ClpP modulates the activity of the Bacillus subtilis stress response transcription factor, σB

Adam Reeves, Ulf Gerth, Uwe Völker, W. G. Haldenwang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The general stress regulon of Bacillus subtilis is controlled by the activity state of σB, a transcription factor that is switched on following exposure to either physical or nutritional stress. ClpP is the proteolytic component of an ATP-dependent protease that is essential for the proper regulation of multiple adaptive responses in B. subtilis. Among the proteins whose abundance increases in ClpP- B. subtilis are several known to depend on σB for their expression. In the current work we examine the relationship of ClpP to the activity of σB. The data reveal that the loss of ClpP in otherwise wild-type B. subtilis results in a small increase in σB activity during growth and a marked enhancement of σB activity following its induction by either physical or nutritional stress. It appears to be the persistence of σB,s activity rather than its induction that is principally affected by the loss of ClpP. σB-dependent reporter gene activity rose in parallel in ClpP+ and ClpP- B. subtilis strains but failed to display its normal transience in the ClpP- strain. The putative ClpP targets are likely to be stress generated and novel. Enhanced σB activity in ClpP- B. subtilis was triggered by physical stress but not by the induced synthesis of the physical stress pathway's positive regulator (RsbT). In addition, Western blot analyses failed to detect differences in the levels of the principal known σB regulators in ClpP+ and ClpP- B. subtilis strains. The data suggest a model in which ClpP facilitates the turnover of stress-generated factors, which persist in ClpP's absence to stimulate ongoing σB activity.

Original languageEnglish (US)
Pages (from-to)6168-6175
Number of pages8
JournalJournal of bacteriology
Volume189
Issue number17
DOIs
StatePublished - Sep 2007

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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