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Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication

The AB-type protein toxin from Pasteurella multocida (PMT) contains a functionally important disulfide bond within its catalytic domain, which must be cleaved in the host cell cytosol to render the catalytic domain of PMT into its active conformation. Here, we found that the reductive potential of t...

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Autores principales: Carle, Stefan, Brink, Thorsten, Orth, Joachim H. C., Aktories, Klaus, Barth, Holger
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5308264/
https://www.ncbi.nlm.nih.gov/pubmed/28098782
http://dx.doi.org/10.3390/toxins9010032
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author Carle, Stefan
Brink, Thorsten
Orth, Joachim H. C.
Aktories, Klaus
Barth, Holger
author_facet Carle, Stefan
Brink, Thorsten
Orth, Joachim H. C.
Aktories, Klaus
Barth, Holger
author_sort Carle, Stefan
collection PubMed
description The AB-type protein toxin from Pasteurella multocida (PMT) contains a functionally important disulfide bond within its catalytic domain, which must be cleaved in the host cell cytosol to render the catalytic domain of PMT into its active conformation. Here, we found that the reductive potential of the cytosol of target cells, and more specifically, the activity of the thioredoxin reductase (TrxR) is crucial for this process. This was demonstrated by the strong inhibitory effect of the pharmacological TrxR inhibitor auranofin, which inhibited the intoxication of target cells with PMT, as determined by analyzing the PMT-catalyzed deamidation of GTP-binding proteins (G-proteins) in the cytosol of cells. The amount of endogenous substrate levels modified by PMT in cells pretreated with auranofin was reduced compared to cells treated with PMT alone. Auranofin had no inhibitory effect on the activity of the catalytic domain of constitutively active PMT in vitro, demonstrating that auranofin did not directly inhibit PMT activity, but interferes with the mode of action of PMT in cells. In conclusion, the results show that TrxR is crucial for the mode of action of PMT in mammalian cells, and that the drug auranofin can serve as an efficient inhibitor, which might be a starting point for novel therapeutic options against toxin-associated diseases.
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spelling pubmed-53082642017-02-14 Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication Carle, Stefan Brink, Thorsten Orth, Joachim H. C. Aktories, Klaus Barth, Holger Toxins (Basel) Article The AB-type protein toxin from Pasteurella multocida (PMT) contains a functionally important disulfide bond within its catalytic domain, which must be cleaved in the host cell cytosol to render the catalytic domain of PMT into its active conformation. Here, we found that the reductive potential of the cytosol of target cells, and more specifically, the activity of the thioredoxin reductase (TrxR) is crucial for this process. This was demonstrated by the strong inhibitory effect of the pharmacological TrxR inhibitor auranofin, which inhibited the intoxication of target cells with PMT, as determined by analyzing the PMT-catalyzed deamidation of GTP-binding proteins (G-proteins) in the cytosol of cells. The amount of endogenous substrate levels modified by PMT in cells pretreated with auranofin was reduced compared to cells treated with PMT alone. Auranofin had no inhibitory effect on the activity of the catalytic domain of constitutively active PMT in vitro, demonstrating that auranofin did not directly inhibit PMT activity, but interferes with the mode of action of PMT in cells. In conclusion, the results show that TrxR is crucial for the mode of action of PMT in mammalian cells, and that the drug auranofin can serve as an efficient inhibitor, which might be a starting point for novel therapeutic options against toxin-associated diseases. MDPI 2017-01-13 /pmc/articles/PMC5308264/ /pubmed/28098782 http://dx.doi.org/10.3390/toxins9010032 Text en © 2017 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Carle, Stefan
Brink, Thorsten
Orth, Joachim H. C.
Aktories, Klaus
Barth, Holger
Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title_full Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title_fullStr Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title_full_unstemmed Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title_short Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication
title_sort auranofin inhibits the enzyme activity of pasteurella multocida toxin pmt in human cells and protects cells from intoxication
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5308264/
https://www.ncbi.nlm.nih.gov/pubmed/28098782
http://dx.doi.org/10.3390/toxins9010032
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