Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.

The general stress response (GSR) in Listeria monocytogenes plays a critical role in the survival of this pathogen in the host gastrointestinal tract. The GSR is regulated by the alternative sigma factor B (σB), whose role in protection against acid stress is well established. Here, we investigated...

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Main Authors: Duarte N Guerreiro, M Graciela Pucciarelli, Teresa Tiensuu, Diana Gudynaite, Aoife Boyd, Jörgen Johansson, Francisco García-Del Portillo, Conor P O'Byrne
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-03-01
Series:PLoS Pathogens
Online Access:https://doi.org/10.1371/journal.ppat.1010213
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author Duarte N Guerreiro
M Graciela Pucciarelli
Teresa Tiensuu
Diana Gudynaite
Aoife Boyd
Jörgen Johansson
Francisco García-Del Portillo
Conor P O'Byrne
author_facet Duarte N Guerreiro
M Graciela Pucciarelli
Teresa Tiensuu
Diana Gudynaite
Aoife Boyd
Jörgen Johansson
Francisco García-Del Portillo
Conor P O'Byrne
author_sort Duarte N Guerreiro
collection DOAJ
description The general stress response (GSR) in Listeria monocytogenes plays a critical role in the survival of this pathogen in the host gastrointestinal tract. The GSR is regulated by the alternative sigma factor B (σB), whose role in protection against acid stress is well established. Here, we investigated the involvement of the stressosome, a sensory hub, in transducing low pH signals to induce the GSR. Mild acid shock (15 min at pH 5.0) activated σB and conferred protection against a subsequent lethal pH challenge. A mutant strain where the stressosome subunit RsbR1 was solely present retained the ability to induce σB activity at pH 5.0. The role of stressosome phosphorylation in signal transduction was investigated by mutating the putative phosphorylation sites in the core stressosome proteins RsbR1 (rsbR1-T175A, -T209A, -T241A) and RsbS (rsbS-S56A), or the stressosome kinase RsbT (rsbT-N49A). The rsbS S56A and rsbT N49A mutations abolished the response to low pH. The rsbR1-T209A and rsbR1-T241A mutants displayed constitutive σB activity. Mild acid shock upregulates invasion genes inlAB and stimulates epithelial cell invasion, effects that were abolished in mutants with an inactive or overactive stressosome. Overall, the results show that the stressosome is required for acid-induced activation of σB in L. monocytogenes. Furthermore, they show that RsbR1 can function independently of its paralogues and signal transduction requires RsbT-mediated phosphorylation of RsbS on S56 and RsbR1 on T209 but not T175. These insights shed light on the mechanisms of signal transduction that activate the GSR in L. monocytogenes in response to acidic environments, and highlight the role this sensory process in the early stages of the infectious cycle.
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spelling doaj.art-607ee03bb1d343feacf787f0e3836aad2022-12-22T01:46:12ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742022-03-01183e101021310.1371/journal.ppat.1010213Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.Duarte N GuerreiroM Graciela PucciarelliTeresa TiensuuDiana GudynaiteAoife BoydJörgen JohanssonFrancisco García-Del PortilloConor P O'ByrneThe general stress response (GSR) in Listeria monocytogenes plays a critical role in the survival of this pathogen in the host gastrointestinal tract. The GSR is regulated by the alternative sigma factor B (σB), whose role in protection against acid stress is well established. Here, we investigated the involvement of the stressosome, a sensory hub, in transducing low pH signals to induce the GSR. Mild acid shock (15 min at pH 5.0) activated σB and conferred protection against a subsequent lethal pH challenge. A mutant strain where the stressosome subunit RsbR1 was solely present retained the ability to induce σB activity at pH 5.0. The role of stressosome phosphorylation in signal transduction was investigated by mutating the putative phosphorylation sites in the core stressosome proteins RsbR1 (rsbR1-T175A, -T209A, -T241A) and RsbS (rsbS-S56A), or the stressosome kinase RsbT (rsbT-N49A). The rsbS S56A and rsbT N49A mutations abolished the response to low pH. The rsbR1-T209A and rsbR1-T241A mutants displayed constitutive σB activity. Mild acid shock upregulates invasion genes inlAB and stimulates epithelial cell invasion, effects that were abolished in mutants with an inactive or overactive stressosome. Overall, the results show that the stressosome is required for acid-induced activation of σB in L. monocytogenes. Furthermore, they show that RsbR1 can function independently of its paralogues and signal transduction requires RsbT-mediated phosphorylation of RsbS on S56 and RsbR1 on T209 but not T175. These insights shed light on the mechanisms of signal transduction that activate the GSR in L. monocytogenes in response to acidic environments, and highlight the role this sensory process in the early stages of the infectious cycle.https://doi.org/10.1371/journal.ppat.1010213
spellingShingle Duarte N Guerreiro
M Graciela Pucciarelli
Teresa Tiensuu
Diana Gudynaite
Aoife Boyd
Jörgen Johansson
Francisco García-Del Portillo
Conor P O'Byrne
Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
PLoS Pathogens
title Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
title_full Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
title_fullStr Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
title_full_unstemmed Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
title_short Acid stress signals are integrated into the σB-dependent general stress response pathway via the stressosome in the food-borne pathogen Listeria monocytogenes.
title_sort acid stress signals are integrated into the σb dependent general stress response pathway via the stressosome in the food borne pathogen listeria monocytogenes
url https://doi.org/10.1371/journal.ppat.1010213
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