaryotic Cells and Lysis of Erythrocytes. Int J Mol Sci 2022; 23:ijms23158703. [PMID: 35955837 PMCID: PMC9369406 DOI: 10.3390/ijms23158703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/21/2022] [Accepted: 08/02/2022] [Indexed: 12/05/2022] Open
Abstract
Adenylate Cyclase Toxin (ACT or CyaA) is one of the important virulence factors secreted by Bordetella pertussis, the bacterium causative of whooping cough. ACT debilitates host defenses by production of unregulated levels of cAMP into the cell cytosol upon delivery of its N-terminal domain with adenylate cyclase activity (AC domain) and by forming pores in the plasma membrane of macrophages. Binding of soluble toxin monomers to the plasma membrane of target cells and conversion into membrane-integrated proteins are the first and last step for these toxin activities; however, the molecular determinants in the protein or the target membrane that govern this conversion to an active toxin form are fully unknown. It was previously reported that cytotoxic and cytolytic activities of ACT depend on membrane cholesterol. Here we show that ACT specifically interacts with membrane cholesterol, and find in two membrane-interacting ACT domains, four cholesterol-binding motifs that are essential for AC domain translocation and lytic activities. We hypothesize that direct ACT interaction with membrane cholesterol through those four cholesterol-binding motifs drives insertion and stabilizes the transmembrane topology of several helical elements that ultimately build the ACT structure for AC delivery and pore-formation, thereby explaining the cholesterol-dependence of the ACT activities. The requirement for lipid-mediated stabilization of transmembrane helices appears to be a unifying mechanism to modulate toxicity in pore-forming toxins.
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient 'contact weapons' that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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Affiliation(s)
| | | | | | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (K.F.); (W.U.R.); (A.O.)
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Lepesheva A, Osickova A, Holubova J, Jurnecka D, Knoblochova S, Espinosa-Vinals C, Bumba L, Skopova K, Fiser R, Osicka R, Sebo P, Masin J. Different roles of conserved tyrosine residues of the acylated domains in folding and activity of RTX toxins. Sci Rep 2021; 11:19814. [PMID: 34615931 PMCID: PMC8494930 DOI: 10.1038/s41598-021-99112-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/17/2021] [Indexed: 12/31/2022] Open
Abstract
Pore-forming repeats in toxins (RTX) are key virulence factors of many Gram-negative pathogens. We have recently shown that the aromatic side chain of the conserved tyrosine residue 940 within the acylated segment of the RTX adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) plays a key role in target cell membrane interaction of the toxin. Therefore, we used a truncated CyaA-derived RTX719 construct to analyze the impact of Y940 substitutions on functional folding of the acylated segment of CyaA. Size exclusion chromatography combined with CD spectroscopy revealed that replacement of the aromatic side chain of Y940 by the side chains of alanine or proline residues disrupted the calcium-dependent folding of RTX719 and led to self-aggregation of the otherwise soluble and monomeric protein. Intriguingly, corresponding alanine substitutions of the conserved Y642, Y643 and Y639 residues in the homologous RtxA, HlyA and ApxIA hemolysins from Kingella kingae, Escherichia coli and Actinobacillus pleuropneumoniae, affected the membrane insertion, pore-forming (hemolytic) and cytotoxic capacities of these toxins only marginally. Activities of these toxins were impaired only upon replacement of the conserved tyrosines by proline residues. It appears, hence, that the critical role of the aromatic side chain of the Y940 residue is highly specific for the functional folding of the acylated domain of CyaA and determines its capacity to penetrate target cell membrane.
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Affiliation(s)
- Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | | | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Karolina Skopova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Espinosa-Vinals CA, Masin J, Holubova J, Stanek O, Jurnecka D, Osicka R, Sebo P, Bumba L. Almost half of the RTX domain is dispensable for complement receptor 3 binding and cell-invasive activity of the Bordetella adenylate cyclase toxin. J Biol Chem 2021; 297:100833. [PMID: 34051233 PMCID: PMC8214218 DOI: 10.1016/j.jbc.2021.100833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 01/20/2023] Open
Abstract
The whooping cough agent Bordetella pertussis secretes an adenylate cyclase toxin (CyaA) that through its large carboxy-proximal Repeat-in-ToXin (RTX) domain binds the complement receptor 3 (CR3). The RTX domain consists of five blocks (I-V) of characteristic glycine and aspartate-rich nonapeptides that fold into five Ca2+-loaded parallel β-rolls. Previous work indicated that the CR3-binding structure comprises the interface of β-rolls II and III. To test if further portions of the RTX domain contribute to CR3 binding, we generated a construct with the RTX block II/III interface (CyaA residues 1132-1294) linked directly to the C-terminal block V fragment bearing the folding scaffold (CyaA residues 1562-1681). Despite deletion of 267 internal residues of the RTX domain, the Ca2+-driven folding of the hybrid block III/V β-roll still supported formation of the CR3-binding structure at the interface of β-rolls II and III. Moreover, upon stabilization by N- and C-terminal flanking segments, the block III/V hybrid-comprising constructs competed with CyaA for CR3 binding and induced formation of CyaA toxin-neutralizing antibodies in mice. Finally, a truncated CyaAΔ1295-1561 toxin bound and penetrated erythrocytes and CR3-expressing cells, showing that the deleted portions of RTX blocks III, IV, and V (residues 1295-1561) were dispensable for CR3 binding and for toxin translocation across the target cell membrane. This suggests that almost a half of the RTX domain of CyaA is not involved in target cell interaction and rather serves the purpose of toxin secretion.
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Affiliation(s)
- Carlos Angel Espinosa-Vinals
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic; University of Chemistry and Technology, Prague, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ondrej Stanek
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | - Ladislav Bumba
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Masin J, Osickova A, Jurnecka D, Klimova N, Khaliq H, Sebo P, Osicka R. Retargeting from the CR3 to the LFA-1 receptor uncovers the adenylyl cyclase enzyme-translocating segment of Bordetella adenylate cyclase toxin. J Biol Chem 2020; 295:9349-9365. [PMID: 32393579 DOI: 10.1074/jbc.ra120.013630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/07/2020] [Indexed: 12/11/2022] Open
Abstract
The Bordetella adenylate cyclase toxin-hemolysin (CyaA) and the α-hemolysin (HlyA) of Escherichia coli belong to the family of cytolytic pore-forming Repeats in ToXin (RTX) cytotoxins. HlyA preferentially binds the αLβ2 integrin LFA-1 (CD11a/CD18) of leukocytes and can promiscuously bind and also permeabilize many other cells. CyaA bears an N-terminal adenylyl cyclase (AC) domain linked to a pore-forming RTX cytolysin (Hly) moiety, binds the complement receptor 3 (CR3, αMβ2, CD11b/CD18, or Mac-1) of myeloid phagocytes, penetrates their plasma membrane, and delivers the AC enzyme into the cytosol. We constructed a set of CyaA/HlyA chimeras and show that the CyaC-acylated segment and the CR3-binding RTX domain of CyaA can be functionally replaced by the HlyC-acylated segment and the much shorter RTX domain of HlyA. Instead of binding CR3, a CyaA1-710/HlyA411-1024 chimera bound the LFA-1 receptor and effectively delivered AC into Jurkat T cells. At high chimera concentrations (25 nm), the interaction with LFA-1 was not required for CyaA1-710/HlyA411-1024 binding to CHO cells. However, interaction with the LFA-1 receptor strongly enhanced the specific capacity of the bound CyaA1-710/HlyA411-1024 chimera to penetrate cells and deliver the AC enzyme into their cytosol. Hence, interaction of the acylated segment and/or the RTX domain of HlyA with LFA-1 promoted a productive membrane interaction of the chimera. These results help delimit residues 400-710 of CyaA as an "AC translocon" sufficient for translocation of the AC polypeptide across the plasma membrane of target cells.
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Affiliation(s)
- Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nela Klimova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Humaira Khaliq
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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7
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Negative charge of the AC-to-Hly linking segment modulates calcium-dependent membrane activities of Bordetella adenylate cyclase toxin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183310. [PMID: 32333856 DOI: 10.1016/j.bbamem.2020.183310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/31/2020] [Accepted: 04/13/2020] [Indexed: 02/08/2023]
Abstract
Two distinct conformers of the adenylate cyclase toxin (CyaA) appear to accomplish its two parallel activities within target cell membrane. The translocating conformer would deliver the N-terminal adenylyl cyclase (AC) enzyme domain across plasma membrane into cytosol of cells, while the pore precursor conformer would assemble into oligomeric cation-selective pores and permeabilize cellular membrane. Both toxin activities then involve a membrane-interacting 'AC-to-Hly-linking segment' (residues 400 to 500). Here, we report the NMR structure of the corresponding CyaA411-490 polypeptide in dodecylphosphocholine micelles and show that it consists of two α-helices linked by an unrestrained loop. The N-terminal α-helix (Gly418 to His439) remained solvent accessible, while the C-terminal α-helix (His457 to Phe485) was fully enclosed within detergent micelles. CyaA411-490 weakly bound Ca2+ ions (apparent KD 2.6 mM) and permeabilized negatively charged lipid vesicles. At high concentrations (10 μM) the CyaA411-490 polypeptide formed stable conductance units in artificial lipid bilayers with applied voltage, suggesting its possible transmembrane orientation in the membrane-inserted toxin. Mutagenesis revealed that two clusters of negatively charged residues within the 'AC-to-Hly-linking segment' (Glu419 to Glu432 and Asp445 to Glu448) regulate the balance between the AC domain translocating and pore-forming capacities of CyaA in function of calcium concentration.
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Lucas R, Hadizamani Y, Gonzales J, Gorshkov B, Bodmer T, Berthiaume Y, Moehrlen U, Lode H, Huwer H, Hudel M, Mraheil MA, Toque HAF, Chakraborty T, Hamacher J. Impact of Bacterial Toxins in the Lungs. Toxins (Basel) 2020; 12:toxins12040223. [PMID: 32252376 PMCID: PMC7232160 DOI: 10.3390/toxins12040223] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial toxins play a key role in the pathogenesis of lung disease. Based on their structural and functional properties, they employ various strategies to modulate lung barrier function and to impair host defense in order to promote infection. Although in general, these toxins target common cellular signaling pathways and host compartments, toxin- and cell-specific effects have also been reported. Toxins can affect resident pulmonary cells involved in alveolar fluid clearance (AFC) and barrier function through impairing vectorial Na+ transport and through cytoskeletal collapse, as such, destroying cell-cell adhesions. The resulting loss of alveolar-capillary barrier integrity and fluid clearance capacity will induce capillary leak and foster edema formation, which will in turn impair gas exchange and endanger the survival of the host. Toxins modulate or neutralize protective host cell mechanisms of both the innate and adaptive immunity response during chronic infection. In particular, toxins can either recruit or kill central players of the lung's innate immune responses to pathogenic attacks, i.e., alveolar macrophages (AMs) and neutrophils. Pulmonary disorders resulting from these toxin actions include, e.g., acute lung injury (ALI), the acute respiratory syndrome (ARDS), and severe pneumonia. When acute infection converts to persistence, i.e., colonization and chronic infection, lung diseases, such as bronchitis, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) can arise. The aim of this review is to discuss the impact of bacterial toxins in the lungs and the resulting outcomes for pathogenesis, their roles in promoting bacterial dissemination, and bacterial survival in disease progression.
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Affiliation(s)
- Rudolf Lucas
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
| | - Yalda Hadizamani
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
| | - Joyce Gonzales
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Thomas Bodmer
- Labormedizinisches Zentrum Dr. Risch, Waldeggstr. 37 CH-3097 Liebefeld, Switzerland;
| | - Yves Berthiaume
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Ueli Moehrlen
- Pediatric Surgery, University Children’s Hospital, Zürich, Steinwiesstrasse 75, CH-8032 Zürch, Switzerland;
| | - Hartmut Lode
- Insitut für klinische Pharmakologie, Charité, Universitätsklinikum Berlin, Reichsstrasse 2, D-14052 Berlin, Germany;
| | - Hanno Huwer
- Department of Cardiothoracic Surgery, Voelklingen Heart Center, 66333 Voelklingen/Saar, Germany;
| | - Martina Hudel
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Mobarak Abu Mraheil
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Haroldo Alfredo Flores Toque
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Trinad Chakraborty
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Jürg Hamacher
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
- Medical Clinic V-Pneumology, Allergology, Intensive Care Medicine and Environmental Medicine, Faculty of Medicine, Saarland University, University Medical Centre of the Saarland, D-66421 Homburg, Germany
- Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, D-66421 Homburg, Germany
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
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9
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Knapp O, Benz R. Membrane Activity and Channel Formation of the Adenylate Cyclase Toxin (CyaA) of Bordetella pertussis in Lipid Bilayer Membranes. Toxins (Basel) 2020; 12:toxins12030169. [PMID: 32164365 PMCID: PMC7150934 DOI: 10.3390/toxins12030169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/20/2020] [Accepted: 02/22/2020] [Indexed: 12/14/2022] Open
Abstract
The Gram-negative bacterium Bordetella pertussis is the cause of whooping cough. One of its pathogenicity factors is the adenylate cyclase toxin (CyaA) secreted by a Type I export system. The 1706 amino acid long CyaA (177 kDa) belongs to the continuously increasing family of repeat in toxin (RTX) toxins because it contains in its C-terminal half a high number of nine-residue tandem repeats. The protein exhibits cytotoxic and hemolytic activities that target primarily myeloid phagocytic cells expressing the αMβ2 integrin receptor (CD11b/CD18). CyaA represents an exception among RTX cytolysins because the first 400 amino acids from its N-terminal end possess a calmodulin-activated adenylate cyclase (AC) activity. The entry of the AC into target cells is not dependent on the receptor-mediated endocytosis pathway and penetrates directly across the cytoplasmic membrane of a variety of epithelial and immune effector cells. The hemolytic activity of CyaA is rather low, which may have to do with its rather low induced permeability change of target cells and its low conductance in lipid bilayer membranes. CyaA forms highly cation-selective channels in lipid bilayers that show a strong dependence on aqueous pH. The pore-forming activity of CyaA but not its single channel conductance is highly dependent on Ca2+ concentration with a half saturation constant of about 2 to 4 mM.
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Affiliation(s)
- Oliver Knapp
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
- Correspondence: (O.K.); (R.B.)
| | - Roland Benz
- Rudolf-Virchow-Center, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
- Correspondence: (O.K.); (R.B.)
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Benz R, Piselli C, Potter AA. Channel Formation by LktA of Mannheimia (Pasteurella) haemolytica in Lipid Bilayer Membranes and Comparison of Channel Properties with Other RTX-Cytolysins. Toxins (Basel) 2019; 11:toxins11100604. [PMID: 31627319 PMCID: PMC6833087 DOI: 10.3390/toxins11100604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/22/2019] [Accepted: 10/10/2019] [Indexed: 12/17/2022] Open
Abstract
Cytolysin LktA is one of the major pathogenicity factors of Mannheimia haemolytica (formerly Pasteurella haemolytica) that is the cause of pasteurellosis, also known as shipping fever pneumonia, causing substantial loss of sheep and cattle during transport. LktA belongs to the family of RTX-toxins (Repeats in ToXins) that are produced as pathogenicity factors by a variety of Gram-negative bacteria. Sublytic concentrations of LktA cause inflammatory responses of ovine leukocytes. Higher concentrations result in formation of transmembrane channels in target cells that may cause cell lysis and apoptosis. In this study we investigated channel formation by LktA in artificial lipid bilayer membranes made of different lipids. LktA purified from culture supernatants by polyethylene glycol 4000 precipitation and lyophilization had to be activated to frequently form channels by solution in 6 M urea. The LktA channels had a single-channel conductance of about 60 pS in 0.1 M KCl, which is about one tenth of the conductance of most RTX-toxins with the exception of adenylate cyclase toxin of Bordetella pertussis. The LktA channels are highly cation-selective caused by negative net charges. The theoretical treatment of the conductance of LktA as a function of the bulk aqueous concentration allowed a rough estimate of the channel diameter, which is around 1.5 nm. The size of the LktA channel is discussed with respect to channels formed by other RTX-toxins. We present here the first investigation of LktA in a reconstituted system.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs-University Bremen gGmbH Campusring, 1; 28759 Bremen, Germany.
| | - Claudio Piselli
- Department of Life Sciences and Chemistry, Jacobs-University Bremen gGmbH Campusring, 1; 28759 Bremen, Germany.
| | - Andrew A Potter
- Vaccine and Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N5E3, Canada.
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Ostolaza H, González-Bullón D, Uribe KB, Martín C, Amuategi J, Fernandez-Martínez X. Membrane Permeabilization by Pore-Forming RTX Toxins: What Kind of Lesions Do These Toxins Form? Toxins (Basel) 2019; 11:toxins11060354. [PMID: 31216745 PMCID: PMC6628442 DOI: 10.3390/toxins11060354] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/12/2019] [Accepted: 06/16/2019] [Indexed: 12/22/2022] Open
Abstract
Pore-forming toxins (PFTs) form nanoscale pores across target membranes causing cell death. The pore-forming cytolysins of the RTX (repeats in toxin) family belong to a steadily increasing family of proteins characterized by having in their primary sequences a number of glycine- and aspartate-rich nonapeptide repeats. They are secreted by a variety of Gram-negative bacteria and form ion-permeable pores in several cell types, such as immune cells, epithelial cells, or erythrocytes. Pore-formation by RTX-toxins leads to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. The pores formed in lipid bilayers by the RTX-toxins share some common properties such as cation selectivity and voltage-dependence. Hemolytic and cytolytic RTX-toxins are important virulence factors in the pathogenesis of the producing bacteria. And hence, understanding the function of these proteins at the molecular level is critical to elucidating their role in disease processes. In this review we summarize the current state of knowledge on pore-formation by RTX toxins, and include recent results from our own laboratory regarding the pore-forming activity of adenylate cyclase toxin (ACT or CyaA), a large protein toxin secreted by Bordetella pertussis, the bacterium causative of whooping cough.
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Affiliation(s)
- Helena Ostolaza
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - David González-Bullón
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Cesar Martín
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Jone Amuategi
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Xabier Fernandez-Martínez
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
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González-Bullón D, Uribe KB, Largo E, Guembelzu G, García-Arribas AB, Martín C, Ostolaza H. Membrane Permeabilization by Bordetella Adenylate Cyclase Toxin Involves Pores of Tunable Size. Biomolecules 2019; 9:biom9050183. [PMID: 31083482 PMCID: PMC6572617 DOI: 10.3390/biom9050183] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/02/2019] [Accepted: 05/05/2019] [Indexed: 01/27/2023] Open
Abstract
RTX (Repeats in ToXin) pore-forming toxins constitute an expanding family of exoproteins secreted by many Gram-negative bacteria and involved in infectious diseases caused by said pathogens. Despite the relevance in the host/pathogen interactions, the structure and characteristics of the lesions formed by these toxins remain enigmatic. Here, we capture the first direct nanoscale pictures of lytic pores formed by an RTX toxin, the Adenylate cyclase (ACT), secreted by the whooping cough bacterium Bordetella pertussis. We reveal that ACT associates into growing-size oligomers of variable stoichiometry and heterogeneous architecture (lines, arcs, and rings) that pierce the membrane, and that, depending on the incubation time and the toxin concentration, evolve into large enough “holes” so as to allow the flux of large molecular mass solutes, while vesicle integrity is preserved. We also resolve ACT assemblies of similar variable stoichiometry in the cell membrane of permeabilized target macrophages, proving that our model system recapitulates the process of ACT permeabilization in natural membranes. Based on our data we propose a non-concerted monomer insertion and sequential mechanism of toroidal pore formation by ACT. A size-tunable pore adds a new regulatory element to ACT-mediated cytotoxicity, with different pore sizes being putatively involved in different physiological scenarios or cell types.
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Affiliation(s)
- David González-Bullón
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
| | - Eneko Largo
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
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Roderova J, Osickova A, Sukova A, Mikusova G, Fiser R, Sebo P, Osicka R, Masin J. Residues 529 to 549 participate in membrane penetration and pore-forming activity of the Bordetella adenylate cyclase toxin. Sci Rep 2019; 9:5758. [PMID: 30962483 PMCID: PMC6453906 DOI: 10.1038/s41598-019-42200-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 03/27/2019] [Indexed: 11/30/2022] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) of pathogenic Bordetellae delivers its adenylyl cyclase (AC) enzyme domain into the cytosol of host cells and catalyzes uncontrolled conversion of cellular ATP to cAMP. In parallel, the toxin forms small cation-selective pores that permeabilize target cell membrane and account for the hemolytic activity of CyaA on erythrocytes. The pore-forming domain of CyaA is predicted to consist of five transmembrane α-helices, of which the helices I, III, IV and V have previously been characterized. We examined here the α-helix II that is predicted to form between residues 529 to 549. Substitution of the glycine 531 residue by a proline selectively reduced the hemolytic capacity but did not affect the AC translocating activity of the CyaA-G531P toxin. In contrast, CyaA toxins with alanine 538 or 546 replaced by diverse residues were selectively impaired in the capacity to translocate the AC domain across cell membrane but remained fully hemolytic. Such toxins, however, formed pores in planar asolectin bilayer membranes with a very low frequency and with at least two different conducting states. The helix-breaking substitution of alanine 538 by a proline residue abolished the voltage-activated increase of membrane activity of CyaA in asolectin bilayers. These results reveal that the predicted α-helix comprising the residues 529 to 549 plays a key role in CyaA penetration into the target plasma membrane and pore-forming activity of the toxin.
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Affiliation(s)
- Jana Roderova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Anna Sukova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Gabriela Mikusova
- Charles University, Department of Genetics and Microbiology, Faculty of Science, Vinicna 5, 128 43, Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic.,Charles University, Department of Genetics and Microbiology, Faculty of Science, Vinicna 5, 128 43, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic.
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Boehm DT, Hall JM, Wong TY, DiVenere AM, Sen-Kilic E, Bevere JR, Bradford SD, Blackwood CB, Elkins CM, DeRoos KA, Gray MC, Cooper CG, Varney ME, Maynard JA, Hewlett EL, Barbier M, Damron FH. Evaluation of Adenylate Cyclase Toxoid Antigen in Acellular Pertussis Vaccines by Using a Bordetella pertussis Challenge Model in Mice. Infect Immun 2018; 86:e00857-17. [PMID: 30012638 PMCID: PMC6204743 DOI: 10.1128/iai.00857-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 07/10/2018] [Indexed: 12/21/2022] Open
Abstract
Bordetella pertussis is the primary causative agent of pertussis (whooping cough), which is a respiratory infection that leads to a violent cough and can be fatal in infants. There is a need to develop more effective vaccines because of the resurgence of cases of pertussis in the United States since the switch from the whole-cell pertussis vaccines (wP) to the acellular pertussis vaccines (aP; diphtheria-tetanus-acellular-pertussis vaccine/tetanus-diphtheria-pertussis vaccine). Adenylate cyclase toxin (ACT) is a major virulence factor of B. pertussis that is (i) required for establishment of infection, (ii) an effective immunogen, and (iii) a protective antigen. The C-terminal repeats-in-toxin domain (RTX) of ACT is sufficient to induce production of toxin-neutralizing antibodies. In this study, we characterized the effectiveness of vaccines containing the RTX antigen against experimental murine infection with B. pertussis RTX was not protective as a single-antigen vaccine against B. pertussis challenge, and adding RTX to 1/5 human dose of aP did not enhance protection. Since the doses of aP used in murine studies are not proportionate to mouse/human body masses, we titrated the aP from 1/20 to 1/160 of the human dose. Mice receiving 1/80 human aP dose had bacterial burden comparable to those of naive controls. Adding RTX antigen to the 1/80 aP base resulted in enhanced bacterial clearance. Inclusion of RTX induced production of antibodies recognizing RTX, enhanced production of anti-pertussis toxin, decreased secretion of proinflammatory cytokines, such as interleukin-6, and decreased recruitment of total macrophages in the lung. This study shows that adding RTX antigen to an appropriate dose of aP can enhance protection against B. pertussis challenge in mice.
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Affiliation(s)
- Dylan T Boehm
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Jesse M Hall
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Ting Y Wong
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Andrea M DiVenere
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Emel Sen-Kilic
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Justin R Bevere
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Shelby D Bradford
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Catherine B Blackwood
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Cody M Elkins
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
| | - Katherine A DeRoos
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Mary C Gray
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - C Garret Cooper
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
- Department of Medicine, Section of Infectious Diseases, West Virginia University, Morgantown, West Virginia, USA
| | - Melinda E Varney
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Erik L Hewlett
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
| | - F Heath Damron
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
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15
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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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16
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Etxaniz A, González-Bullón D, Martín C, Ostolaza H. Membrane Repair Mechanisms against Permeabilization by Pore-Forming Toxins. Toxins (Basel) 2018; 10:E234. [PMID: 29890730 PMCID: PMC6024578 DOI: 10.3390/toxins10060234] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/04/2018] [Accepted: 06/07/2018] [Indexed: 01/29/2023] Open
Abstract
Permeabilization of the plasma membrane represents an important threat for any cell, since it compromises its viability by disrupting cell homeostasis. Numerous pathogenic bacteria produce pore-forming toxins that break plasma membrane integrity and cause cell death by colloid-osmotic lysis. Eukaryotic cells, in turn, have developed different ways to cope with the effects of such membrane piercing. Here, we provide a short overview of the general mechanisms currently proposed for plasma membrane repair, focusing more specifically on the cellular responses to membrane permeabilization by pore-forming toxins and presenting new data on the effects and cellular responses to the permeabilization by an RTX (repeats in toxin) toxin, the adenylate cyclase toxin-hemolysin secreted by the whooping cough bacterium Bordetella pertussis, which we have studied in the laboratory.
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Affiliation(s)
- Asier Etxaniz
- Biofisika Institute (UPV/EHU, CSIC) and University of the Basque Country (UPV/EHU) Parque Científico s/n, 48940 Leioa, Spain.
| | - David González-Bullón
- Biofisika Institute (UPV/EHU, CSIC) and University of the Basque Country (UPV/EHU) Parque Científico s/n, 48940 Leioa, Spain.
| | - César Martín
- Biofisika Institute (UPV/EHU, CSIC) and University of the Basque Country (UPV/EHU) Parque Científico s/n, 48940 Leioa, Spain.
| | - Helena Ostolaza
- Biofisika Institute (UPV/EHU, CSIC) and University of the Basque Country (UPV/EHU) Parque Científico s/n, 48940 Leioa, Spain.
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Membrane-Active Properties of an Amphitropic Peptide from the CyaA Toxin Translocation Region. Toxins (Basel) 2017; 9:toxins9110369. [PMID: 29135925 PMCID: PMC5705984 DOI: 10.3390/toxins9110369] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 12/28/2022] Open
Abstract
The adenylate cyclase toxin CyaA is involved in the early stages of infection by Bordetella pertussis, the causative agent of whooping cough. CyaA intoxicates target cells by a direct translocation of its catalytic domain (AC) across the plasma membrane and produces supraphysiological levels of cAMP, leading to cell death. The molecular process of AC translocation remains largely unknown, however. We have previously shown that deletion of residues 375–485 of CyaA selectively abrogates AC translocation into eukaryotic cells. We further identified within this “translocation region” (TR), P454 (residues 454–484), a peptide that exhibits membrane-active properties, i.e., is able to bind and permeabilize lipid vesicles. Here, we analyze various sequences from CyaA predicted to be amphipatic and show that although several of these peptides can bind membranes and adopt a helical conformation, only the P454 peptide is able to permeabilize membranes. We further characterize the contributions of the two arginine residues of P454 to membrane partitioning and permeabilization by analyzing the peptide variants in which these residues are substituted by different amino acids (e.g., A, K, Q, and E). Our data shows that both arginine residues significantly contribute, although diversely, to the membrane-active properties of P454, i.e., interactions with both neutral and anionic lipids, helix formation in membranes, and disruption of lipid bilayer integrity. These results are discussed in the context of the translocation process of the full-length CyaA toxin.
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Structure-Function Relationships Underlying the Capacity of Bordetella Adenylate Cyclase Toxin to Disarm Host Phagocytes. Toxins (Basel) 2017; 9:toxins9100300. [PMID: 28946636 PMCID: PMC5666347 DOI: 10.3390/toxins9100300] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/18/2023] Open
Abstract
Bordetellae, pathogenic to mammals, produce an immunomodulatory adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) that enables them to overcome the innate immune defense of the host. CyaA subverts host phagocytic cells by an orchestrated action of its functional domains, where an extremely catalytically active adenylyl cyclase enzyme is delivered into phagocyte cytosol by a pore-forming repeat-in-toxin (RTX) cytolysin moiety. By targeting sentinel cells expressing the complement receptor 3, known as the CD11b/CD18 (αMβ₂) integrin, CyaA compromises the bactericidal functions of host phagocytes and supports infection of host airways by Bordetellae. Here, we review the state of knowledge on structural and functional aspects of CyaA toxin action, placing particular emphasis on signaling mechanisms by which the toxin-produced 3',5'-cyclic adenosine monophosphate (cAMP) subverts the physiology of phagocytic cells.
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Understanding the Mechanism of Translocation of Adenylate Cyclase Toxin across Biological Membranes. Toxins (Basel) 2017; 9:toxins9100295. [PMID: 28934133 PMCID: PMC5666342 DOI: 10.3390/toxins9100295] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/05/2023] Open
Abstract
Adenylate cyclase toxin (ACT) is one of the principal virulence factors secreted by the whooping cough causative bacterium Bordetella pertussis, and it has a critical role in colonization of the respiratory tract and establishment of the disease. ACT targets phagocytes via binding to the CD11b/CD18 integrin and delivers its N-terminal adenylate cyclase (AC) domain directly to the cell cytosol, where it catalyzes unregulated conversion of cytosolic ATP into cAMP upon activation by binding to cellular calmodulin. High cAMP levels disrupt bactericidal functions of the immune cells, ultimately leading to cell death. In spite of its relevance in the ACT biology, the mechanism by which its ≈400 amino acid-long AC domain is transported through the target plasma membrane, and is released into the target cytosol, remains enigmatic. This article is devoted to refresh our knowledge on the mechanism of AC translocation across biological membranes. Two models, the so-called "two-step model" and the recently-proposed "toroidal pore model", will be considered.
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20
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Phospholipase A activity of adenylate cyclase toxin mediates translocation of its adenylate cyclase domain. Proc Natl Acad Sci U S A 2017; 114:E6784-E6793. [PMID: 28760979 DOI: 10.1073/pnas.1701783114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adenylate cyclase toxin (ACT or CyaA) plays a crucial role in respiratory tract colonization and virulence of the whooping cough causative bacterium Bordetella pertussis Secreted as soluble protein, it targets myeloid cells expressing the CD11b/CD18 integrin and on delivery of its N-terminal adenylate cyclase catalytic domain (AC domain) into the cytosol, generates uncontrolled toxic levels of cAMP that ablates bactericidal capacities of phagocytes. Our study deciphers the fundamentals of the heretofore poorly understood molecular mechanism by which the ACT enzyme domain directly crosses the host cell membrane. By combining molecular biology, biochemistry, and biophysics techniques, we discover that ACT has intrinsic phospholipase A (PLA) activity, and that such activity determines AC translocation. Moreover, we show that elimination of the ACT-PLA activity abrogates ACT toxicity in macrophages, particularly at toxin concentrations close to biological reality of bacterial infection. Our data support a molecular mechanism in which in situ generation of nonlamellar lysophospholipids by ACT-PLA activity into the cell membrane would form, likely in combination with membrane-interacting ACT segments, a proteolipidic toroidal pore through which AC domain transfer could directly take place. Regulation of ACT-PLA activity thus emerges as novel target for therapeutic control of the disease.
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Kurehong C, Kanchanawarin C, Powthongchin B, Prangkio P, Katzenmeier G, Angsuthanasombat C. Functional Contributions of Positive Charges in the Pore-Lining Helix 3 of the Bordetella pertussis CyaA-Hemolysin to Hemolytic Activity and Ion-Channel Opening. Toxins (Basel) 2017; 9:toxins9030109. [PMID: 28300777 PMCID: PMC5371864 DOI: 10.3390/toxins9030109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 01/14/2023] Open
Abstract
The Bordetella pertussis CyaA-hemolysin (CyaA-Hly) domain was previously demonstrated to be an important determinant for hemolysis against target erythrocytes and ion-channel formation in planar lipid bilayers (PLBs). Here, net-charge variations in the pore-lining helix of thirteen related RTX cytolysins including CyaA-Hly were revealed by amino acid sequence alignments, reflecting their different degrees of hemolytic activity. To analyze possible functional effects of net-charge alterations on hemolytic activity and channel formation of CyaA-Hly, specific mutations were made at Gln574 or Glu581 in its pore-lining α3 of which both residues are highly conserved Lys in the three highly active RTX cytolysins (i.e., Escherichia coli α-hemolysin, Actinobacillus pleuropneumoniae toxin, and Aggregatibacter actinomycetemcomitans leukotoxin). All six constructed CyaA-Hly mutants that were over-expressed in E. coli as 126 kDa His-tagged soluble proteins were successfully purified via immobilized Ni2+-affinity chromatography. Both positive-charge substitutions (Q574K, Q574R, E581K, E581R) and negative-charge elimination (E581Q) appeared to increase the kinetics of toxin-induced hemolysis while the substitution with a negatively-charged side-chain (Q574E) completely abolished its hemolytic activity. When incorporated into PLBs under symmetrical conditions (1.0 M KCl, pH 7.4), all five mutant toxins with the increased hemolytic activity produced clearly-resolved single channels with higher open probability and longer lifetime than the wild-type toxin, albeit with a half decrease in their maximum conductance. Molecular dynamics simulations for 50 ns of a trimeric CyaA-Hly pore model comprising three α2-loop-α3 transmembrane hairpins revealed a significant role of the positive charge at both target positions in the structural stability and enlarged diameter of the simulated pore. Altogether, our present data have disclosed functional contributions of positively-charged side-chains substituted at positions Gln574 and Glu581 in the pore-lining α3 to the enhanced hemolytic activity and ion-channel opening of CyaA-Hly that actually mimics the highly-active RTX (repeat-in-toxin) cytolysins.
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Affiliation(s)
- Chattip Kurehong
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
| | - Chalermpol Kanchanawarin
- Laboratory of Theoretical and Computational Biophysics, Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
| | - Busaba Powthongchin
- Department of Biopharmacy, Faculty of Pharmacy, Silpakorn University, Nakornpathom 73000, Thailand.
| | - Panchika Prangkio
- Division of Biochemistry and Biochemical Technology, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
| | - Gerd Katzenmeier
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
| | - Chanan Angsuthanasombat
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
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22
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Cannella SE, Ntsogo Enguéné VY, Davi M, Malosse C, Sotomayor Pérez AC, Chamot-Rooke J, Vachette P, Durand D, Ladant D, Chenal A. Stability, structural and functional properties of a monomeric, calcium-loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis. Sci Rep 2017; 7:42065. [PMID: 28186111 PMCID: PMC5301233 DOI: 10.1038/srep42065] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/04/2017] [Indexed: 12/21/2022] Open
Abstract
Bordetella pertussis, the causative agent of whooping cough, secretes an adenylate cyclase toxin, CyaA, which invades eukaryotic cells and alters their physiology by cAMP overproduction. Calcium is an essential cofactor of CyaA, as it is the case for most members of the Repeat-in-ToXins (RTX) family. We show that the calcium-bound, monomeric form of CyaA, hCyaAm, conserves its permeabilization and haemolytic activities, even in a fully calcium-free environment. In contrast, hCyaAm requires sub-millimolar calcium in solution for cell invasion, indicating that free calcium in solution is involved in the CyaA toxin translocation process. We further report the first in solution structural characterization of hCyaAm, as deduced from SAXS, mass spectrometry and hydrodynamic studies. We show that hCyaAm adopts a compact and stable state that can transiently conserve its conformation even in a fully calcium-free environment. Our results therefore suggest that in hCyaAm, the C-terminal RTX-domain is stabilized in a high-affinity calcium-binding state by the N-terminal domains while, conversely, calcium binding to the C-terminal RTX-domain strongly stabilizes the N-terminal regions. Hence, the different regions of hCyaAm appear tightly connected, leading to stabilization effects between domains. The hysteretic behaviour of CyaA in response to calcium is likely shared by other RTX cytolysins.
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Affiliation(s)
- Sara E. Cannella
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Marilyne Davi
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Christian Malosse
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Alexandre Chenal
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
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23
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Iwaki M, Konda T. Adenylate cyclase toxin-mediated delivery of the S1 subunit of pertussis toxin into mammalian cells. Pathog Dis 2015; 74:ftv110. [PMID: 26607401 DOI: 10.1093/femspd/ftv110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2015] [Indexed: 11/14/2022] Open
Abstract
The adenylate cyclase toxin (ACT) of Bordetella pertussis internalizes its catalytic domain into target cells. ACT can function as a tool for delivering foreign protein antigen moieties into immune effector cells to induce a cytotoxic T lymphocyte response. In this study, we replaced the catalytic domain of ACT with an enzymatically active protein moiety, the S1 (ADP-ribosyltransferase) subunit of pertussis toxin (PT). The S1 moiety was successfully internalized independent of endocytosis into sheep erythrocytes. The introduced polypeptide exhibited ADP-ribosyltransferase activity in CHO cells and induced clustering typical to PT. The results indicate that ACT can act as a vehicle for not only epitopes but also enzymatically active peptides to mammalian cells.
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Affiliation(s)
- Masaaki Iwaki
- Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Toshifumi Konda
- Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
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24
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Benz R. Channel formation by RTX-toxins of pathogenic bacteria: Basis of their biological activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:526-37. [PMID: 26523409 DOI: 10.1016/j.bbamem.2015.10.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/10/2015] [Accepted: 10/28/2015] [Indexed: 12/15/2022]
Abstract
The pore-forming cytolysins of the RTX-toxin (Repeats in ToXin) family are a relatively small fraction of a steadily increasing family of proteins that contain several functionally important glycine-rich and aspartate containing nonapeptide repeats. These cytolysins produced by a variety of Gram-negative bacteria form ion-permeable channels in erythrocytes and other eukaryotic cells. Hemolytic and cytolytic RTX-toxins represent pathogenicity factors of the toxin-producing bacteria and are very often important key factors in pathogenesis of the bacteria. Channel formation by RTX-toxins lead to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. Here we discuss channel formation and channel properties of some of the best known RTX-toxins, such as α-hemolysin (HlyA) of Escherichia coli and the uropathogenic EHEC strains, the adenylate cyclase toxin (ACT, CyaA) of Bordetella pertussis and the RTX-toxins (ApxI, ApxII and ApxIII) produced by different strains of Actinobacillus pleuropneumoniae. The channels formed by these RTX-toxins in lipid bilayers share some common properties such as cation selectivity and voltage-dependence. Furthermore the channels are transient and show frequent switching between different ion-conducting states. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759, Bremen, Germany.
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25
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Masin J, Osicka R, Bumba L, Sebo P. Bordetella adenylate cyclase toxin: a unique combination of a pore-forming moiety with a cell-invading adenylate cyclase enzyme. Pathog Dis 2015; 73:ftv075. [PMID: 26391732 DOI: 10.1093/femspd/ftv075] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2015] [Indexed: 12/30/2022] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) is a key virulence factor of the whooping cough agent Bordetella pertussis. CyaA targets myeloid phagocytes expressing the complement receptor 3 (CR3, known as αMβ2 integrin CD11b/CD18 or Mac-1) and translocates by a poorly understood mechanism directly across the cytoplasmic membrane into cell cytosol of phagocytes an adenylyl cyclase(AC) enzyme. This binds intracellular calmodulin and catalyzes unregulated conversion of cytosolic ATP into cAMP. Among other effects, this yields activation of the tyrosine phosphatase SHP-1, BimEL accumulation and phagocyte apoptosis induction. In parallel, CyaA acts as a cytolysin that forms cation-selective pores in target membranes. Direct penetration of CyaA into the cytosol of professional antigen-presenting cells allows the use of an enzymatically inactive CyaA toxoid as a tool for delivery of passenger antigens into the cytosolic pathway of processing and MHC class I-restricted presentation, which can be exploited for induction of antigen-specific CD8(+) cytotoxic T-lymphocyte immune responses.
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Affiliation(s)
- Jiri Masin
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Radim Osicka
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Ladislav Bumba
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Peter Sebo
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
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26
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Bárcena-Uribarri I, Benz R, Winterhalter M, Zakharian E, Balashova N. Pore forming activity of the potent RTX-toxin produced by pediatric pathogen Kingella kingae: Characterization and comparison to other RTX-family members. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1536-44. [PMID: 25858109 DOI: 10.1016/j.bbamem.2015.03.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 12/18/2022]
Abstract
Pediatric septic arthritis in patients under age of four is frequently caused by the oral Gram-negative bacterium Kingella kingae. This organism may be responsible for a severe form of infective endocarditis in otherwise healthy children and adults. A major virulence factor of K. kingae is RtxA, a toxin that belongs to the RTX (Repeats-in-ToXin) group of secreted pore forming toxins. To understand the RtxA effects on host cell membranes, the toxin activity was studied using planar lipid bilayers. K. kingae strain PYKK081 and its isogenic RtxA-deficient strain, KKNB100, were tested for their ability to form pores in artificial membranes of asolectin/n-decane. RtxA, purified from PYKK081, was able to rapidly form pores with an apparent diameter of 1.9nm as measured by the partition of nonelectrolytes in the pores. The RtxA channels are cation-selective and showed strong voltage-dependent gating. In contrast to supernatants of PYKK081, those of KKNB100 did not show any pore forming activity. We concluded that RtxA toxin is the only secreted protein from K. kingae forming large channels in host cell membranes where it induces cation flux leading to programmed cell death. Furthermore, our findings suggested that the planar lipid bilayer technique can effectively be used to test possible inhibitors of RTX toxin activity and to investigate the mechanism of the toxin binding to the membrane.
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Affiliation(s)
| | - Roland Benz
- Department of Life Science and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Mathias Winterhalter
- Department of Life Science and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Eleonora Zakharian
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, USA
| | - Nataliya Balashova
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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27
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Quantification of potassium levels in cells treated with Bordetella adenylate cyclase toxin. Anal Biochem 2014; 450:57-62. [DOI: 10.1016/j.ab.2013.10.039] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/07/2013] [Accepted: 10/28/2013] [Indexed: 12/28/2022]
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28
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Differences in purinergic amplification of osmotic cell lysis by the pore-forming RTX toxins Bordetella pertussis CyaA and Actinobacillus pleuropneumoniae ApxIA: the role of pore size. Infect Immun 2013; 81:4571-82. [PMID: 24082076 DOI: 10.1128/iai.00711-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A large subgroup of the repeat in toxin (RTX) family of leukotoxins of Gram-negative pathogens consists of pore-forming hemolysins. These can permeabilize mammalian erythrocytes (RBCs) and provoke their colloid osmotic lysis (hemolytic activity). Recently, ATP leakage through pannexin channels and P2X receptor-mediated opening of cellular calcium and potassium channels were implicated in cell permeabilization by pore-forming toxins. In the study described here, we examined the role played by purinergic signaling in the cytolytic action of two RTX toxins that form pores of different sizes. The cytolytic potency of ApxIA hemolysin of Actinobacillus pleuropneumoniae, which forms pores about 2.4 nm wide, was clearly reduced in the presence of P2X7 receptor antagonists or an ATP scavenger, such as pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), Brilliant Blue G, ATP oxidized sodium salt, or hexokinase. In contrast, antagonists of purinergic signaling had no impact on the hemolytic potency of the adenylate cyclase toxin-hemolysin (CyaA) of Bordetella pertussis, which forms pores of 0.6 to 0.8 nm in diameter. Moreover, the conductance of pores formed by ApxIA increased with the toxin concentration, while the conductance of the CyaA single pore units was constant at various toxin concentrations. However, the P2X7 receptor antagonist PPADS inhibited in a concentration-dependent manner the exacerbated hemolytic activity of a CyaA-ΔN489 construct (lacking 489 N-terminal residues of CyaA), which exhibited a strongly enhanced pore-forming propensity (>20-fold) and also formed severalfold larger conductance units in planar lipid bilayers than intact CyaA. These results point to a pore size threshold of purinergic amplification involvement in cell permeabilization by pore-forming RTX toxins.
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29
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Brown AC, Boesze-Battaglia K, Du Y, Stefano FP, Kieba IR, Epand RF, Kakalis L, Yeagle PL, Epand RM, Lally ET. Aggregatibacter actinomycetemcomitans leukotoxin cytotoxicity occurs through bilayer destabilization. Cell Microbiol 2012; 14:869-81. [PMID: 22309134 DOI: 10.1111/j.1462-5822.2012.01762.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Gram-negative bacterium, Aggregatibacter actinomycetemcomitans, is a common inhabitant of the human upper aerodigestive tract. The organism produces an RTX (Repeats in ToXin) toxin (LtxA) that kills human white blood cells. LtxA is believed to be a membrane-damaging toxin, but details of the cell surface interaction for this and several other RTX toxins have yet to be elucidated. Initial morphological studies suggested that LtxA was bending the target cell membrane. Because the ability of a membrane to bend is a function of its lipid composition, we assessed the proficiency of LtxA to release of a fluorescent dye from a panel of liposomes composed of various lipids. Liposomes composed of lipids that form nonlamellar phases were susceptible to LtxA-induced damage while liposomes composed of lipids that do not form non-bilayer structures were not. Differential scanning calorimetry demonstrated that the toxin decreased the temperature at which the lipid transitions from a bilayer to a nonlamellar phase, while (31) P nuclear magnetic resonance studies showed that the LtxA-induced transition from a bilayer to an inverted hexagonal phase occurs through the formation of an isotropic intermediate phase. These results indicate that LtxA cytotoxicity occurs through a process of membrane destabilization.
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Affiliation(s)
- Angela C Brown
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104, USA
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30
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Pojanapotha P, Thamwiriyasati N, Powthongchin B, Katzenmeier G, Angsuthanasombat C. Bordetella pertussis CyaA-RTX subdomain requires calcium ions for structural stability against proteolytic degradation. Protein Expr Purif 2010; 75:127-32. [PMID: 20691271 DOI: 10.1016/j.pep.2010.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 07/25/2010] [Accepted: 07/30/2010] [Indexed: 10/19/2022]
Abstract
Previously, the 126-kDa Bordetella pertussis CyaA pore-forming (CyaA-PF) domain expressed in Escherichia coli was shown to retain its hemolytic activity. Here, a 100-kDa RTX (Repeat-in-ToXin) subcloned fragment (CyaA-RTX) containing a number of putative calcium-binding repeats was further investigated. The recombinant CyaA-RTX protein, although expressed as a soluble form in a protease-deficient E. coli strain BL21(DE3)pLysS, was found to be highly sensitive to proteolytic degradation. Interestingly, the addition of calcium ions in a millimolar range into the CyaA-RTX preparation significantly prevented the degradation. Moreover, levels of proteolytic degradation were dependent on calcium concentrations, implying an important role for calcium-binding sites in the RTX subdomain for structural stability. Homology-based modeling of the repetitive blocks in the CyaA-RTX subdomain supports that this calcium-bound protein folds into a parallel β-roll structure with calcium ions acting as a structural stabilizing bridge.
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Affiliation(s)
- Pichaya Pojanapotha
- Laboratory of Molecular Biophysics and Structural Biochemistry, Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
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31
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Adenylate cyclase toxin translocates across target cell membrane without forming a pore. Mol Microbiol 2010; 75:1550-62. [DOI: 10.1111/j.1365-2958.2010.07077.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Abstract
Bacterial toxins damage the host at the site of bacterial infection or distant from the site. Bacterial toxins can be single proteins or oligomeric protein complexes that are organized with distinct AB structure-function properties. The A domain encodes a catalytic activity. ADP ribosylation of host proteins is the earliest post-translational modification determined to be performed by bacterial toxins; other modifications include glucosylation and proteolysis. Bacterial toxins also catalyze the non-covalent modification of host protein function or can modify host cell properties through direct protein-protein interactions. The B domain includes two functional domains: a receptor-binding domain, which defines the tropism of a toxin for a cell and a translocation domain that delivers the A domain across a lipid bilayer, either on the plasma membrane or the endosome. Bacterial toxins are often characterized based upon the secretion mechanism that delivers the toxin out of the bacterium, termed types I-VII. This review summarizes the major families of bacterial toxins and also describes the specific structure-function properties of the botulinum neurotoxins.
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Affiliation(s)
- James S Henkel
- Medical College of Wisconsin, Department of Microbiology and Molecular Genetics, Milwaukee, WI 53151, USA.
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33
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Vojtova-Vodolanova J, Basler M, Osicka R, Knapp O, Maier E, Cerny J, Benada O, Benz R, Sebo P. Oligomerization is involved in pore formation by
Bordetella
adenylate cyclase toxin. FASEB J 2009; 23:2831-43. [DOI: 10.1096/fj.09-131250] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Marek Basler
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Radim Osicka
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Oliver Knapp
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Elke Maier
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Jan Cerny
- Department of Cell Biology Faculty of Science Charles University Prague Czech Republic
| | - Oldrich Benada
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Roland Benz
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Peter Sebo
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
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34
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Fiser R, Konopásek I. Different modes of membrane permeabilization by two RTX toxins: HlyA from Escherichia coli and CyaA from Bordetella pertussis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1249-54. [PMID: 19348784 DOI: 10.1016/j.bbamem.2009.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/18/2009] [Accepted: 03/29/2009] [Indexed: 11/15/2022]
Abstract
This study clarifies the membrane disruption mechanisms of two bacterial RTX toxins: alphahemolysin (HlyA) from Escherichia coli and a highly homologous adenylate cyclase toxin (CyaA) from Bordetella pertussis. For this purpose, we employed a fluorescence requenching method using liposomes (extruded through filters of different pore size - 1000 nm, 400 nm or 100 nm) with encapsulated fluorescent dye/quencher pair ANTS/DPX. We showed that both toxins induced a graded leakage of liposome content with different selectivities alpha for DPX and ANTS. In contrast to HlyA, CyaA exhibited a higher selectivity for cationic quencher DPX, which increased with vesicle diameter. Large unilamellar vesicles (LUV(1000)) were found to be more suitable for distinguishing between high alpha values whereas smaller ones (LUV(100)) were more appropriate for discriminating an all-or-none leakage (alpha=0) from the graded leakage with low values of alpha. While disrupting LUV(1000), CyaA caused a highly cation-selective leakage (alpha~15) whereas its mutated form with decreased channel K(+)/Cl(-) selectivity due to two substitutions in a predicted transmembrane segment (CyaA-E509K+E516K) exhibited much lower selectivity (alpha approximately 6). We concluded that the fluorescence requenching method in combination with different size of liposomes is a valuable tool for characterization of pore-forming toxins and their variants.
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Affiliation(s)
- Radovan Fiser
- Department of Genetics, Faculty of Science, Charles University in Prague, Vinicná 5, CZ-128 44, Prague 2, Czech Republic.
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35
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Cheung GYC, Kelly SM, Jess TJ, Prior S, Price NC, Parton R, Coote JG. Functional and structural studies on different forms of the adenylate cyclase toxin of Bordetella pertussis. Microb Pathog 2008; 46:36-42. [PMID: 18992319 DOI: 10.1016/j.micpath.2008.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 10/02/2008] [Accepted: 10/07/2008] [Indexed: 12/23/2022]
Abstract
A comparison was made of the cytotoxic activity and secondary structural features of four recombinant forms of adenylate cyclase toxin (CyaA). These forms were fully functional CyaA, CyaA lacking adenylate cyclase enzymatic activity (CyaA*), and non-acylated forms of these toxins, proCyaA and proCyaA*. At a toxin concentration>1 microg/ml, CyaA* was as cytotoxic towards J774.2 cells as CyaA and mediated cell killing at a faster rate than CyaA. At concentrations<0.5 microg/ml, CyaA* was less cytotoxic than CyaA and, at <0.1 microg/ml of CyaA*, no activity was detected. CyaA, but not CyaA*, was able to induce caspase 3/7 activity, a measure of apoptosis. ProCyaA and proCyaA* had no detectable cytotoxic or apoptotic activity. CyaA caused 50% inhibition of the zymosan-stimulated oxidative burst at 0.003 microg/ml, whereas a approximately 500-fold greater toxin concentration of CyaA* or proCyaA was needed for 50% inhibition. ProCyaA* was inactive. CyaA is a calcium-binding protein and far UV circular dichroism (CD), near UV CD and fluorescence spectra analyses showed that all the forms of CyaA had similar overall structures at different calcium concentrations up to 5.0 mM. At 7.5 mM CaCl2, the far UV spectrum of CyaA altered significantly, indicating a change in secondary structure associated with high beta-sheet content or a beta-aggregated state, whereas the spectrum of CyaA* showed only a slight alteration at this calcium concentration. Near UV CD and fluorescence studies were consistent with a rearrangement of secondary structural elements in the presence of CaCl2 for all CyaA forms. There was a marked dependence on protein concentration of the far UV spectra of these CyaA forms, implying an interaction between individual molecules at higher protein concentrations.
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Affiliation(s)
- Gordon Y C Cheung
- Division of Infection and Immunity, University of Glasgow, Institute of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, 120 University Place, Glasgow G12 8TA, UK
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36
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Powthongchin B, Angsuthanasombat C. Effects on haemolytic activity of single proline substitutions in the Bordetella pertussis CyaA pore-forming fragment. Arch Microbiol 2008; 191:1-9. [DOI: 10.1007/s00203-008-0421-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 07/21/2008] [Accepted: 07/22/2008] [Indexed: 01/12/2023]
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37
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Barshteyn N, Elfarra AA. Detection of multiple globin monoadducts and cross-links after in vitro exposure of rat erythrocytes to S-(1,2-dichlorovinyl)-L-cysteine sulfoxide and after in vivo treatment of rats with S-(1,2-dichlorovinyl)-L-cysteine sulfoxide. Chem Res Toxicol 2008; 21:1716-25. [PMID: 18681461 DOI: 10.1021/tx800060z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
S-(1,2-dichlorovinyl)- L-cysteine sulfoxide (DCVCS), a Michael acceptor produced by an FMO3-mediated oxidation of the trichloroethylene metabolite S-(1,2-dichlorovinyl)- L-cysteine (DCVC), is a more potent nephrotoxicant than DCVC. Because DCVCS incubations with N-acetyl- L-cysteine at pH 7.4, 37 degrees C resulted in the formation of three diastereomeric monoadducts and one diadduct, globin monoadducts and cross-links formed after in vitro incubations of rat erythrocytes with DCVCS (0.9-450 microM) for 2 h and those present at 30 min after in vivo treatment of rats with DCVCS (23 and 230 micromol/kg) were characterized. ESI/MS of intact globin chains revealed adduction of 1 DCVCS moiety on the beta2 chain at the three lowest DCVCS concentrations and on the beta1 chain after the in vivo treatment with 230 micromol/kg DCVCS. Interestingly, intact globin dimers and trimers were detectable by ESI/MS with all DCVCS concentrations in vitro (also by SDS-PAGE) and in vivo. LC/MS and MALDI/FTICR of trypsin digested peptides from globin samples obtained after in vitro (450 microM DCVCS) or in vivo exposure to DCVCS (230 micromol/kg) suggested the formation of DCVCS monoadducts not only with Cys93 and Cys125 of the beta chains but also with Cys13 of the alpha chains, whereas no monoadducted peptides were detected at lower DCVCS concentrations in vitro or in vivo. However, LC/MS and MALDI-TOF/TOF suggested the presence of several DCVCS-derived peptide cross-links both in vivo and in vitro at all DCVCS exposure levels. Collectively, the results indicate at least 4 out of the 5 cysteine moieties of the rat hemoglobin heterodimer may be alkylated by DCVCS, in reactions that could also lead to the formation of multiple cross-links. DCVCS- and N-acetyl-DCVCS (NA-DCVCS)-derived globin cross-links containing GSH and Cys were also detected by mass spectrometry, providing strong evidence for the reactivity and/or cross-linking ability of DCVCS, NA-DCVCS, and their GSH or Cys conjugates in both the in vitro and the in vivo. Thus, hemoglobin adducts and cross-links may be useful biomarkers to investigate the possible presence of DCVCS in circulation after DCVC or trichloroethylene exposure.
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Affiliation(s)
- Nella Barshteyn
- Department of Comparative Biosciences, Division of Pharmaceutical Sciences, University of Wisconsin, Madison, Wisconsin 53706-1102, USA
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Knapp O, Maier E, Mašín J, Šebo P, Benz R. Pore formation by the Bordetella adenylate cyclase toxin in lipid bilayer membranes: Role of voltage and pH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:260-9. [DOI: 10.1016/j.bbamem.2007.09.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 09/25/2007] [Accepted: 09/27/2007] [Indexed: 11/25/2022]
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Watanabe M, Connelly B, Weiss AA. Characterization of serological responses to pertussis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2006; 13:341-8. [PMID: 16522775 PMCID: PMC1391967 DOI: 10.1128/cvi.13.3.341-348.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have compared the use of five nonvaccine antigens to the use of conventional vaccine antigens, pertussis toxin (PT), and filamentous hemagglutinin (FHA) for the serological diagnosis of pertussis by enzyme-linked immunosorbent assay (ELISA). The nonvaccine antigens included the catalytic region of adenylate cyclase toxin (CatACT), the C-terminal region of FHA (C-FHA), lipooligosaccharide (LOS), the peptidoglycan-associated lipoprotein (PAL), and the BrkA protein. The serological responses of individuals with culture-confirmed pertussis were compared to those of adults with no recent history of a coughing disease. An immunoglobulin G (IgG) ELISA for PT was the most sensitive (92.2%) test for the serodiagnosis of pertussis. Of the nonvaccine antigens, ELISA for IgG responses to CatACT (sensitivity, 62.8%), C-FHA (sensitivity, 39.2%), and LOS IgA (sensitivity, 29.4%) were less sensitive but could also distinguish culture-positive individuals from control individuals. The use of a combination of multiple ELISA targets improved the sensitivity of the assay for serological diagnosis. Elevated IgG and IgA antibody titers persisted for more than a year in the individuals with culture-confirmed pertussis.
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Affiliation(s)
- Mineo Watanabe
- Department of Molecular Genetics, Biochemistry, and Microbiology, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA
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Hewlett EL, Donato GM, Gray MC. Macrophage cytotoxicity produced by adenylate cyclase toxin from Bordetella pertussis: more than just making cyclic AMP! Mol Microbiol 2006; 59:447-59. [PMID: 16390441 DOI: 10.1111/j.1365-2958.2005.04958.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cytotoxic effect of adenylate cyclase (AC) toxin from Bordetella pertussis on host cells has been attributed to the production of supraphysiologic levels of cyclic AMP by the toxin. We have tested this hypothesis and show that at least two different mechanisms, cAMP accumulation/ATP depletion and oligomerization/pore formation, contribute, perhaps synergistically, to AC toxin-induced cytotoxicity. Wild-type (WT) AC toxin causes cell death associated with an increase in cAMP, a reduction in ATP, activation of caspases 3/7, and increased annexin V and TUNEL staining. In contrast, a non-acylated, enzymatically active, non-haemolytic form of AC toxin is able to increase cAMP, reduce ATP and elicit annexin V staining, but the decrease in ATP and the annexin staining are transient and there is minimal caspase activation, TUNEL staining and cell death. Mutant AC toxins defective in either enzymatic activity or the ability to deliver their enzymatic domain are able to kill J774 cells, without cAMP production, and with minimal caspase activation and TUNEL staining. Comparison of the potencies of WT toxin and those of mutants that only increase cAMP or only create transmembrane pores establishes that at least two mechanisms are contributory and that simply the production of cAMP is not enough to account for the cytotoxicity produced by AC toxin.
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Affiliation(s)
- Erik L Hewlett
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia School of Medicine, Box 800419, Charlottesville, 22908, USA.
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Vojtová J, Kofronová O, Sebo P, Benada O. Bordetella adenylate cyclase toxin induces a cascade of morphological changes of sheep erythrocytes and localizes into clusters in erythrocyte membranes. Microsc Res Tech 2006; 69:119-29. [PMID: 16456835 DOI: 10.1002/jemt.20277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adenylate cyclase toxin (CyaA) of Bordetella pertussis penetrates the membrane of eukaryotic cells, producing high levels of intracellular cAMP, as well as hemolysis that results from the formation of cation-selective toxin channels in the membrane. Using several microscopical approaches we studied the effects of CyaA action on the morphology of sheep erythrocytes during early phases preceding lysis and examined localization of CyaA molecules within the erythrocyte membrane. CyaA induced a cascade of morphological changes of erythrocytes, such as shrinkage, formation of membrane projections, and blebs and swelling. The use of an enzymatically inactive CyaA-AC- toxoid that is unable to produce cAMP and of a CyaA-E581K mutant exhibiting higher hemolytic activity than with CyaA showed that the hemolytic activity is responsible for the induction of morphological changes of erythrocytes. Further, immunolabeling of inserted CyaA-232/FLAG molecules with specific anti-FLAG antibodies and IgG-gold particles indicated a clustered distribution of CyaA molecules in erythrocyte membrane. This was confirmed by immunofluorescence and confocal microscopy, which revealed uniform stoichiometry of CyaA clusters, suggesting CyaA binding into specific domains in erythrocyte membrane. Indeed, a decrease of CyaA binding after cholesterol depletion of erythrocytes suggests toxin targeting and binding to membrane microdomains (rafts).
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Affiliation(s)
- Jana Vojtová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague 4, Czech Republic
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Basler M, Masin J, Osicka R, Sebo P. Pore-forming and enzymatic activities of Bordetella pertussis adenylate cyclase toxin synergize in promoting lysis of monocytes. Infect Immun 2006; 74:2207-14. [PMID: 16552051 PMCID: PMC1418931 DOI: 10.1128/iai.74.4.2207-2214.2006] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bordetella adenylate cyclase (AC) toxin-hemolysin (CyaA) targets myeloid phagocytes expressing the alphaMbeta2 integrin (CD11b/CD18) and delivers into their cytosol an AC enzyme that converts ATP into cyclic AMP (cAMP). In parallel, CyaA acts as a hemolysin, forming small membrane pores. Using specific mutations, we dissected the contributions of the two activities to cytolytic potency of CyaA on J774A.1 murine monocytes. The capacity of AC to penetrate cells and deplete cytosolic ATP was essential for promoting lysis and the enzymatically inactive but fully hemolytic CyaA-AC- toxoid exhibited a 15-fold-lower cytolytic capacity on J774A.1 cells than intact CyaA. Moreover, a two- or fourfold drop of specific hemolytic activity of the CyaA-E570Q and CyaA-E581P mutants was overpowered by an intact capacity to dissipate cytosolic ATP into cAMP, allowing the less hemolytic proteins to promote lysis of J774A.1 cells as efficiently as intact CyaA. However, an increased hemolytic activity, due to lysine substitutions of glutamates 509, 516, and 581 in the pore-forming domain, conferred on AC- toxoids a correspondingly enhanced cytolytic potency. Moreover, a threefold increase in hemolytic activity could override a fourfold drop in capacity to convert cellular ATP to cAMP, conferring on the CyaA-E581K construct an overall twofold increased cytolytic potency. Hence, although appearing auxiliary in cytolytic action of the toxin on nucleated cells, the pore-forming activity can synergize with ATP-depleting activity of the cell-invasive AC enzyme and complement its action toward maximal cytotoxicity.
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Affiliation(s)
- Marek Basler
- Institute of Microbiology CAS, Videnska 1083, CZ-142 20 Prague 4, Czech Republic
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Donato GM, Hsia HLJ, Green CS, Hewlett EL. Adenylate cyclase toxin (ACT) from Bordetella hinzii: characterization and differences from ACT of Bordetella pertussis. J Bacteriol 2005; 187:7579-88. [PMID: 16267282 PMCID: PMC1280298 DOI: 10.1128/jb.187.22.7579-7588.2005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bordetella hinzii is a commensal respiratory microorganism in poultry but is increasingly being recognized as an opportunistic pathogen in immunocompromised humans. Although associated with a variety of disease states, practically nothing is known about the mechanisms employed by this bacterium. In this study, we show by DNA sequencing and reverse transcription-PCR that both commensal and clinical strains of B. hinzii possess and transcriptionally express cyaA, the gene encoding adenylate cyclase toxin (ACT) in other pathogenic Bordetella species. By Western blotting, we also found that B. hinzii produces full-length ACT protein in quantities that are comparable to those made by B. pertussis. In contrast to B. pertussis ACT, however, ACT from B. hinzii is less extractable from whole bacteria, nonhemolytic, has a 50-fold reduction in adenylate cyclase activity, and is unable to elevate cyclic AMP levels in host macrophages (nontoxic). The decrease in enzymatic activity is attributable, at least in part, to a decreased binding affinity of B. hinzii ACT for calmodulin, the eukaryotic activator of B. pertussis ACT. In addition, we demonstrate that the lack of intoxication by B. hinzii ACT may be due to the absence of expression of cyaC, the gene encoding the accessory protein required for the acylation of B. pertussis ACT. These results demonstrate the expression of ACT by B. hinzii and represent the first characterization of a potential virulence factor of this organism.
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MESH Headings
- Adenylate Cyclase Toxin/analysis
- Adenylate Cyclase Toxin/genetics
- Adenylate Cyclase Toxin/isolation & purification
- Adenylate Cyclase Toxin/toxicity
- Animals
- Bacterial Proteins/analysis
- Bacterial Proteins/genetics
- Bacterial Proteins/isolation & purification
- Bacterial Proteins/toxicity
- Blotting, Western
- Bordetella/enzymology
- Bordetella/genetics
- Calmodulin/metabolism
- Cell Line
- Cyclic AMP/analysis
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- Gene Expression
- Hemolysis
- Macrophages/microbiology
- Mice
- Molecular Sequence Data
- Protein Binding
- RNA, Bacterial/analysis
- RNA, Messenger/analysis
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Virulence Factors, Bordetella/analysis
- Virulence Factors, Bordetella/genetics
- Virulence Factors, Bordetella/isolation & purification
- Virulence Factors, Bordetella/toxicity
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Affiliation(s)
- Gina M Donato
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia School of Medicine, Charlottesville, 22908, USA
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Lee SJ, Gray MC, Zu K, Hewlett EL. Oligomeric behavior of Bordetella pertussis adenylate cyclase toxin in solution. Arch Biochem Biophys 2005; 438:80-7. [PMID: 15878155 DOI: 10.1016/j.abb.2005.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 03/31/2005] [Accepted: 04/02/2005] [Indexed: 10/25/2022]
Abstract
Adenylate cyclase (AC) toxin from Bordetella pertussis inserts into eukaryotic cells, producing intracellular cAMP, as well as hemolysis and cytotoxicity. Concentration dependence of hemolysis suggests oligomers as the functional unit and inactive deletion mutants permit partial restoration of intoxication and/or hemolysis, when added in pairs [M. Iwaki, A. Ullmann, P. Sebo, Mol. Microbiol. 17 (1995) 1015-1024], suggesting dimerization/oligomerization. Using affinity co-precipitation and fluorescence resonance energy transfer (FRET), we demonstrate specific self-association of AC toxin molecules in solution. Flag-tagged AC toxin mixed with biotinylated-AC toxin, followed by streptavidin beads, yields both forms of the toxin. FRET measurements of toxin, labeled with different fluorophores, demonstrate association in solution, requiring post-translational acylation, but not calcium. AC toxin mixed with DeltaR, an inactive mutant, results in enhancement of hemolysis over that with wild type alone, suggesting that oligomers are functional. Dimers and perhaps higher molecular mass forms of AC toxin occur in solution in a manner that is relevant to toxin action.
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Affiliation(s)
- Sang-Jin Lee
- University of Virginia, Department of Pharmacology, Charlottesville, VA 22903, USA
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Chun YS, Yeo EJ, Suh HJ, Park JW. Spontaneous generation of reactive oxygen species in the mixture of cyanide and glycerol. Ann N Y Acad Sci 2005; 1030:43-51. [PMID: 15659779 DOI: 10.1196/annals.1329.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Reactive oxygen species are involved in tumor promotion or apoptosis. In assaying prooxidant or antioxidant activities, cyanide has been commonly used as an inhibitor of mitochondrial oxidases, peroxidases, or Cu,Zn-superoxide dismutase, which have an influence on intracellular levels of reactive oxygen species. It has also been used to chemically mimic hypoxia. On the other hand, glycerol has been widely used as a stabilizer of various enzymes. In particular, glycerol is required to maintain the enzymatic activities of membrane-bound NAD(P)H oxidases extracted from surrounding phospholipids. Since both cyanide and glycerol are relatively inert, they have been used concomitantly regardless of any mutual interference. In this study, we demonstrate that a mixture of glycerol and cyanide reduced cytochrome c and nitroblue tetrazolium, both of which are superoxide anion indicators. The mixture also enhanced the production of superoxide anion in the presence of redox-cycling compounds. Superoxide production by the mixture was confirmed by electron spin resonance spectra. Moreover, the mixture induced lipid peroxidation and hemolysis in human erythrocytes. These results suggest that cyanide and glycerol should be used carefully in reaction systems used to measure superoxide production or antioxidant activity. However, sucrose and sodium azide in combination do not produce such artifacts and thus may be used as an alternative.
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Affiliation(s)
- Yang-Sook Chun
- Department of Pharmacology and Cancer Research Institute, Seoul National University, College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799 Korea
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46
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Cherry JD, Xing DXL, Newland P, Patel K, Heininger U, Corbel MJ. Determination of Serum Antibody toBordetella pertussisAdenylate Cyclase Toxin in Vaccinated and Unvaccinated Children and in Children and Adults with Pertussis. Clin Infect Dis 2004; 38:502-7. [PMID: 14765342 DOI: 10.1086/381204] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 10/07/2003] [Indexed: 11/03/2022] Open
Abstract
Presence of antibody to adenylate cyclase toxin (ACT) has been noted following Bordetella pertussis infection. Because ACT is not presently in any acellular pertussis vaccines, it has been considered as a possible antigen to use in B. pertussis diagnostic enzyme-linked immunosorbent assay (ELISA) studies. We determined antibody to B. pertussis ACT by ELISA and Western blot tests in serum samples obtained from unvaccinated children, from children vaccinated with several diphtheria and tetanus toxoid vaccines (DTP vaccines), from children vaccinated with vaccines containing acellular pertussis components in combination with diphtheria and tetanus toxoids (DTaP vaccines), and from children and adults with pertussis. Primary infections with either B. pertussis or Bordetella parapertussis stimulated a vigorous antibody response to ACT. In contrast, patients in whom DTP and DTaP vaccines failed had minimal ACT antibody responses. The lack of a significant ACT antibody response in children in whom the vaccine failed is of interest but would seem to preclude the use of ACT in diagnostic tests.
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Affiliation(s)
- James D Cherry
- Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA.
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47
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Mašín J, Konopásek I, Svobodová J, Šebo P. Different structural requirements for adenylate cyclase toxin interactions with erythrocyte and liposome membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004. [DOI: 10.1016/j.bbamem.2003.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zaretzky FR, Gray MC, Hewlett EL. Mechanism of association of adenylate cyclase toxin with the surface of Bordetella pertussis: a role for toxin-filamentous haemagglutinin interaction. Mol Microbiol 2002; 45:1589-98. [PMID: 12354227 DOI: 10.1046/j.1365-2958.2002.03107.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Adenylate cyclase (AC) toxin from Bordetella pertussis is unusual in that, unlike most other members of the repeats-in-toxin family that are released into the extracellular milieu, it remains associated with the bacterial surface. In this study, we investigated the nature of the association of this toxin with the surface of B. pertussis. AC toxin was extracted from crude outer membrane preparations of B. pertussis with 8 M urea, but only partially with alkaline sodium carbonate and not at all with octylglucoside, suggesting that denaturation of the toxin is necessary for its removal from the membrane. B. pertussis mutants lacking filamentous haemagglutinin (FHA) released significantly more AC toxin into the medium, and AC toxin association with the bacterial surface was partially restored by expression of FHA from a plasmid, suggesting a role for FHA in surface retention of AC toxin. AC toxin distribution was unaffected by the absence of pertactin, or full-length lipopolysaccharide, or a defect in secretion of pertussis toxin. Using overlay and immunoprecipitation, we found that a direct physical association can occur between AC toxin and FHA. Combined, these findings suggest that FHA may play a role in AC toxin retention on the surface of B. pertussis and raise the possibility of an involvement of adherence mediated by FHA in delivery of AC toxin from the bacterium to the target cell.
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Affiliation(s)
- Franca R Zaretzky
- University of Virginia School of Medicine, Department of Internal Medicine, Charlottesville, Virginia 22908, USA
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Rhodes CR, Gray MC, Watson JM, Muratore TL, Kim SB, Hewlett EL, Grisham CM. Structural consequences of divalent metal binding by the adenylyl cyclase toxin of Bordetella pertussis. Arch Biochem Biophys 2001; 395:169-76. [PMID: 11697853 DOI: 10.1006/abbi.2001.2553] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenylyl cyclase toxin of Bordetella pertussis has been shown by several investigators to require Ca(2+) for its actions on target cells, but little is known about the nature and specificity of divalent metal binding to this novel toxin. Calcium is the preferred divalent metal since toxic actions are markedly reduced in the presence of divalent species other than calcium. Mn(2+) EPR was used to quantitate and characterize divalent metal binding and revealed that the toxin contains approximately 40 divalent metal sites, consisting of at least one class of high-affinity sites that bind Mn(2+) with a K(D) of 0.05 to 0.35 microM and one or more classes of lower affinity sites. Water proton relaxation data indicate that approximately 30 of these sites are completely inaccessible to bulk solvent. Our observations, together with the sequence homology between adenylyl cyclase toxin and the alkaline protease of Pseudomonas aeruginosa, indicate that the formation of five beta-sheet helices within the repeat domain of the toxin upon binding Ca(2+) is required for cell intoxication.
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Affiliation(s)
- C R Rhodes
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22906, USA
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50
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Gray MC, Lee SJ, Gray LS, Zaretzky FR, Otero AS, Szabo G, Hewlett EL. Translocation-specific conformation of adenylate cyclase toxin from Bordetella pertussis inhibits toxin-mediated hemolysis. J Bacteriol 2001; 183:5904-10. [PMID: 11566989 PMCID: PMC99668 DOI: 10.1128/jb.183.20.5904-5910.2001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bordetella pertussis adenylate cyclase (AC) toxin belongs to the RTX family of toxins but is the only member with a known catalytic domain. The principal pathophysiologic function of AC toxin appears to be rapid production of intracellular cyclic AMP (cAMP) by insertion of its catalytic domain into target cells (referred to as intoxication). Relative to other RTX toxins, AC toxin is weakly hemolytic via a process thought to involve oligomerization of toxin molecules. Monoclonal antibody (MAb) 3D1, which binds to an epitope (amino acids 373 to 399) at the distal end of the catalytic domain of AC toxin, does not affect the enzymatic activity of the toxin (conversion of ATP into cAMP in a cell-free system) but does prevent delivery of the catalytic domain to the cytosol of target erythrocytes. Under these conditions, however, the ability of AC toxin to cause hemolysis is increased three- to fourfold. To determine the mechanism by which the hemolytic potency of AC toxin is altered, we used a series of deletion mutants. A mutant toxin, DeltaAC, missing amino acids 1 to 373 of the catalytic domain, has hemolytic activity comparable to that of wild-type toxin. However, binding of MAb 3D1 to DeltaAC enhances its hemolytic activity three- to fourfold similar to the enhancement of hemolysis observed with 3D1 addition to wild-type toxin. Two additional mutants, DeltaN489 (missing amino acids 6 to 489) and DeltaN518 (missing amino acids 6 to 518), exhibit more rapid hemolysis with quicker onset than wild-type toxin does, while DeltaN549 (missing amino acids 6 to 549) has reduced hemolytic activity compared to wild-type AC toxin. These data suggest that prevention of delivery of the catalytic domain or deletion of the catalytic domain, along with additional amino acids distal to it, elicits a conformation of the toxin molecule that is more favorable for hemolysis.
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Affiliation(s)
- M C Gray
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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