Temporal regulation of σ B  by partner-switching mechanism at a distinct growth stage in  Bacillus cereus

Chen, Jung-Chi; Chang, Chuan-Fu; Hsu, Duen-Wei; Shu, Jwu-Ching; Chen, Hongyi; Chen, Chien‐Yen; Lu, Chi‐Yu; Chen, Chien‐Cheng

doi:10.1016/j.ijmm.2017.09.005

Cited by 7 publications

(8 citation statements)

References 43 publications

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“…However, the global regulator of branched-chain amino 2 and 3, and Supplementary Tables S5A and B). White color circles: known SigB signalling pathway as described in the literature [5,12,15,16], Grey and Black circles and boxes: new insight obtained in the current study (see text for details) acid limitation in Bacillus species, CodY, is found to be SigB-dependent upon heat shock in B. licheniformis [63]. Nonetheless, based on information obtained in this study, SigB does not regulate CodY in B. cereus, or B. subtilis [62].…”

Section: Discussionmentioning

confidence: 50%

“…The phosphorylated RsbY then dephosphorylates the anti-sigma factor antagonist RsbV, increasing its affinity to the anti-sigma factor RsbW and their subsequent association. The formation of RsbVW complexes releases RsbW from SigB, leading to SigB activation [12,14,15]. Without stressors, the methyltransferase RsbM methylates the S-helix of RsbK and prohibits its phosphate transfer to RsbY [14].…”

Section: Introductionmentioning

confidence: 99%

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SigB modulates expression of novel SigB regulon members via Bc1009 in non-stressed and heat-stressed cells revealing its alternative roles in Bacillus cereus

Yeak

Tempelaars

et al. 2023

BMC Microbiol

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Background The Bacillus cereus Sigma B (SigB) dependent general stress response is activated via the two-component RsbKY system, which involves a phosphate transfer from RsbK to RsbY. It has been hypothesized that the Hpr-like phosphocarrier protein (Bc1009) encoded by bc1009 in the SigB gene cluster may play a role in this transfer, thereby acting as a regulator of SigB activation. Alternatively, Bc1009 may be involved in the activation of a subset of SigB regulon members. Results We first investigated the potential role of bc1009 to act as a SigB regulator but ruled out this possibility as the deletion of bc1009 did not affect the expression of sigB and other SigB gene cluster members. The SigB-dependent functions of Bc1009 were further examined in B. cereus ATCC14579 via comparative proteome profiling (backed up by transcriptomics) of wt, Δbc1009 and ΔsigB deletion mutants under heat stress at 42 °C. This revealed 284 proteins displaying SigB-dependent alterations in protein expression levels in heat-stressed cells, including a subgroup of 138 proteins for which alterations were also Bc1009-dependent. Next to proteins with roles in stress defense, newly identified SigB and Bc1009-dependent proteins have roles in cell motility, signal transduction, transcription, cell wall biogenesis, and amino acid transport and metabolism. Analysis of lethal stress survival at 50 °C after pre-adaptation at 42 °C showed intermediate survival efficacy of Δbc1009 cells, highest survival of wt, and lowest survival of ΔsigB cells, respectively. Additional comparative proteome analysis of non-stressed wt and mutant cells at 30 °C revealed 96 proteins with SigB and Bc1009-dependent differences in levels: 51 were also identified under heat stress, and 45 showed significant differential expression at 30 °C. This includes proteins with roles in carbohydrate/ion transport and metabolism. Overlapping functions at 30 °C and 42 °C included proteins involved in motility, and ΔsigB and Δbc1009 cells showed reduced motility compared to wt cells in swimming assays at both temperatures. Conclusion Our results extend the B. cereus SigB regulon to > 300 members, with a novel role of SigB-dependent Bc1009 in the activation of a subregulon of > 180 members, conceivably via interactions with other transcriptional regulatory networks.

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Section: Discussionmentioning

confidence: 50%

Section: Introductionmentioning

confidence: 99%

SigB modulates expression of novel SigB regulon members via Bc1009 in non-stressed and heat-stressed cells revealing its alternative roles in Bacillus cereus

Yeak

Tempelaars

et al. 2023

BMC Microbiol

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“…By default, the methyltransferase (RsbM) methylates RsbK and negatively regulates SigB. Upon exposure to environmental/nutritional stressors, RsbK autophosphorylates and activates the RsbY phosphatase [ 27 , 28 ], and subsequent SigB activation takes place in the same way as for the stressosome and the RsbQP module [ 26 , 28 , 29 ]. However, not all of the above-mentioned SigB activation systems are present in all Bacillales.…”

Section: Introductionmentioning

confidence: 99%

Prediction and validation of novel SigB regulon members in Bacillus subtilis and regulon structure comparison to Bacillales members

et al. 2023

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Background Sigma factor B (SigB) is the central regulator of the general stress response in Bacillus subtilis and regulates a group of genes in response to various stressors, known as the SigB regulon members. Genes that are directly regulated by SigB contain a promotor binding motif (PBM) with a previously identified consensus sequence. Results In this study, refined SigB PBMs were derived and different spacer compositions and lengths (N12-N17) were taken into account. These were used to identify putative SigB-regulated genes in the B. subtilis genome, revealing 255 genes: 99 had been described in the literature and 156 genes were newly identified, increasing the number of SigB putative regulon members (with and without a SigB PBM) to > 500 in B. subtilis. The 255 genes were assigned to five categories (I-V) based on their similarity to the original SigB consensus sequences. The functionalities of selected representatives per category were assessed using promoter-reporter fusions in wt and ΔsigB mutants upon exposure to heat, ethanol, and salt stress. The activity of the PrsbV (I) positive control was induced upon exposure to all three stressors. PytoQ (II) showed SigB-dependent activity only upon exposure to ethanol, whereas PpucI (II) with a N17 spacer and PylaL (III) with a N16 spacer showed mild induction regardless of heat/ethanol/salt stress. PywzA (III) and PyaaI (IV) displayed ethanol-specific SigB-dependent activities despite a lower-level conserved − 10 binding motif. PgtaB (V) was SigB-induced under ethanol and salt stress while lacking a conserved − 10 binding region. The activities of PygaO and PykaA (III) did not show evident changes under the conditions tested despite having a SigB PBM that highly resembled the consensus. The identified extended SigB regulon candidates in B. subtilis are mainly involved in coping with stress but are also engaged in other cellular processes. Orthologs of SigB regulon candidates with SigB PBMs were identified in other Bacillales genomes, but not all showed a SigB PBM. Additionally, genes involved in the integration of stress signals to activate SigB were predicted in these genomes, indicating that SigB signaling and regulon genes are species-specific. Conclusion The entire SigB regulatory network is sophisticated and not yet fully understood even for the well-characterized organism B. subtilis 168. Knowledge and information gained in this study can be used in further SigB studies to uncover a complete picture of the role of SigB in B. subtilis and other species.

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“…Of the Rsb proteins, RsbW proteins are usually composed of ~157–161 amino acid residues, exist as the dimers in the aqueous solution, blocks the SigB-mediated transcription, and causes phosphorylation of a Ser residue in RsbV [ 1 – 3 , 6 – 9 ]. The physical interaction between RsbW and RsbV or SigB was shown by both in vitro and in vivo probes [ 1 – 3 , 6 , 8 , 10 , 11 ]. The binding stoichiometry of RsbW to SigB is 2:1 and that to RsbV is 2:2 [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…The binding stoichiometry of RsbW to SigB is 2:1 and that to RsbV is 2:2 [ 8 ]. The affinity of RsbW to RsbV is higher than that to SigB, indicating the preferential formation of a complex between RsbW and the dephosphorylated RsbV [ 8 , 10 ]. Collectively, RsbV performs as an anti-anti-sigma factor, whereas, RsbW works both as an anti-sigma factor and a serine kinase.…”

Section: Introductionmentioning

confidence: 99%

A staphylococcal anti-sigma factor possesses a single-domain, carries different denaturant-sensitive regions and unfolds via two intermediates

et al. 2018

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RsbW, an anti-sigma factor possessing kinase activity, is expressed by many Gram-positive bacteria including Staphylococcus aureus. To obtain clues about the domain structure and the folding-unfolding mechanism of RsbW, we have elaborately studied rRsbW, a recombinant S. aureus RsbW. Sequence analysis of the protein fragments, generated by the limited proteolysis of rRsbW, has proposed it to be a single-domain protein. The unfolding of rRsbW in the presence of GdnCl or urea was completely reversible in nature and occurred through the formation of at least two intermediates. The structure, shape, and the surface hydrophobicity of no intermediate completely matches with those of other intermediates or the native rRsbW. Interestingly, one of the intermediates, formed in the presence of less GdnCl concentrations, has a molten globule-like structure. Conversely, all of the intermediates, like native rRsbW, exist as dimers in aqueous solution. The putative molten globule and the urea-generated intermediates also have retained some kinase activity. Additionally, the putative ATP binding site/catalytic site of rRsbW shows higher denaturant sensitivity than the tentative dimerization region of this enzyme.

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Temporal regulation of σ B by partner-switching mechanism at a distinct growth stage in Bacillus cereus

Cited by 7 publications

References 43 publications

SigB modulates expression of novel SigB regulon members via Bc1009 in non-stressed and heat-stressed cells revealing its alternative roles in Bacillus cereus

SigB modulates expression of novel SigB regulon members via Bc1009 in non-stressed and heat-stressed cells revealing its alternative roles in Bacillus cereus

Prediction and validation of novel SigB regulon members in Bacillus subtilis and regulon structure comparison to Bacillales members

A staphylococcal anti-sigma factor possesses a single-domain, carries different denaturant-sensitive regions and unfolds via two intermediates

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