Cs+ induces the kdp operon of Escherichia coli by lowering the intracellular K+ concentration

Cs+ mas found to induce expression of the kdpFABC operon, encoding a high-affinity K+ uptake system of Escherichia coli. Quantitative expression analyses at the transcriptional and translational levels reveal that CsCI causes much higher induction of kdpFABC than does NaCl. A decrease of the intracellular K+ concentration is found in cells exposed to CsCI. The results indicate that kdpFABC expression is induced when the intracellular K+ concentration is lowered. Moreover, the results imply that the signal transduction cascade mediated by KdpD and KdpE is able to integrate multiple signals.