Two-component signaling circuit structure and properties

Abstract

Various modeling and experimental studies have analyzed the reactions, interconnections, and motifs in two-component systems, with an eye toward understanding their physiological implications and the differences between alternative designs. Examples where recent progress has been made include aspects of autoregulation, signal integration in branched pathways, cross-talk suppression, and cross-regulation via connector proteins.

Fig. 1

Three different architectures that extend two-component systems beyond simple linear pathways A) One-to-many branched pathway. One histidine kinase phosphorylates two response regulators. B) Many-to-one branched pathway. Two histidine kinases phosphorylate the same response regulator. C) Connector-mediated pathway. The HK1/RR1 two-component system activates expression of a connector protein X, which modulates the activity of the HK2/RR2 system. X may act on the histidine kinase or response regulator and may increase or decrease RR2 phosphorylation.