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Song H, Zhang W. Cloning and characterization of an aerolysin gene from a marine pathogen Vibrio splendidus. Microb Pathog 2024; 187:106519. [PMID: 38158142 DOI: 10.1016/j.micpath.2023.106519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/06/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Vibrio splendidus is one of the main pathogens caused diseases with a diversity of marine cultured animals, especially the skin ulcer syndrome in Apostichopus japonicus. However, limited virulence factors have been identified in V. splendidus. In this study, one aerAVs gene coding an aerolysin of V. splendidus was cloned and conditionally expressed in Escherichia coli. The haemolytic activity of the recombinant AerAVs was analyzed. Western blotting was used to study of the secretion pathway of proaerolysin, and it showed that the proaerolysin was secreted via both outer membrane vehicles and classical secretion pathways. Since no active protein of aerolysin was obtained, one aerolysin surface displayed bacterium DH5α/pAT-aerA was constructed, and its haemolytic activity and virulence were determined. The results showed that the AerAVs displayed on the surface showed obvious haemolytic activity and cytotoxic to the coelomocyte of A. japonicus. Artificial immerse infection separately using the DH5α/pAT or DH5α/pAT-aerA was conducted. The result showed that the mortality percent of sea cucumber A. japonicus challenged with DH5α/pAT-aerA was 38.89 % higher than that challenged with the control strain DH5α/pAT, and earlier death occurred. Combined all the results indicates that aerolysin with the haemolytic activity and cytotoxic activity is a virulence factor of V. splendidus.
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Affiliation(s)
- Huimin Song
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315832, PR China; School of Marine Sciences, Ningbo University, Ningbo, PR China
| | - Weiwei Zhang
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315832, PR China; School of Marine Sciences, Ningbo University, Ningbo, PR China.
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Patel TR, Winzor DJ, Scott DJ. Analytical ultracentrifugation: A versatile tool for the characterisation of macromolecular complexes in solution. Methods 2016; 95:55-61. [DOI: 10.1016/j.ymeth.2015.11.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/05/2015] [Accepted: 11/07/2015] [Indexed: 12/25/2022] Open
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Wuethrich I, Peeters JGC, Blom AEM, Theile CS, Li Z, Spooner E, Ploegh HL, Guimaraes CP. Site-specific chemoenzymatic labeling of aerolysin enables the identification of new aerolysin receptors. PLoS One 2014; 9:e109883. [PMID: 25275512 PMCID: PMC4183550 DOI: 10.1371/journal.pone.0109883] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 09/04/2014] [Indexed: 11/29/2022] Open
Abstract
Aerolysin is a secreted bacterial toxin that perforates the plasma membrane of a target cell with lethal consequences. Previously explored native and epitope-tagged forms of the toxin do not allow site-specific modification of the mature toxin with a probe of choice. We explore sortase-mediated transpeptidation reactions (sortagging) to install fluorophores and biotin at three distinct sites in aerolysin, without impairing binding of the toxin to the cell membrane and with minimal impact on toxicity. Using a version of aerolysin labeled with different fluorophores at two distinct sites we followed the fate of the C-terminal peptide independently from the N-terminal part of the toxin, and show its loss in the course of intoxication. Making use of the biotinylated version of aerolysin, we identify mesothelin, urokinase plasminogen activator surface receptor (uPAR, CD87), glypican-1, and CD59 glycoprotein as aerolysin receptors, all predicted or known to be modified with a glycosylphosphatidylinositol anchor. The sortase-mediated reactions reported here can be readily extended to other pore forming proteins.
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Affiliation(s)
- Irene Wuethrich
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Janneke G. C. Peeters
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Annet E. M. Blom
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Christopher S. Theile
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Zeyang Li
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Eric Spooner
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Hidde L. Ploegh
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
| | - Carla P. Guimaraes
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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Iacovache I, van der Goot FG, Pernot L. Pore formation: an ancient yet complex form of attack. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1611-23. [PMID: 18298943 DOI: 10.1016/j.bbamem.2008.01.026] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 01/03/2008] [Accepted: 01/04/2008] [Indexed: 02/07/2023]
Abstract
Bacteria, as well as higher organisms such as sea anemones or earthworms, have developed sophisticated virulence factors such as the pore-forming toxins (PFTs) to mount their attack against the host. One of the most fascinating aspects of PFTs is that they can adopt a water-soluble form at the beginning of their lifetime and become an integral transmembrane protein in the membrane of the target cells. There is a growing understanding of the sequence of events and the various conformational changes undergone by these toxins in order to bind to the host cell surface, to penetrate the cell membranes and to achieve pore formation. These points will be addressed in this review.
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Affiliation(s)
- Ioan Iacovache
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Faculty of Life Sciences, Station 15, Lausanne, Switzerland
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Gilbert RJC. Inactivation and Activity of Cholesterol-Dependent Cytolysins: What Structural Studies Tell Us. Structure 2005; 13:1097-106. [PMID: 16084382 DOI: 10.1016/j.str.2005.04.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2005] [Revised: 04/21/2005] [Accepted: 04/26/2005] [Indexed: 10/25/2022]
Abstract
The homologous bacterially expressed cholesterol-dependent cytolysins (CDCs) form pores via oligomerization; this must occur preferentially once the target membrane has been engaged. Conformational changes in CDCs then drive partition from an aqueous environment to a lipidic one. This review addresses how premature oligomerization is prevented, how conformational changes are triggered, and how cooperativity between subunits brings about new functionality absent from isolated protomers. Variations are found in the answers provided by the CDCs to these issues. Some toxins use pH as a trigger of activity, but recent results have shown that dimerization in solution is an alternative way of preventing premature oligomerization, in particular for the CDC from Clostridium perfringens, perfringolysin. More controversially, there is still no resolution to the debate as to whether incomplete (arciform) oligomers form pores: recent results again suggest that they do.
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Affiliation(s)
- Robert J C Gilbert
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, United Kingdom.
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Parker MW, Feil SC. Pore-forming protein toxins: from structure to function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 88:91-142. [PMID: 15561302 DOI: 10.1016/j.pbiomolbio.2004.01.009] [Citation(s) in RCA: 339] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pore-forming protein toxins (PFTs) are one of Nature's most potent biological weapons. An essential feature of their toxicity is the remarkable property that PFTs can exist either in a stable water-soluble state or as an integral membrane pore. In order to convert from the water-soluble to the membrane state, the toxin must undergo large conformational changes. There are now more than a dozen PFTs for which crystal structures have been determined and the nature of the conformational changes they must undergo is beginning to be understood. Although they differ markedly in their primary, secondary, tertiary and quaternary structures, nearly all can be classified into one of two families based on the types of pores they are thought to form: alpha-PFTs or beta-PFTs. Recent work suggests a number of common features in the mechanism of membrane insertion may exist for each class.
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Affiliation(s)
- Michael W Parker
- Biota Structural Biology Laboratory, St. Vincent's Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia.
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Dong F, Sharma J, Xiao Y, Zhong Y, Zhong G. Intramolecular dimerization is required for the chlamydia-secreted protease CPAF to degrade host transcriptional factors. Infect Immun 2004; 72:3869-75. [PMID: 15213129 PMCID: PMC427400 DOI: 10.1128/iai.72.7.3869-3875.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously identified a chlamydial protein designated CPAF (chlamydia protease/proteasome-like activity factor) that is secreted into host cell cytosol for degrading host transcription factors required for major histocompatibility complex antigen expression. Here we report that CPAF, synthesized as a 70-kDa proprotein, is processed into two fragments (designated CPAFn and CPAFc) to form intramolecular dimers that are much more stable than the naïve CPAF. Precipitation with antibodies that recognized CPAF dimers removed the proteolytic activity responsible for degrading host transcription factor RFX5 from chlamydia-infected host cell cytosol, while precipitation with antibodies that recognized free CPAF fragments alone did not remove this activity. Separation of CPAFn from CPAFc resulted in a loss of proteolytic activity. Furthermore, neither expressed full-length CPAF that was not processed nor coexpressed CPAFn and CPAFc fragments that failed to form dimers degraded RFX5. These observations demonstrate that intramolecular dimerization is required for CPAF to degrade host transcription factors, a strategy that is utilized by an obligate intracellular bacterial species to evade host defenses.
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Affiliation(s)
- Feng Dong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Abstract
A chlamydia-secreted protein designated CPAF (chlamydial proteasome-like activity factor) was shown previously to degrade host transcriptional factors (e.g. RFX5) required for major histocompatibility (MHC) gene activation. Although CPAF is encoded by a single open reading frame (ORF) in the chlamydial genome, two fragments designated CPAFn and CPAFc were the main products purified. The current study was designed to test whether cleavage of CPAF into CPAFn and CPAFc is a physiological process required for CPAF proteolytic activity. Pulse-chase experiments revealed that CPAF was initially synthesized in chlamydia-infected cells as a 70 kDa full-length protein and rapidly cleaved into CPAFn and c fragments. Full-length CPAF expressed via a transgene in mammalian cells remained uncleaved and had no proteolytic activity, whereas CPAF expressed in Escherichia coli cells was processed and possessed RFX5 degradation activity. CPAF mutants deficient in processing even when expressed by E. coli failed to degrade RFX5. More importantly, the RFX5 degradation activity was partially restored when the mutant CPAF was artificially induced to undergo cleavage. These observations together have demonstrated that cleavage of CPAF is both necessary and sufficient for CPAF activity.
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Affiliation(s)
- Feng Dong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Valeva A, Walev I, Weis S, Boukhallouk F, Wassenaar TM, Endres K, Fahrenholz F, Bhakdi S, Zitzer A. A cellular metalloproteinase activates Vibrio cholerae pro-cytolysin. J Biol Chem 2004; 279:25143-8. [PMID: 15066987 DOI: 10.1074/jbc.m313913200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many strains of Vibrio cholerae produce a cytolysin (VCC) that forms oligomeric transmembrane pores in animal cells. The molecule is secreted as a procytolysin (pro-VCC) of 79 kDa that must be cleaved at the N terminus to generate the active 65-kDa toxin. Processing can occur in solution, and previous studies have described the action of mature VCC thus generated. However, little is known about the properties of pro-VCC itself. In this study, it is shown that pro-VCC exist as a monomer in solution and binds as a monomer to eukaryotic cells. Bound pro-VCC can then be activated either by exogenous, extracellular, or by endogenous, cell-bound proteases. In both cases, cleavage generates the 65-kDa VCC that oligomerizes to form transmembrane pores. A wide variety of exogenous proteinases can mediate activation. In contrast, the activating cellular protease is selectively inhibited by the hydroxamate inhibitor TAPI, and thus probable candidates are members of the ADAM-metalloproteinase family. Furin, MMP-2, MMP-9, and serine proteinases were excluded. Cells over-expressing ADAM-17, also known as tumor necrosis factor alpha converting enzyme, displayed increased activation of VCC, and knockout cells lacking ADAM-17 had a markedly decreased capacity to cleave the protoxin. The possibility is raised that pro-VCC is targeted to membrane sites that selectively contain or are accessible to cellular ADAM-metalloproteinases. Although many microbial toxins are activated by furin, this is the first evidence for processing by a cellular metalloproteinase. We identified ADAM-17 as a potent activator of pro-VCC.
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Affiliation(s)
- Angela Valeva
- Institute of Medical Microbiology and Hygiene, University of Mainz, D55101 Mainz, Germany.
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Melton JA, Parker MW, Rossjohn J, Buckley JT, Tweten RK. The Identification and Structure of the Membrane-spanning Domain of the Clostridium septicum Alpha Toxin. J Biol Chem 2004; 279:14315-22. [PMID: 14715670 DOI: 10.1074/jbc.m313758200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alpha toxin (AT) is a pore-forming toxin produced by Clostridium septicum that belongs to the unique aerolysin-like family of pore-forming toxins. The location and structure of the transmembrane domains of these toxins have remained elusive. Using deletion mutagenesis, cysteine-scanning mutagenesis and multiple spectrofluorimetric methods a membrane-spanning amphipathic beta-hairpin of AT has been identified. Spectrofluorimetric analysis of cysteine-substituted residues modified with an environmentally sensitive fluorescent probe via the cysteine sulfydryl showed that the side chains of residues 203-232 alternated between the aqueous milieu and the membrane core when the AT oligomer was inserted into membranes, consistent with the formation of an amphipathic transmembrane beta-hairpin. AT derivatives that contained deletions that removed up to 90% of the beta-hairpin did not form a pore but were similar to native toxin in all other aspects of the mechanism. Furthermore, a mutant of AT that contained an engineered disulfide, predicted to restrict the movement of the beta-hairpin, functioned similarly to native toxin except that it did not form a pore unless the disulfide bond was reduced. Together these studies revealed the location and structure of the membrane-spanning domain of AT.
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Affiliation(s)
- Jody A Melton
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA
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Wadehra M, Goodglick L, Braun J. The tetraspan protein EMP2 modulates the surface expression of caveolins and glycosylphosphatidyl inositol-linked proteins. Mol Biol Cell 2004; 15:2073-83. [PMID: 14978215 PMCID: PMC404005 DOI: 10.1091/mbc.e03-07-0488] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Caveolae are a subset of lipid rafts enriched in glycosphingolipids and cholesterol-rich domains, but selectively lacking glycosylphosphatidyl inositol-anchored proteins (GPI-APs). Caveolin proteins are the organizing component of caveolae, but the corresponding proteins for other classes of lipid rafts are poorly defined. Epithelial membrane protein-2 (EMP2), a member of the four-transmembrane superfamily, facilitates plasma membrane delivery of certain integrins. In this study, we found by laser confocal microscopy that EMP2 was associated with GPI-APs (detected by the GPI-AP binding bacterial toxin proaerolysin). Biochemical membrane fractionation and methyl-beta-cyclodextrin treatment demonstrated that this association occurred within lipid rafts. EMP2 did not associate with caveolin-bearing membrane structures, and recombinant overexpression of EMP2 in NIH3T3 cells decreased caveolin-1 and caveolin-2 protein levels while increasing the surface expression of GPI-APs. Conversely, a ribozyme construct that specifically cleaves the EMP2 transcript reduced surface GPI-APs and increased caveolin protein expression. These findings suggest that EMP2 facilitates the formation and surface trafficking of lipid rafts bearing GPI-APs, and reduces caveolin expression, resulting in impaired formation of caveolae.
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Affiliation(s)
- Madhuri Wadehra
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
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Bittencourt SET, Silva LP, Azevedo RB, Cunha RB, Lima CMR, Ricart CAO, Sousa MV. The plant cytolytic protein enterolobin assumes a dimeric structure in solution. FEBS Lett 2003; 549:47-51. [PMID: 12914923 DOI: 10.1016/s0014-5793(03)00763-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Enterolobin is a plant cytolytic protein similar to the bacterial cytolysin aerolysin. Biochemical and biophysical techniques were used to verify if enterolobin, like aerolysin, adopts a dimeric structure in solution. SDS-PAGE showed bands corresponding to enterolobin monomer, dimer and oligomers, whilst gel filtration chromatography and electrospray mass spectrometry revealed preferred association of enterolobin as a dimer. Atomic force microscopy (AFM) of enterolobin showed images of a dimer assembly at a concentration as low as 10 microg/ml, similarly to aerolysin. The enterolobin in silico docked structure is coherent with AFM enterolobin dimer shapes.
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Affiliation(s)
- Silvia E T Bittencourt
- Brazilian Center for Protein Research, Department of Cell Biology, University of Brasília, 70910-900, Brasília, Brazil
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Abstract
Like a variety of other pathogenic bacteria, Aeromonas hydrophila secretes a pore-forming toxin that contribute to its virulence. The last decade has not only increased our knowledge about the structure of this toxin, called aerolysin, but has also shed light on how it interacts with its target cell and how the cell reacts to this stress. Whereas pore-forming toxins are generally thought to lead to brutal death by osmotic lysis of the cell, based on what is observed for erythrocytes, recent studies have started to reveal far more complicated pathways leading to death of nucleated mammalian cells.
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Affiliation(s)
- M Fivaz
- Department of Biochemistry, Faculty of Sciences, University of Geneva, 30 quai E. Ansermet, 1211 Geneva 4, Switzerland
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