Role of Hsp100/Clp Protease Complexes in Controlling the Regulation of Motility in Bacillus subtilis

Molière, Noël; Hoßmann, Jörn; Schäfer, Heinrich; Turgay, Kürşad

doi:10.3389/fmicb.2016.00315

Cited by 19 publications

(23 citation statements)

References 75 publications

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“…rbsD, ganP, licH) were less down-regulated or even induced at 48˚C in the (p)ppGpp˚strain ( Fig 4B). In contrast, motility-genes were particularly strongly down-regulated by heat in the (p)ppGppm utant ( Fig 4B, S5 and S6 Figs), while the down-regulation of these genes appeared not to be significant in wild type cells at 48˚C (median 1.14-fold change, S6 Fig) [64].…”

Section: Transcriptome Changes In the Presence And Absence Of (P)ppgpmentioning

confidence: 92%

The alarmones (p)ppGpp are part of the heat shock response of Bacillus subtilis

et al. 2020

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Bacillus subtilis cells are well suited to study how bacteria sense and adapt to proteotoxic stress such as heat, since temperature fluctuations are a major challenge to soil-dwelling bacteria. Here, we show that the alarmones (p)ppGpp, well known second messengers of nutrient starvation, are also involved in the heat stress response as well as the development of thermo-resistance. Upon heat-shock, intracellular levels of (p)ppGpp rise in a rapid but transient manner. The heat-induced (p)ppGpp is primarily produced by the ribosome-associated alarmone synthetase Rel, while the small alarmone synthetases RelP and RelQ seem not to be involved. Furthermore, our study shows that the generated (p)ppGpp pulse primarily acts at the level of translation, and only specific genes are regulated at the transcriptional level. These include the down-regulation of some translation-related genes and the up-regulation of hpf, encoding the ribosome-protecting hibernation-promoting factor. In addition, the alarmones appear to interact with the activity of the stress transcription factor Spx during heat stress. Taken together, our study suggests that (p)ppGpp modulates the translational capacity at elevated temperatures and thereby allows B. subtilis cells to respond to proteotoxic stress, not only by raising the cellular repair capacity, but also by decreasing translation to concurrently reduce the protein load on the cellular protein quality control system. Author summaryWe observed that the second messenger (p)ppGpp, known to be synthesized by the ribosome-associated Rel synthetase upon nutrient starvation during the stringent response, is also intricately involved in the stress response of B. subtilis cells and can act as a pleiotropic regulator during the adaptation to heat stress. (p)ppGpp can slow down and modulate PLOS GENETICS PLOS Genetics | https://doi.

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Section: Transcriptome Changes In the Presence And Absence Of (P)ppgpmentioning

confidence: 92%

The alarmones (p)ppGpp are part of the heat shock response of Bacillus subtilis

et al. 2020

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“…In contrast, motility-genes were particularly strongly down-regulated by heat in the (p)ppGpp 0 mutant (median 3.0-fold change, Fig. 4C, S6B, S7), while the down-regulation of these genes appeared to be not significant in wildtype cells at 48 °C (median 1.14-fold change, S7) [55]. Notably, the expression of the hpf and ilvB transcripts, the transcription of which is positively regulated by the SR, was lower during heat stress in the (p)ppGpp 0 strain compared to wildtype cells ( hpf : 3.7-fold lower in (p)ppGpp 0 cells relative to wildtype at 50 °C, ilvB : 1.6-fold lower, Fig.…”

Section: Resultsmentioning

confidence: 99%

The alarmone (p)ppGpp is part of the heat shock response ofBacillus subtilis

Schäfer

Beckert

Steinchen

et al. 2019

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27 Here, B. subtilis was used as a model organism to investigate how cells respond and adapt to 28 proteotoxic stress conditions. Our experiments suggested that the stringent response, caused 29 by raised levels of the (p)ppGpp alarmone, plays a role during thermotolerance development 30 and the heat shock response. Accordingly, our experiments revealed a rapid increase of 31 cellular (p)ppGpp levels upon heat shock as well as salt-and oxidative stress. Strains lacking 32 (p)ppGpp exhibited increased stress sensitivity, while raised (p)ppGpp levels conferred 33 increased stress tolerance to heat-and oxidative stress. During thermotolerance development, 34 stress response genes were highly up-regulated together with a concurrent transcriptional 35 down-regulation of the rRNA, which was influenced by the second messenger (p)ppGpp and 36 the transcription factor Spx. Remarkably, we observed that (p)ppGpp appeared to control the 37 cellular translational capacity and that during heat stress the raised cellular levels of the 38 alarmone were able to curb the rate of protein synthesis. Furthermore, (p)ppGpp controls the 39 heat-induced expression of Hpf and thus the formation of translationally inactive 100S 40 disomes. These results indicate that B. subtilis cells respond to heat-mediated protein 41 unfolding and aggregation, not only by raising the cellular repair capacity, but also by 42 decreasing translation involving (p)ppGpp mediated stringent response to concurrently reduce 43 the protein load for the cellular protein quality control system. 44Author Summary 45 Here we demonstrate that the bacterial stringent response, which is known to slow down 46 translation upon sensing nutrient starvation, is also intricately involved in the stress response 47 of B. subtilis cells. The second messengers (p)ppGpp act as pleiotropic regulators during the 48 adaptation to heat stress. (p)ppGpp slows down translation and is also involved in the 49 transcriptional down-regulation of the translation machinery, together with the transcriptional 3 50 stress regulator Spx. The stress-induced elevation of cellular (p)ppGpp levels confers 51 increased stress tolerance and facilitates an improved protein homeostasis by reducing the 52 load on the protein quality control system. 53Introduction 54 Bacteria have evolved complex and diverse regulatory networks to sense and respond to 55 changes in the environment, which can include physical stresses or nutrient limitations [1].56 The protein quality control system (PQS) comprises a conserved set of chaperones and 57 proteases that monitor and maintain protein homeostasis is present in all cells. Various 58 physical stresses, such as heat stress, favor the unfolding and aggregation of cellular proteins, 59 which can be sensed by heat shock response systems, allowing an appropriate cellular stress 60 response. This response includes the induction of the expression of chaperones and proteases 61 of the PQS, also known as heat shock proteins [2,3]. 62Interestingly, in all cells including B. ...

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“…The transcription levels of degU, swrA , and pgsB which are related to γ -PGA biosynthesis were markedly increased in the ycgN deletion strain. In recent researches, DegU was proposed to be under control of the redox-sensing regulators ClpXP/Spx (56-58). Therefore, the intracellular ROS, induced by ycgN deletion, promoted the transcription level of degU probably by activating Spx.…”

Section: Resultsmentioning

confidence: 99%