Unveiling the Coordinated action of DesK/DesR and YvfT/YvfU to control
the expression of an ABC transporter in Bacillus subtilis .
Abstract
Two-component systems (TCSs) are vital signal transduction pathways
ubiquitous among bacteria, facilitating their responses to diverse
environmental stimuli. In Bacillus subtilis, the DesK histidine
kinase thermosensor, together with the response regulator DesR,
constitute a TCS dedicated to membrane lipid homeostasis maintenance.
This TCS orchestrates the transcriptional regulation of the des
gene, encoding the sole desaturase in these bacteria, Δ5-Des.
Additionally, B. subtilis possesses a paralog TCS, YvfT/YvfU,
with unknown target gene(s). In this work we show that YvfT/YvfU
controls the expression of the yvfRS operon that codes for an ABC
transporter. Interestingly, we found that this regulation also involves
the action of DesK/DesR. Notably, opposite to des, yvfRS
transcription is induced at 37°C and not at 25°C. Our in vivo and
in vitro experiments demonstrate that both YvfU and DesR directly
bind to the operon promoter region, with DesR exerting its control over
yvfRS expression in its unphosphorylated state. Our study
uncovers an intriguing case of cross-regulation where two homologous
TCSs interact closely to finely tune gene expression in response to
environmental cues. These findings shed light on the complexity of
bacterial signal transduction systems and their critical role in
bacterial adaptability.