Proteolysis of histidine kinase VgrS inhibits its autophosphorylation and promotes osmostress resistance in Xanthomonas campestris

Chao-Ying Deng,Li Wang,Ya-Jun Li,Yue Pan,Wei Qian,Shu-Tao Sun,Li-Li Ding,Yao Wu,Huan Zhang

doi:10.1038/s41467-018-07228-4

Abstract

In bacterial cells, histidine kinases (HKs) are receptors that monitor environmental and intracellular stimuli. HKs and their cognate response regulators constitute two-component signalling systems (TCSs) that modulate cellular homeostasis through reversible protein phosphorylation. Here the authors show that the plant pathogen Xanthomonas campestris pv. campestris responds to osmostress conditions by regulating the activity of a HK (VgrS) via irreversible, proteolytic modification. This regulation is mediated by a periplasmic, PDZ-domain-containing protease (Prc) that cleaves the N-terminal sensor region of VgrS. Cleavage of VgrS inhibits its autokinase activity and regulates the ability of the cognate response regulator (VgrR) to bind promoters of downstream genes, thus promoting bacterial adaptation to osmostress.

Highlights

In bacterial cells, histidine kinases (HKs) are receptors that monitor environmental and intracellular stimuli
When the bacterium is grown under osmolarity stress, Prc binds to a virulence-associated dipeptidyl peptidase (DppP)
Because HKs react to stimuli mainly through autophosphorylation and catalyse phosphoryl transfer to their cognate RRs, which control multiple cellular responses, regulation of the tempo and mode of HK phosphorylation is important for bacterial adaptation[31]

Summary

Introduction

Histidine kinases (HKs) are receptors that monitor environmental and intracellular stimuli. Campestris responds to osmostress conditions by regulating the activity of a HK (VgrS) via irreversible, proteolytic modification This regulation is mediated by a periplasmic, PDZ-domain-containing protease (Prc) that cleaves the N-terminal sensor region of VgrS. In gram-negative bacteria, regulated proteolysis catalysed by PDZ-domain-containing proteases, such as the HtrA-family proteases (high temperature requirement A) and tail-specific proteases (Tsp), modulates multiple physiological pathways, including virulence, stress response, quorum-sensing, protein quality control and antibiotic resistance[7,8]. These proteases are potential molecular targets for the development of novel antibacterial agents[9].

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Conclusion