Anatomy of the bacitracin resistance network in <scp><i>B</i></scp><i>acillus subtilis</i>

Radeck, Jara; Gebhard, Susanne; Orchard, Peter; Kirchner, Marion; Bauer, Sonja; Mascher, Thorsten; Fritz, Georg

doi:10.1111/mmi.13336

Cited by 61 publications

(100 citation statements)

References 51 publications

(84 reference statements)

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“…We might have expected bacitracin (which binds directly to UPP) to trigger a response similar to the response to UPP-Pase depletion. However, despite several similarities, bacitracin additionally elicits strong (albeit transient) induction of the BceR and LiaR regulons after 5 min of treatment (51). This activation can happen at bacitracin concentrations well below the MIC and does not depend on cell wall damage (52).…”

Section: Figmentioning

confidence: 99%

Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis

et al. 2016

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The integrity of the bacterial cell envelope is essential to sustain life by countering the high turgor pressure of the cell and providing a barrier against chemical insults. In Bacillus subtilis, synthesis of both peptidoglycan and wall teichoic acids requires a common C 55 lipid carrier, undecaprenyl-pyrophosphate (UPP), to ferry precursors across the cytoplasmic membrane. The synthesis and recycling of UPP requires a phosphatase to generate the monophosphate form Und-P, which is the substrate for peptidoglycan and wall teichoic acid synthases. Using an optimized clustered regularly interspaced short palindromic repeat (CRISPR) system with catalytically inactive ("dead") CRISPR-associated protein 9 (dCas9)-based transcriptional repression system (CRISPR interference [CRISPRi]), we demonstrate that B. subtilis requires either of two UPP phosphatases, UppP or BcrC, for viability. We show that a third predicted lipid phosphatase (YodM), with homology to diacylglycerol pyrophosphatases, can also support growth when overexpressed. Depletion of UPP phosphatase activity leads to morphological defects consistent with a failure of cell envelope synthesis and strongly activates the M -dependent cell envelope stress response, including bcrC, which encodes one of the two UPP phosphatases. These results highlight the utility of an optimized CRISPRi system for the investigation of synthetic lethal gene pairs, clarify the nature of the B. subtilis UPP-Pase enzymes, and provide further evidence linking the M regulon to cell envelope homeostasis pathways. IMPORTANCEThe emergence of antibiotic resistance among bacterial pathogens is of critical concern and motivates efforts to develop new therapeutics and increase the utility of those already in use. The lipid II cycle is one of the most frequently targeted processes for antibiotics and has been intensively studied. Despite these efforts, some steps have remained poorly defined, partly due to genetic redundancy. CRISPRi provides a powerful tool to investigate the functions of essential genes and sets of genes. Here, we used an optimized CRISPRi system to demonstrate functional redundancy of two UPP phosphatases that are required for the conversion of the initially synthesized UPP lipid carrier to Und-P, the substrate for the synthesis of the initial lipid-linked precursors in peptidoglycan and wall teichoic acid synthesis.

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Section: Figmentioning

confidence: 99%

Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis

et al. 2016

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“…But what was still missing was a proof that these signaling systems indeed form a regulatory network, that is, interact with and influence each other's behavior such that the overall response can only be described and understood in light of all of its constituents. Most recently, the first insights into this interdependence have been provided (Radeck et al 2016). This work demonstrates a clear hierarchy, co-dependence and active redundancy of signaling systems involved in mediating the bacitracin CESR, as will be summarized below (Fig.…”

Section: The Interdependent Picture: a Network At Lastmentioning

confidence: 91%

“…Data points and error bars indicate means and standard deviations derived from at least three biological replicates. Data are based on Radeck et al (2016) recently show that only the last scenario is compatible with all available data, suggesting that the sensory complex of BceB-BceS acts as a 'flux-sensor' that measures the load of individual transporters (Fritz et al 2015). This sensory strategy then allows the cell to detect its current capacity to deal with the antibiotic challenge and thus precisely respond to the need for more transporters.…”

Section: The Bcers-bceab Complex Acts As An Antibiotic Flux Sensormentioning

confidence: 96%

“…Upon stimulus perception-triggered by cell envelope perturbationsYhdKL release σ M into the cytoplasm where it recruits the RNA polymerase to its target promoters, including P bcrC (Helmann 2016;Horsburgh and Moir 1999) of a functional cell wall biosynthetic machinery, potentially requiring lipid I and/or lipid II, to sense the downstream effects of the five antibiotics mentioned before. This prompted the notion that the LiaFSR system might act as an indirect, damage-sensing signal-transducing system, in line with its role as a secondary resistance determinant that is only activated if the primary resistance determinant BceAB provides incomplete protection (Radeck et al 2016), as discussed below.…”

Section: The Liars-liaf Three-component System Responds To Inhibitionmentioning

confidence: 98%

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The cell envelope stress response of Bacillus subtilis: from static signaling devices to dynamic regulatory network

2016

Self Cite

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The cell envelope stress response (CESR) encompasses all regulatory events that enable a cell to protect the integrity of its envelope, an essential structure of any bacterial cell. The underlying signaling network is particularly well understood in the Gram-positive model organism Bacillus subtilis. It consists of a number of two-component systems (2CS) and extracytoplasmic function σ factors that together regulate the production of both specific resistance determinants and general mechanisms to protect the envelope against antimicrobial peptides targeting the biogenesis of the cell wall. Here, we summarize the current picture of the B. subtilis CESR network, from the initial identification of the corresponding signaling devices to unraveling their interdependence and the underlying regulatory hierarchy within the network. In the course of detailed mechanistic studies, a number of novel signaling features could be described for the 2CSs involved in mediating CESR. This includes a novel class of so-called intramembrane-sensing histidine kinases (IM-HKs), which-instead of acting as stress sensors themselves-are activated via interprotein signal transfer. Some of these IM-HKs are involved in sensing the flux of antibiotic resistance transporters, a unique mechanism of responding to extracellular antibiotic challenge.

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“…Whether LiaH also exerts regulatory functions is unclear. A modest inhibitory effect of LiaH on the liaI promoter has been observed in stressed cultures [42], and positive autoregulation of LiaIH has also been postulated [45]. Thus, LiaH lacks the prominent regulatory function exerted by PspA over the cognate transcription factor PspF in Gram-negative organisms.…”

Section: Variation 1: the Two Psp Systems Of B Subtilismentioning

confidence: 96%

Protecting from Envelope Stress: Variations on the Phage-Shock-Protein Theme

Manganelli¹,

Gennaro²

2017

Trends in Microbiology

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During envelope stress, critical inner-membrane functions are preserved by the phage-shockprotein (Psp) system, a stress response that emerged from work with Escherichia coli and other Gram-negative bacteria. Reciprocal regulatory interactions and multiple effector functions are well documented in these organisms. Searches for the Psp system across phyla reveals conservation of only one protein, PspA. However, examination of Firmicutes and Actinobacteria reveals that PspA orthologs associate with non-orthologous regulatory and effector proteins retaining functions similar to those in Gram-negative counterparts. Conservation across phyla emphasizes the longstanding importance of the Psp system in prokaryotes, while inter-and intra-phyla variations within the system indicate adaptation to different cell envelope structures, bacterial lifestyles, and/or bacterial morphogenetic strategies.

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Anatomy of the bacitracin resistance network in Bacillus subtilis

Cited by 61 publications

References 51 publications

Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis

Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis

The cell envelope stress response of Bacillus subtilis: from static signaling devices to dynamic regulatory network

Protecting from Envelope Stress: Variations on the Phage-Shock-Protein Theme

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