McsB Is a Protein Arginine Kinase That Phosphorylates and Inhibits the Heat-Shock Regulator CtsR

Abstract

Transcriptional Repressor Dissected Living organisms have quality-control mechanisms to eliminate proteins damaged by environmental stresses. In the model organism Bacillus subtilis , the transcriptional repressor CtsR controls the expression of genes that are key to the heat-shock response. CtsR is activated by the kinase McsB to allow transcription of stress response genes, however, the mechanism of activation is unclear. Fuhrmann et al. (p. 1323 ) now describe structural and biochemical studies showing that McsB inhibits DNA binding of CtsR by specifically phosphorylating arginine residues in its DNA binding domain. This study provides a basis for exploring a potential wider role of arginine phosphorylation in prokaryotic and eukaryotic transcriptional regulation.