Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis

Abstract Bacillus subtilis uses cytoplasmic complexes called stressosomes to initiate the σB-mediated general stress response to environmental stress. Each stressosome comprises two types of proteins — RsbS and four paralogous RsbR proteins — that are thought to sequester the RsbT protein until stre...

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Main Authors: Rabindra Khadka, Brannon Maravich, Natalie Demarest, Mitchell Hartwig, Andrew Tom, Niloy Kumar Das, Matthew T. Cabeen
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-56871-1
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author Rabindra Khadka
Brannon Maravich
Natalie Demarest
Mitchell Hartwig
Andrew Tom
Niloy Kumar Das
Matthew T. Cabeen
author_facet Rabindra Khadka
Brannon Maravich
Natalie Demarest
Mitchell Hartwig
Andrew Tom
Niloy Kumar Das
Matthew T. Cabeen
author_sort Rabindra Khadka
collection DOAJ
description Abstract Bacillus subtilis uses cytoplasmic complexes called stressosomes to initiate the σB-mediated general stress response to environmental stress. Each stressosome comprises two types of proteins — RsbS and four paralogous RsbR proteins — that are thought to sequester the RsbT protein until stress causes RsbT release and subsequent σB activation. RsbR proteins have been assumed to sense stress, but evidence for their sensing function has been elusive, and the identity of the true sensor has remained unknown. Here, we conduct an alanine-scanning analysis of the putative sensing domain of one of the RsbR paralogs, RsbRA. We find that single substitutions impact but do not abolish the σB response, suggesting that RsbRA has a key role in σB response dynamics and is “tunable” and robust to substitution, but not directly supporting a sensing function. Surprisingly, deletion of the stressosome does not abolish environmental stress-inducible σB activity and instead leads to a stronger and longer-lived response than in strains with stressosomes. Finally, we show that RsbT is necessary for the stressosome-independent response and that its kinase activity is also important. RsbT thus has a previously unappreciated role in initiating stress responses and may itself be a stress sensor in the general stress response.
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spelling doaj-art-321948fa80ce4bf986789a88f8f0ddd92025-08-20T03:00:58ZengNature PortfolioNature Communications2041-17232025-02-0116111610.1038/s41467-025-56871-1Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilisRabindra Khadka0Brannon Maravich1Natalie Demarest2Mitchell Hartwig3Andrew Tom4Niloy Kumar Das5Matthew T. Cabeen6Department of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityDepartment of Microbiology and Molecular Genetics, Oklahoma State UniversityAbstract Bacillus subtilis uses cytoplasmic complexes called stressosomes to initiate the σB-mediated general stress response to environmental stress. Each stressosome comprises two types of proteins — RsbS and four paralogous RsbR proteins — that are thought to sequester the RsbT protein until stress causes RsbT release and subsequent σB activation. RsbR proteins have been assumed to sense stress, but evidence for their sensing function has been elusive, and the identity of the true sensor has remained unknown. Here, we conduct an alanine-scanning analysis of the putative sensing domain of one of the RsbR paralogs, RsbRA. We find that single substitutions impact but do not abolish the σB response, suggesting that RsbRA has a key role in σB response dynamics and is “tunable” and robust to substitution, but not directly supporting a sensing function. Surprisingly, deletion of the stressosome does not abolish environmental stress-inducible σB activity and instead leads to a stronger and longer-lived response than in strains with stressosomes. Finally, we show that RsbT is necessary for the stressosome-independent response and that its kinase activity is also important. RsbT thus has a previously unappreciated role in initiating stress responses and may itself be a stress sensor in the general stress response.https://doi.org/10.1038/s41467-025-56871-1
spellingShingle Rabindra Khadka
Brannon Maravich
Natalie Demarest
Mitchell Hartwig
Andrew Tom
Niloy Kumar Das
Matthew T. Cabeen
Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
Nature Communications
title Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
title_full Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
title_fullStr Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
title_full_unstemmed Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
title_short Stressosome-independent but RsbT-dependent environmental stress sensing in Bacillus subtilis
title_sort stressosome independent but rsbt dependent environmental stress sensing in bacillus subtilis
url https://doi.org/10.1038/s41467-025-56871-1
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AT mitchellhartwig stressosomeindependentbutrsbtdependentenvironmentalstresssensinginbacillussubtilis
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