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Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins

The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms...

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Detalles Bibliográficos
Autores principales: Filipi, Katerina, Rahman, Waheed Ur, Osickova, Adriana, Osicka, Radim
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8953716/
https://www.ncbi.nlm.nih.gov/pubmed/35336094
http://dx.doi.org/10.3390/microorganisms10030518
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author Filipi, Katerina
Rahman, Waheed Ur
Osickova, Adriana
Osicka, Radim
author_facet Filipi, Katerina
Rahman, Waheed Ur
Osickova, Adriana
Osicka, Radim
author_sort Filipi, Katerina
collection PubMed
description The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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spelling pubmed-89537162022-03-26 Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins Filipi, Katerina Rahman, Waheed Ur Osickova, Adriana Osicka, Radim Microorganisms Review The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections. MDPI 2022-02-27 /pmc/articles/PMC8953716/ /pubmed/35336094 http://dx.doi.org/10.3390/microorganisms10030518 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/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 (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Review
Filipi, Katerina
Rahman, Waheed Ur
Osickova, Adriana
Osicka, Radim
Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title_full Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title_fullStr Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title_full_unstemmed Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title_short Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins
title_sort kingella kingae rtxa cytotoxin in the context of other rtx toxins
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8953716/
https://www.ncbi.nlm.nih.gov/pubmed/35336094
http://dx.doi.org/10.3390/microorganisms10030518
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