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Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8
Campylobacter jejuni express the high temperature requirement protein A (HtrA), a secreted serine protease, which is implicated in virulence properties of the pathogen. Previous studies have shown that C. jejuni HtrA can cleave the epithelial transmembrane proteins occludin and E-cadherin in the tig...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7752809/ https://www.ncbi.nlm.nih.gov/pubmed/33364202 http://dx.doi.org/10.3389/fcimb.2020.590186 |
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author | Sharafutdinov, Irshad Esmaeili, Delara Soltan Harrer, Aileen Tegtmeyer, Nicole Sticht, Heinrich Backert, Steffen |
author_facet | Sharafutdinov, Irshad Esmaeili, Delara Soltan Harrer, Aileen Tegtmeyer, Nicole Sticht, Heinrich Backert, Steffen |
author_sort | Sharafutdinov, Irshad |
collection | PubMed |
description | Campylobacter jejuni express the high temperature requirement protein A (HtrA), a secreted serine protease, which is implicated in virulence properties of the pathogen. Previous studies have shown that C. jejuni HtrA can cleave the epithelial transmembrane proteins occludin and E-cadherin in the tight and adherens junctions, respectively. In the present report, we studied the interaction of HtrA with another human tight junction protein, claudin-8. Confocal immunofluorescence experiments have shown that C. jejuni infection of the intestinal polarized epithelial cells in vitro leads to a relocation of claudin-8. Wild-type C. jejuni induced the downregulation of claudin-8 signals in the tight junctions and an accumulation of claudin-8 agglomerates in the cytoplasm, which were not seen during infection with isogenic ΔhtrA knockout deletion or protease-inactive S197A point mutants. Western blotting of protein samples from infected vs. uninfected cells revealed that an 18-kDa carboxy-terminal fragment is cleaved-off from the 26-kDa full-length claudin-8 protein, but not during infection with the isogenic ΔhtrA mutant. These results were confirmed by in vitro cleavage assays using the purified recombinant C. jejuni HtrA and human claudin-8 proteins. Recombinant HtrA cleaved purified claudin-8 in vitro giving rise to the same 18-kDa sized carboxy-terminal cleavage product. Mapping studies revealed that HtrA cleavage occurs in the first extracellular loop of claudin-8. Three-dimensional modeling of the claudin-8 structure identified an exposed HtrA cleavage site between the amino acids alanine 58 and asparagine 59, which is in well agreement with the mapping studies. Taken together, HtrA operates as a secreted virulence factor targeting multiple proteins both in the tight and adherens junctions. This strategy may help the bacteria to open the cell-to-cell junctions, and to transmigrate across the intestinal epithelium by a paracellular mechanism and establish an acute infection. |
format | Online Article Text |
id | pubmed-7752809 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-77528092020-12-23 Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 Sharafutdinov, Irshad Esmaeili, Delara Soltan Harrer, Aileen Tegtmeyer, Nicole Sticht, Heinrich Backert, Steffen Front Cell Infect Microbiol Cellular and Infection Microbiology Campylobacter jejuni express the high temperature requirement protein A (HtrA), a secreted serine protease, which is implicated in virulence properties of the pathogen. Previous studies have shown that C. jejuni HtrA can cleave the epithelial transmembrane proteins occludin and E-cadherin in the tight and adherens junctions, respectively. In the present report, we studied the interaction of HtrA with another human tight junction protein, claudin-8. Confocal immunofluorescence experiments have shown that C. jejuni infection of the intestinal polarized epithelial cells in vitro leads to a relocation of claudin-8. Wild-type C. jejuni induced the downregulation of claudin-8 signals in the tight junctions and an accumulation of claudin-8 agglomerates in the cytoplasm, which were not seen during infection with isogenic ΔhtrA knockout deletion or protease-inactive S197A point mutants. Western blotting of protein samples from infected vs. uninfected cells revealed that an 18-kDa carboxy-terminal fragment is cleaved-off from the 26-kDa full-length claudin-8 protein, but not during infection with the isogenic ΔhtrA mutant. These results were confirmed by in vitro cleavage assays using the purified recombinant C. jejuni HtrA and human claudin-8 proteins. Recombinant HtrA cleaved purified claudin-8 in vitro giving rise to the same 18-kDa sized carboxy-terminal cleavage product. Mapping studies revealed that HtrA cleavage occurs in the first extracellular loop of claudin-8. Three-dimensional modeling of the claudin-8 structure identified an exposed HtrA cleavage site between the amino acids alanine 58 and asparagine 59, which is in well agreement with the mapping studies. Taken together, HtrA operates as a secreted virulence factor targeting multiple proteins both in the tight and adherens junctions. This strategy may help the bacteria to open the cell-to-cell junctions, and to transmigrate across the intestinal epithelium by a paracellular mechanism and establish an acute infection. Frontiers Media S.A. 2020-12-08 /pmc/articles/PMC7752809/ /pubmed/33364202 http://dx.doi.org/10.3389/fcimb.2020.590186 Text en Copyright © 2020 Sharafutdinov, Esmaeili, Harrer, Tegtmeyer, Sticht and Backert http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Cellular and Infection Microbiology Sharafutdinov, Irshad Esmaeili, Delara Soltan Harrer, Aileen Tegtmeyer, Nicole Sticht, Heinrich Backert, Steffen Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title |
Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title_full |
Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title_fullStr |
Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title_full_unstemmed |
Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title_short |
Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8 |
title_sort | campylobacter jejuni serine protease htra cleaves the tight junction component claudin-8 |
topic | Cellular and Infection Microbiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7752809/ https://www.ncbi.nlm.nih.gov/pubmed/33364202 http://dx.doi.org/10.3389/fcimb.2020.590186 |
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