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The human pathogen Listeria monocytogenes can cope with severe environmental challenges, for which the high molecular weight stressosome complex acts as the sensing hub in a complicated signal transduction pathway. Here, we show the dynamics and functional roles of the stressosome protein RsbR1 and its paralogue, the blue-light receptor RsbL, using photo-activated localization microscopy combined with single-particle tracking and single-molecule displacement mapping and supported by physiological studies. In live cells, RsbR1 is present in multiple states: in protomers with RsbS, large clusters of stressosome complexes, and in connection with the plasma membrane via Prli42. RsbL diffuses freely in the cytoplasm but forms clusters upon exposure to light. The clustering of RsbL is independent of the presence of Prli42. Our work provides a comprehensive view of the spatial organization and intracellular dynamics of the stressosome proteins in L. monocytogenes, which paves the way towards uncovering the stress-sensing mechanism of this signal transduction pathway.
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http://dx.doi.org/10.1038/s42003-023-04423-y | DOI Listing |
Res Sq
May 2025
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA.
Bacterial pathogens rely on their ability to sense and respond to environmental stressors to survive and maintain virulence. The stressosome, a 1.8-megadalton nanomachine, serves as a critical sensor and regulator of the general stress response.
View Article and Find Full Text PDFNat Commun
February 2025
Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA.
Bacillus subtilis uses cytoplasmic complexes called stressosomes to initiate the σ-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 σ 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.
View Article and Find Full Text PDFmSphere
February 2024
Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA.
Unlabelled: The Gram-positive model organism responds to environmental stressors by activating the alternative sigma factor σ. The sensing apparatus upstream of σ activation is thought to consist of cytoplasmic stressosomes-megadalton-sized protein complexes that include five paralogous proteins known as RsbRs. The RsbRs are presumed to be involved in stress sensing and the subsequent response.
View Article and Find Full Text PDFCommun Biol
January 2023
Department of Biochemistry, University of Groningen, Groningen, the Netherlands.
The human pathogen Listeria monocytogenes can cope with severe environmental challenges, for which the high molecular weight stressosome complex acts as the sensing hub in a complicated signal transduction pathway. Here, we show the dynamics and functional roles of the stressosome protein RsbR1 and its paralogue, the blue-light receptor RsbL, using photo-activated localization microscopy combined with single-particle tracking and single-molecule displacement mapping and supported by physiological studies. In live cells, RsbR1 is present in multiple states: in protomers with RsbS, large clusters of stressosome complexes, and in connection with the plasma membrane via Prli42.
View Article and Find Full Text PDFmBio
December 2022
Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA.
Bacteria use a variety of systems to sense stress and mount an appropriate response to ensure fitness and survival. Bacillus subtilis uses stressosomes-cytoplasmic multiprotein complexes-to sense environmental stressors and enact the general stress response by activating the alternative sigma factor σ. Each stressosome includes 40 RsbR proteins, representing four paralogous (RsbRA, RsbRB, RsbRC, and RsbRD) putative stress sensors.
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