DksA–DnaJ redox interactions provide a signal for the activation of bacterial RNA polymerase

Abstract

Significance Transcription in Gram-negative bacteria is greatly influenced by the synergistic interactions of DksA and the nucleotide alarmone guanosine tetraphosphate. Our investigations reveal a unique, previously unknown layer of transcriptional regulation that depends on redox-based protein–protein interactions between DksA and the molecular chaperone DnaJ. Tripartite connections between DksA, DnaJ, and guanosine tetraphosphate afford a dynamic range of transcriptional responses to H 2 O 2 concentrations associated with redox signaling or oxidative stress. The redox-based gene regulation dependent on the combined actions of DksA, DnaJ, and guanosine tetraphosphate confers resistance of Salmonella to the antimicrobial activity of the NADPH phagocyte oxidase.