Inverse regulatory coordination of motility and curli-mediated adhesion in Escherichia coli

Genes Dev. 2008 Sep 1;22(17):2434-46. doi: 10.1101/gad.475808.

Abstract

During the transition from post-exponential to stationary phase, Escherichia coli changes from the motile-planktonic to the adhesive-sedentary "lifestyle." We demonstrate this transition to be controlled by mutual inhibition of the FlhDC/motility and sigma(S)/adhesion control cascades at two distinct hierarchical levels. At the top level, motility gene expression and the general stress response are inversely coordinated by sigma(70)/sigma(FliA)/sigma(S) competition for core RNA polymerase and the FlhDC-controlled FliZ protein acting as a sigma(S) inhibitor. At a lower level, the signaling molecule bis-(3'-5')-cyclic-diguanosine monophosphate (c-di-GMP) reduces flagellar activity and stimulates transcription of csgD, which encodes an essential activator of adhesive curli fimbriae expression. This c-di-GMP is antagonistically controlled by sigma(S)-regulated GGDEF proteins (mainly YegE) and YhjH, an EAL protein and c-di-GMP phosphodiesterase under FlhDC/FliA control. The switch from motility-based foraging to the general stress response and curli expression requires sigma(S)-modulated down-regulation of expression of the flagellar regulatory cascade as well as proteolysis of the flagellar master regulator FlhDC. Control of YhjH by FlhDC and of YegE by sigma(S) produces a fine-tuned checkpoint system that "unlocks" curli expression only after down-regulation of flagellar gene expression. In summary, these data reveal the logic and sequence of molecular events underlying the motile-to-adhesive "lifestyle" switch in E. coli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclic GMP / analogs & derivatives
  • Cyclic GMP / physiology
  • Escherichia coli K12 / physiology*
  • Escherichia coli Proteins / metabolism
  • Fimbriae, Bacterial / physiology*
  • Flagella / physiology*
  • Gene Expression Regulation, Bacterial
  • Phosphoric Diester Hydrolases / metabolism
  • Trans-Activators / metabolism

Substances

  • CsgD protein, E coli
  • Escherichia coli Proteins
  • Trans-Activators
  • YhjH protein, E coli
  • flhC protein, E coli
  • flhD protein, E coli
  • bis(3',5')-cyclic diguanylic acid
  • Phosphoric Diester Hydrolases
  • Cyclic GMP