Bacteria use a variety of systems to sense stress and mount an appropriate response to assure 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^B. Each stressosome includes 40 RsbR proteins, representing four paralogous (RsbRA, RsbRB, RsbRC, and RsbRD) putative stress sensors. Population-level analyses suggested that the RsbR paralogs are largely redundant, while our prior work using microfluidics-coupled fluorescence microscopy uncovered differences among the RsbR paralogs’ σ^B response profiles with respect to timing and intensity when facing an identical stressor.

We used microfluidics and fluorescence microscopy to address the question of whether the σ^B responses mediated by each paralog differ in the presence of different environmental stressors: can they distinguish among stressors? Wild-type cells (with all four paralogs) and RsbRA-only cells activate σ^B with characteristic transient response timing irrespective of stressor but show varying response magnitude. However, cells with other individual RsbR paralogs show distinct timing and magnitude in their responses to ethanol, salt, oxidative and acid stress, implying that RsbR proteins can distinguish among stressors. To show this distinct timing, we quantified time-lapse image series of cells with a fluorescent σ^B transcriptional reporter. Representative videos of time-lapse image series and the results of our quantitation for each RsbR paralog in each stress condition are included in this dataset.

We also probed the relative importance of each half of each RsbR paralog. Experiments with hybrid fusion proteins comprising the N-terminal half of one paralog and the C-terminal half of another argued that the N-terminal identity influences response magnitude and that determinants in both halves of RsbRA are important for its stereotypical transient σ^B response timing. Time-lapse videos for each hybrid fusion protein and the corresponding quantification of these data are also included in the dataset.

Please see the README document and the accompanying published article: Hamm CW, Butler R, and Cabeen MT. 2022. Bacillus subtilis Stressosome Sensor Protein Sequences Govern the Ability to Distinguish among Environmental Stressors and Elicit Different σ^B Response Profiles.

Please see the README document and the accompanying published article: Hamm CW, Butler R, and Cabeen MT. 2022. Bacillus subtilis Stressosome Sensor Protein Sequences Govern the Ability to Distinguish among Environmental Stressors and Elicit Different σ^B Response Profiles.