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Pons BJ, Loiseau N, Hashim S, Tadrist S, Mirey G, Vignard J. Functional Study of Haemophilus ducreyi Cytolethal Distending Toxin Subunit B. Toxins (Basel) 2020; 12:toxins12090530. [PMID: 32825080 PMCID: PMC7551728 DOI: 10.3390/toxins12090530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
The Cytolethal Distending Toxin (CDT) is produced by many Gram-negative pathogenic bacteria responsible for major foodborne diseases worldwide. CDT induces DNA damage and cell cycle arrest in host-cells, eventually leading to senescence or apoptosis. According to structural and sequence comparison, the catalytic subunit CdtB is suggested to possess both nuclease and phosphatase activities, carried by a single catalytic site. However, the impact of each activity on cell-host toxicity is yet to be characterized. Here, we analyze the consequences of cell exposure to different CDT mutated on key CdtB residues, focusing on cell viability, cell cycle defects, and DNA damage induction. A first class of mutant, devoid of any activity, targets putative catalytic (H160A), metal binding (D273R), and DNA binding residues (R117A-R144A-N201A). The second class of mutants (A163R, F156-T158, and the newly identified G114T), which gathers mutations on residues potentially involved in lipid substrate binding, has only partially lost its toxic effects. However, their defects are alleviated when CdtB is artificially introduced inside cells, except for the F156-T158 double mutant that is defective in nuclear addressing. Therefore, our data reveal that CDT toxicity is mainly correlated to CdtB nuclease activity, whereas phosphatase activity may probably be involved in CdtB intracellular trafficking.
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Affiliation(s)
| | | | | | | | - Gladys Mirey
- Correspondence: (G.M.); (J.V.); Tel.: +33-582-066-338 (G.M.)
| | - Julien Vignard
- Correspondence: (G.M.); (J.V.); Tel.: +33-582-066-338 (G.M.)
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Varon C, Mocan I, Mihi B, Péré-Védrenne C, Aboubacar A, Moraté C, Oleastro M, Doignon F, Laharie D, Mégraud F, Ménard A. Helicobacter pullorum Cytolethal Distending Toxin Targets Vinculin and Cortactin and Triggers Formation of Lamellipodia in Intestinal Epithelial Cells. J Infect Dis 2014; 209:588-99. [DOI: 10.1093/infdis/jit539] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Li L, Ding C, Duan JL, Yang MF, Sun Y, Wang XQ, Xu Y. A new functional site W115 in CdtA is critical for Aggregatibacter actinomycetemcomitans cytolethal distending toxin. PLoS One 2013; 8:e65729. [PMID: 23755273 PMCID: PMC3670888 DOI: 10.1371/journal.pone.0065729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 05/03/2013] [Indexed: 11/18/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans, a specific pathogen of localized aggressive periodontitis, produces a cytolethal distending toxin (CDT) that arrests eukaryotic cells irreversibly in G0/G1 or G2/M phase of the cell cycle. Although structural studies show that the aromatic patch region of CdtA plays an important role in its biological activity, the functional sites of CdtA have not been firmly established. In this study, site-specific mutagenesis strategy was employed for cdtA point mutations construction so as to examine the contributions of individual amino acids to receptor binding and the biological activity of holotoxin. The binding ability was reduced in CdtAY181ABC holotoxin and the biological function of CDT was not weaken in CdtAY105ABC, CdtAY125ABC, CdtAF109ABC and CdtAS106NBC holotoxin suggesting that these sites were not critical to CDT. But the binding activity and cell cycle arrest ability of holotoxin complexes were inhibited in CdtAW115GBC. And this site did not affect the holotoxin assembly by size exclusion chromatography. Therefore, W115 might be a critical site of CdtA binding ability. These findings suggest that the functional sites of CdtA are not only in the aromatic patch region. W115, the new functional site is critical for receptor binding and cell cycle arrest, which provides potential targets for pharmacological disruption of CDT activity.
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Affiliation(s)
- Lu Li
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
| | - Cheng Ding
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
| | - Jun-lan Duan
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
| | - Mi-fang Yang
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
| | - Ying Sun
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
| | - Xiao-qian Wang
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
| | - Yan Xu
- Laboratory of Oral Infection and Immunology, Institute of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Periodontology, School of Stomatology, Nanjing Medical University, Nanjing, China
- * E-mail:
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Gargi A, Tamilselvam B, Powers B, Prouty MG, Lincecum T, Eshraghi A, Maldonado-Arocho FJ, Wilson BA, Bradley KA, Blanke SR. Cellular interactions of the cytolethal distending toxins from Escherichia coli and Haemophilus ducreyi. J Biol Chem 2013; 288:7492-7505. [PMID: 23306199 DOI: 10.1074/jbc.m112.448118] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The cytolethal distending toxins (CDTs) compose a subclass of intracellularly acting genotoxins produced by many Gram-negative pathogenic bacteria that disrupt the normal progression of the eukaryotic cell cycle. Here, the intoxication mechanisms of CDTs from Escherichia coli (Ec-CDT) and Haemophilus ducreyi (Hd-CDT), which share limited amino acid sequence homology, were directly compared. Ec-CDT and Hd-CDT shared comparable in vitro DNase activities of the CdtB subunits, saturable cell surface binding with comparable affinities, and the requirement for an intact Golgi complex to induce cell cycle arrest. In contrast, disruption of endosome acidification blocked Hd-CDT-mediated cell cycle arrest and toxin transport to the endoplasmic reticulum and nucleus, while having no effects on Ec-CDT. Phosphorylation of the histone protein H2AX, as well as nuclear localization, was inhibited for Hd-CdtB, but not Ec-CdtB, in cells expressing dominant negative Rab7 (T22N), suggesting that Hd-CDT, but not Ec-CDT, is trafficked through late endosomal vesicles. In support of this idea, significantly more Hd-CdtB than Ec-CdtB co-localized with Rab9, which is enriched in late endosomal compartments. Competitive binding studies suggested that Ec-CDT and Hd-CDT bind to discrete cell surface determinants. These results suggest that Ec-CDT and Hd-CDT are transported within cells by distinct pathways, possibly mediated by their interaction with different receptors at the cell surface.
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Affiliation(s)
- Amandeep Gargi
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801
| | - Batcha Tamilselvam
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801
| | - Brendan Powers
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801
| | - Michael G Prouty
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801
| | - Tommie Lincecum
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204
| | - Aria Eshraghi
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, California 90095
| | | | - Brenda A Wilson
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801; Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - Kenneth A Bradley
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, California 90095
| | - Steven R Blanke
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801; Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801.
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