Recognition and integration of multiple environmental signals by the bacterial sensor kinase PhoQ.

Two-component regulatory systems are commonly used by bacteria to sense and respond to their environment. In Molecular Cell, Prost et al. describe how low pH activates the Salmonella PhoQ sensor kinase, building on their previous demonstration that the PhoQ periplasmic domain senses magnesium and antimicrobial peptides. These findings are likely to be broadly applicable for understanding how bacteria recognize and transduce the multiple signals characteristic of their complex extracellular environments.