Microbiology
Self-cleavage of the Pseudomonas aeruginosa Cell-surface Signaling Anti-sigma Factor FoxR Occurs through an N-O Acyl Rearrangement
The Fox system of Pseudomonas aeruginosa is a cell-surface signaling (CSS) pathway employed by the bacterium to sense and respond to the presence of the heterologous siderophore ferrioxamine in the environment. This regulatory pathway controls the transcription of the foxA ferrioxamine receptor gene through the extracytoplasmic function sigma factor σFoxI. In the absence of ferrioxamine, the activity of σFoxI is inhibited by the transmembrane anti-sigma factor FoxR. Upon binding of ferrioxamine by the FoxA receptor, FoxR is processed by a complex proteolytic cascade leading to the release and activation of σFoxI.Activity of a Bacterial Cell Envelope Stress Response Is Controlled by the Interaction of a Protein Binding Domain with Different Partners
The bacterial phage shock protein (Psp) system is a highly conserved cell envelope stress response required for virulence in Yersinia enterocolitica and Salmonella enterica. In non-inducing conditions the transcription factor PspF is inhibited by an interaction with PspA. In contrast, PspA associates with the cytoplasmic membrane proteins PspBC during inducing conditions. This has led to the proposal that PspBC exists in an OFF state, which cannot recruit PspA, or an ON state, which can. However, nothing was known about the difference between these two states.Transcriptional Regulation of the Daptomycin Gene Cluster in Streptomyces roseosporus by an Autoregulator, AtrA
Background: No investigation on daptomycin production at the transcriptional regulatory level has been reported.Results: The autoregulator AtrA directly regulates daptomycin gene cluster expression, and atrA is the transcriptional target of AdpA.Conclusion: The AtrA-mediated transcriptional signaling pathway directly regulates daptomycin production.Significance: We reveal for the first time the transcriptional regulatory mechanism of daptomycin production for its potential rational genetic engineering.Cross-talk between Two Nucleotide-signaling Pathways in Staphylococcus aureus
Nucleotide-signaling pathways are found in all kingdoms of life and are utilized to coordinate a rapid response to external stimuli. The stringent response alarmones guanosine tetra- (ppGpp) and pentaphosphate (pppGpp) control a global response allowing cells to adapt to starvation conditions such as amino acid depletion. One more recently discovered signaling nucleotide is the secondary messenger cyclic diadenosine monophosphate (c-di-AMP). Here, we demonstrate that this signaling nucleotide is essential for the growth of Staphylococcus aureus, and its increased production during late growth phases indicates that c-di-AMP controls processes that are important for the survival of cells in stationary phase.
