Cs + Induces the kdp Operon of Escherichia coli by Lowering the Intracellular K + Concentration

Abstract
Cs + was 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 CsCl causes much higher induction of kdpFABC than does NaCl. A decrease of the intracellular K + concentration is found in cells exposed to CsCl. 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.