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Special Issue "Pore-Forming Toxins (PFTs): Never Out of Fashion"

A special issue of Toxins (ISSN 2072-6651).

Deadline for manuscript submissions: closed (31 May 2019)

Special Issue Editors

Guest Editor
Prof. Dr. Alvaro Martínez-del-Pozo

Departamento de Bioquímica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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Phone: 34 91 394 4259
Guest Editor
Dr. Sara García Linares

Cell Biology Department, Harvard Medical School, Boston, MA 02115, USA
E-Mail

Special Issue Information

Dear Colleagues,

Pore-forming toxins (PFTs) are ubiquitous peptides and proteins present in a wide variety of organisms, from prokaryotes to multicellular eukaryotes. Given their toxic character, they abound in venoms. Usually produced as water-soluble components, they suffer different conformational and oligomerization arrangements to become integral membrane structures, forming a pore. Typically, this pore leads to the death of the target cell by osmotic shock. Although most of them share a general mode of action, there is still much to learn about the particulars of their mechanism. Some PFTs recognize specific protein membrane receptors to achieve their action, but many others take advantage of the different membrane composition among organisms and/or cellular organelles. Accordingly, in many instances, PFTs target specific lipids such as sphingomyelin or cholesterol. Overall, further understanding PFTs molecular mechanisms will expand the available repertoire of pharmacological and biotechnological tools and will help to improve our knowledge of venoms composition and envenomation.

Prof. Dr. Alvaro Martínez-del-Pozo
Dr. Sara García Linares
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Venom
  • Toxin
  • Pore
  • Ion channel
  • Lipid rafts
  • Cholesterol
  • Sphingomyelin
  • Oligomerization
  • Membrane-protein interactions

Published Papers (2 papers)

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Research

Open AccessArticle
Binding to The Target Cell Surface Is The Crucial Step in Pore Formation of Hemolysin BL from Bacillus cereus
Received: 18 April 2019 / Revised: 13 May 2019 / Accepted: 16 May 2019 / Published: 20 May 2019
PDF Full-text (3084 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A major virulence factor involved in Bacillus cereus food poisoning is the three-component enterotoxin hemolysin BL. It consists of the binding component B and the two lytic components L1 and L2. Studying its mode of action has been challenging, as [...] Read more.
A major virulence factor involved in Bacillus cereus food poisoning is the three-component enterotoxin hemolysin BL. It consists of the binding component B and the two lytic components L1 and L2. Studying its mode of action has been challenging, as natural culture supernatants additionally contain Nhe, the second three-component enterotoxin, and purification of recombinant (r) Hbl components has been difficult. In this study, we report on pore-forming, cytotoxic, cell binding and hemolytic activity of recently generated rHbl components expressed in E. coli. It is known that all three Hbl components are necessary for cytotoxicity and pore formation. Here we show that an excess of rHbl B enhances, while an excess of rHbl L1 hinders, the velocity of pore formation. Most rapid pore formation was observed with ratios L2:L1:B = 1:1:10 and 10:1:10. It was further verified that Hbl activity is due to sequential binding of the components B - L1 - L2. Accordingly, all bioassays proved that binding of Hbl B to the cell surface is the crucial step for pore formation and cytotoxic activity. Binding of Hbl B took place within minutes, while apposition of the following L1 and L2 occurred immediately. Further on, applying toxin components simultaneously, it seemed that Hbl L1 enhanced binding of B to the target cell surface. Overall, these data contribute significantly to the elucidation of the mode of action of Hbl, and suggest that its mechanism of pore formation differs substantially from that of Nhe, although both enterotoxin complexes are sequentially highly related. Full article
(This article belongs to the Special Issue Pore-Forming Toxins (PFTs): Never Out of Fashion)
Figures

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Open AccessArticle
Structural Insights to the Heterotetrameric Interaction between the Vibrio parahaemolyticus PirAvp and PirBvp Toxins and Activation of the Cry-Like Pore-Forming Domain
Received: 26 March 2019 / Revised: 16 April 2019 / Accepted: 19 April 2019 / Published: 22 April 2019
PDF Full-text (5100 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Acute hepatopancreatic necrosis disease (AHPND) is a newly emergent penaeid shrimp disease which can cause 70–100% mortality in Penaeus vannamei and Penaeus monodon, and has resulted in enormous economic losses since its appearance. AHPND is caused by the specific strains of Vibrio [...] Read more.
Acute hepatopancreatic necrosis disease (AHPND) is a newly emergent penaeid shrimp disease which can cause 70–100% mortality in Penaeus vannamei and Penaeus monodon, and has resulted in enormous economic losses since its appearance. AHPND is caused by the specific strains of Vibrio parahaemolyticus that harbor the pVA1 plasmid and express PirAvp and PirBvp toxins. These two toxins have been reported to form a binary complex. When both are present, they lead to the death of shrimp epithelial cells in the hepatopancreas and cause the typical histological symptoms of AHPND. However, the binding mode of PirAvp and PirBvp has not yet been determined. Here, we used isothermal titration calorimetry (ITC) to measure the binding affinity of PirAvp and PirBvp. Since the dissociation constant (Kd = 7.33 ± 1.20 μM) was considered too low to form a sufficiently stable complex for X-ray crystallographic analysis, we used alternative methods to investigate PirAvp-PirBvp interaction, first by using gel filtration to evaluate the molecular weight of the PirAvp/PirBvp complex, and then by using cross-linking and hydrogen-deuterium exchange (HDX) mass spectrometry to further understand the interaction interface between PirAvp and PirBvp. Based on these results, we propose a heterotetrameric interaction model of this binary toxin complex. This model provides insight of how conformational changes might activate the PirBvp N-terminal pore-forming domain and should be helpful for devising effective anti-AHPND strategies in the future. Full article
(This article belongs to the Special Issue Pore-Forming Toxins (PFTs): Never Out of Fashion)
Figures

Figure 1

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