Fig. 4

Fig. 4 LiaS acts primarily as a phosphatase or inhibitor of LiaR phosphorylation.

A The luc reporter gene was placed under the control of the promoter of spv_0803, a gene that is strongly induced by LiaR-P. Upon bacitracin (BAC) treatment, luciferase was highly expressed, indicating induction of the LiaR regulon. Deletion of liaS results in overexpression of luciferase. A ∆liaF mutant displays slight induction of the LiaR regulon, even in the absence of BAC. B A phosphomimetic version of LiaR (LiaR*, D53E) was constructed under the control of the IPTG-inducible P_lac promoter. The strain P_{spv_0803}-luc, P_lac-liaR* phenocopied a ∆liaS mutant in both growth phenotype and induction of the regulon. C Activation of the LiaR regulon by expression of LiaR* results in increased sensitivity to ciprofloxacin (CIP). Growth curve data represent the mean ± SEM of three biological replicates. Source data are provided as a Source Data file.