<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells

ABSTRACT Clostridium sordellii infections cause gangrene and edema in humans and gastrointestinal infections in livestock. One of the principle virulence factors is TcsL, a large protein toxin which glucosylates host GTPases to cause cytopathic and cytotoxic effects. TcsL has two enzymatic domains,...

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Autores principales:	Ryan Craven, D. Borden Lacy
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2016
Materias:	cytotoxins membranes glucosylation GTPases Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/55346b51151e48caaabab25e992876e8
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spelling	oai:doaj.org-article:55346b51151e48caaabab25e992876e82021-11-15T15:21:38Z<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells10.1128/mSphere.00012-152379-5042https://doaj.org/article/55346b51151e48caaabab25e992876e82016-02-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00012-15https://doaj.org/toc/2379-5042ABSTRACT Clostridium sordellii infections cause gangrene and edema in humans and gastrointestinal infections in livestock. One of the principle virulence factors is TcsL, a large protein toxin which glucosylates host GTPases to cause cytopathic and cytotoxic effects. TcsL has two enzymatic domains, an N-terminal glucosyltransferase domain (GTD) and an autoprocessing domain responsible for release of the GTD within the cell. The GTD can then use its N-terminal membrane localization domain (MLD) for orientation on membranes and modification of GTPases. This study describes the use of conditionally immortalized murine pulmonary microvascular endothelial cells as a model for the study of TcsL functional activities. Point mutations that disrupt the glucosyltransferase, autoprocessing, or membrane localization activities were introduced into a recombinant version of TcsL, and the activities of these mutants were compared to those of wild-type toxin. We observed that all mutants are defective or impaired in cytotoxicity but differ in their modification of Rac1 and Ras. The data suggest a model where differences in GTPase localization dictate cellular responses to intoxication and highlight the importance of autoprocessing in the function of TcsL. IMPORTANCE Clostridium sordellii is a bacterium that can infect humans and cause serious disease and death. The principle virulence factor associated with clinical symptoms is a large protein toxin known as lethal toxin. The mechanism of lethal-toxin intoxication is assumed to be similar to that of the homologous toxins from C. difficile, but very few studies have been done in the context of endothelial cells, a relevant target in C. sordellii infections. This study was designed to test the role of the lethal-toxin enzymatic activities and membrane localization in endothelial cell toxicity and host substrate modification.Ryan CravenD. Borden LacyAmerican Society for MicrobiologyarticlecytotoxinsmembranesglucosylationGTPasesMicrobiologyQR1-502ENmSphere, Vol 1, Iss 1 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	cytotoxins membranes glucosylation GTPases Microbiology QR1-502
spellingShingle	cytotoxins membranes glucosylation GTPases Microbiology QR1-502 Ryan Craven D. Borden Lacy <named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
description	ABSTRACT Clostridium sordellii infections cause gangrene and edema in humans and gastrointestinal infections in livestock. One of the principle virulence factors is TcsL, a large protein toxin which glucosylates host GTPases to cause cytopathic and cytotoxic effects. TcsL has two enzymatic domains, an N-terminal glucosyltransferase domain (GTD) and an autoprocessing domain responsible for release of the GTD within the cell. The GTD can then use its N-terminal membrane localization domain (MLD) for orientation on membranes and modification of GTPases. This study describes the use of conditionally immortalized murine pulmonary microvascular endothelial cells as a model for the study of TcsL functional activities. Point mutations that disrupt the glucosyltransferase, autoprocessing, or membrane localization activities were introduced into a recombinant version of TcsL, and the activities of these mutants were compared to those of wild-type toxin. We observed that all mutants are defective or impaired in cytotoxicity but differ in their modification of Rac1 and Ras. The data suggest a model where differences in GTPase localization dictate cellular responses to intoxication and highlight the importance of autoprocessing in the function of TcsL. IMPORTANCE Clostridium sordellii is a bacterium that can infect humans and cause serious disease and death. The principle virulence factor associated with clinical symptoms is a large protein toxin known as lethal toxin. The mechanism of lethal-toxin intoxication is assumed to be similar to that of the homologous toxins from C. difficile, but very few studies have been done in the context of endothelial cells, a relevant target in C. sordellii infections. This study was designed to test the role of the lethal-toxin enzymatic activities and membrane localization in endothelial cell toxicity and host substrate modification.
format	article
author	Ryan Craven D. Borden Lacy
author_facet	Ryan Craven D. Borden Lacy
author_sort	Ryan Craven
title	<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
title_short	<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
title_full	<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
title_fullStr	<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
title_full_unstemmed	<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells
title_sort	<named-content content-type="genus-species">clostridium sordellii</named-content> lethal-toxin autoprocessing and membrane localization activities drive gtpase glucosylation profiles in endothelial cells
publisher	American Society for Microbiology
publishDate	2016
url	https://doaj.org/article/55346b51151e48caaabab25e992876e8
work_keys_str_mv	AT ryancraven namedcontentcontenttypegenusspeciesclostridiumsordelliinamedcontentlethaltoxinautoprocessingandmembranelocalizationactivitiesdrivegtpaseglucosylationprofilesinendothelialcells AT dbordenlacy namedcontentcontenttypegenusspeciesclostridiumsordelliinamedcontentlethaltoxinautoprocessingandmembranelocalizationactivitiesdrivegtpaseglucosylationprofilesinendothelialcells
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<named-content content-type="genus-species">Clostridium sordellii</named-content> Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells

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