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Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli
Type VI secretion systems (T6SSs) contribute to the pathogenicity of avian pathogenic Escherichia coli (APEC), one of the leading causative agents of sepsis and meningitis in poultry. The Hcp protein is a core component of the T6SS tail tube and acts as an exported receptor and a chaperone of effect...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Nature Publishing Group UK
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5874247/ https://www.ncbi.nlm.nih.gov/pubmed/29593238 http://dx.doi.org/10.1038/s41426-018-0042-0 |
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author | Ma, Jiale Sun, Min Pan, Zihao Song, Wenchao Lu, Chengping Yao, Huochun |
author_facet | Ma, Jiale Sun, Min Pan, Zihao Song, Wenchao Lu, Chengping Yao, Huochun |
author_sort | Ma, Jiale |
collection | PubMed |
description | Type VI secretion systems (T6SSs) contribute to the pathogenicity of avian pathogenic Escherichia coli (APEC), one of the leading causative agents of sepsis and meningitis in poultry. The Hcp protein is a core component of the T6SS tail tube and acts as an exported receptor and a chaperone of effectors. In this study, four distinct Hcp types (Ia, Ib, IIa, and IIb) were designated in Gram-negative bacteria, three of which were widely distributed in APEC. We detected divergence in transcription levels among three hcp clusters in 50% duck serum and demonstrated that hcp1 was upregulated by relieving Fur repression. Further analyses revealed that the host serum could activate the hcp2B operon by H-NS derepression to transcribe the downstream xmtU/xmtV pair for inter-bacterial antagonism. Notably, in a structural analysis based on the genetic classification, Hcp proteins exhibited significant differences in the extended loop regions, suggesting that these regions were related to their functional properties. Indeed, the variant region Vs2 (Loop L2, 3) in Hcp1 and Hcp2B was essential for the delivery of antibacterial effectors and the inhibition of macrophage phagocytosis. Further analyses using a duck model indicated that these Hcps play different roles in the pathogenic processes of APEC and immunoprotection. These results indicated that the functional differentiation of Hcp homologs was driven by differences in transcriptional regulation, extended loop regions, and effector delivery. |
format | Online Article Text |
id | pubmed-5874247 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-58742472018-03-30 Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli Ma, Jiale Sun, Min Pan, Zihao Song, Wenchao Lu, Chengping Yao, Huochun Emerg Microbes Infect Article Type VI secretion systems (T6SSs) contribute to the pathogenicity of avian pathogenic Escherichia coli (APEC), one of the leading causative agents of sepsis and meningitis in poultry. The Hcp protein is a core component of the T6SS tail tube and acts as an exported receptor and a chaperone of effectors. In this study, four distinct Hcp types (Ia, Ib, IIa, and IIb) were designated in Gram-negative bacteria, three of which were widely distributed in APEC. We detected divergence in transcription levels among three hcp clusters in 50% duck serum and demonstrated that hcp1 was upregulated by relieving Fur repression. Further analyses revealed that the host serum could activate the hcp2B operon by H-NS derepression to transcribe the downstream xmtU/xmtV pair for inter-bacterial antagonism. Notably, in a structural analysis based on the genetic classification, Hcp proteins exhibited significant differences in the extended loop regions, suggesting that these regions were related to their functional properties. Indeed, the variant region Vs2 (Loop L2, 3) in Hcp1 and Hcp2B was essential for the delivery of antibacterial effectors and the inhibition of macrophage phagocytosis. Further analyses using a duck model indicated that these Hcps play different roles in the pathogenic processes of APEC and immunoprotection. These results indicated that the functional differentiation of Hcp homologs was driven by differences in transcriptional regulation, extended loop regions, and effector delivery. Nature Publishing Group UK 2018-03-29 /pmc/articles/PMC5874247/ /pubmed/29593238 http://dx.doi.org/10.1038/s41426-018-0042-0 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Ma, Jiale Sun, Min Pan, Zihao Song, Wenchao Lu, Chengping Yao, Huochun Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title | Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title_full | Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title_fullStr | Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title_full_unstemmed | Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title_short | Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli |
title_sort | three hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic escherichia coli |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5874247/ https://www.ncbi.nlm.nih.gov/pubmed/29593238 http://dx.doi.org/10.1038/s41426-018-0042-0 |
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