The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+ Sensing and Agr Signaling to Infection Programming

摘要

The Kdp system is widely distributed among bacteria. In Escherichia coli, the Kdp-ATPase is a high-affinity K⁺ uptake system and its expression is activated by the KdpDE two-component system in response to K⁺ limitation or salt stress. However, information about the role of this system in many bacteria still remains obscure. Here we demonstrate that KdpFABC in Staphylococcus aureus is not a major K⁺ transporter and that the main function of KdpDE is not associated with K⁺ transport but that instead it regulates transcription for a series of virulence factors through sensing external K⁺ concentrations, indicating that this bacterium might modulate its infectious status through sensing specific external K⁺ stimuli in different environments. Our results further reveal that S. aureus KdpDE is upregulated by the Agr/RNAIII system, which suggests that KdpDE may be an important virulence regulator coordinating the external K⁺ sensing and Agr signaling during pathogenesis in this bacterium.