Periplasmic peptidyl-prolyl isomerases SurA and FkpA play an important role in the starvation-stress response (SSR) of Salmonella enterica serovar Typhimurium

Antonie Van Leeuwenhoek. 2010 Jun;98(1):51-63. doi: 10.1007/s10482-010-9428-2. Epub 2010 Mar 17.

Abstract

Carbon-energy source (C)-starved cells of Salmonella enterica serovar Typhimurium (S. Typhimurium) are remarkably more resistant to stress than actively growing ones. Carbon-starved S. Typhimurium is capable of withstanding extended periods of starvation and assault from a number of different stresses that rapidly kill growing cells. These unique properties of the C-starved cell are the direct result of a series of genetic and physiological adaptations referred to as the starvation-stress response (SSR). Previous work established that the SSR of S. Typhimurium is partially regulated by the extracytoplasmic function sigma factor sigma(E). As part of an effort to identify sigma(E)-regulated SSR genes, we investigated surA and fkpA, encoding two different classes of peptidyl-prolyl isomerase that function in folding cell envelope proteins. Both surA and fkpA are members of the heat-shock-inducible sigma(E) regulon of Escherichia coli. Although both genes are expressed in C-starved Salmonella cells, evidence indicates that surA and fkpA are not C-starvation-inducible. Furthermore, their expression during C-starvation does not appear to be sigma(E)-dependent. Nonetheless, surA and fkpA proved to be important, to differing degrees, for long-term C-starvation survival and for the cross-resistance of C-starved cells to high temperature, acidic pH, and the antimicrobial peptide polymyxin B, but neither were required for cross-resistance to oxidative stress. These results point to fundamental differences between heat-shock-inducible and C-starvation-inducible genes regulated by sigma(E) and suggest that genes other than surA and fkpA are involved in the sigma(E)-regulated branch of the SSR in Salmonella.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acids / toxicity
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / metabolism*
  • Carbon / metabolism
  • Gene Expression Regulation, Bacterial
  • Hot Temperature
  • Peptidylprolyl Isomerase / metabolism*
  • Polymyxin B / pharmacology
  • Regulon
  • Salmonella typhimurium / drug effects
  • Salmonella typhimurium / metabolism
  • Salmonella typhimurium / physiology*
  • Salmonella typhimurium / radiation effects
  • Sigma Factor / metabolism
  • Stress, Physiological*

Substances

  • Acids
  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Sigma Factor
  • sporulation-specific sigma factors
  • Carbon
  • Peptidylprolyl Isomerase
  • Polymyxin B