A Two-Component Regulatory System in Transcriptional Control of Photosystem Stoichiometry: Redox-Dependent and Sodium Ion-Dependent Phosphoryl Transfer from Cyanobacterial Histidine Kinase Hik2 to Response Regulators Rrel and RppA

作者：Ibrahim Iskander M; Puthiyaveetil Sujith; Allen John F^*

来源：Frontiers in Plant Science, 2016, 7: 137.

DOI：10.3389/fpls.2016.00137

• redox sensor
• redox regulator
• photosystem stoichiometry
• transcriptional control
• Histidine Kinase 2
• Chloroplast Sensor Kinase (CSK)
• Synechocystis sp PCC 6803
• salt stress

Two-component systems (TCSs) are ubiquitous signaling units found in prokaryotes. A TCS consists of a sensor histidine kinase and a response regulator protein as signal transducers. These regulatory systems mediate acclimation to various environmental changes by coupling environmental cues to gene expression. Hik2 is a sensor histidine kinase and its gene is found in all cyanobacteria. Hik2 is the homolog of Chloroplast Sensor Kinase (CSK), a protein involved in redox regulation of chloroplast gene expression during changes in light quality in plants and algae. Here we describe biochemical characterization of the signaling mechanism of Hik2 and its phosphotransferase activity. Results presented here indicate that Hik2 undergoes autophosphorylation on a conserved histidine residue, and becomes rapidly dephosphorylated by the action of response regulators Rrel and RppA. We also show that the autophosphorylation of Hik2 is specifically inhibited by sodium ions.

• 出版日期2016-2-12