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Connecting two-component regulatory systems by a protein that protects a response regulator from dephosphorylation by

Akinori Kato1, Eduardo A Groisman

  • 1Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

Genes & Development
|September 17, 2004
PubMed

Insights

Salmonella

Area of Science:

  • Microbiology
  • Molecular Biology
  • Signal Transduction

Background:

  • Two-component systems (TCS) are crucial for bacterial signal transduction.
  • Integrating signals from different TCS is vital for cellular responses.

Purpose of the Study:

  • To elucidate the mechanism of Salmonella's PmrA/PmrB TCS responding to the PhoP/PhoQ TCS signal.
  • To identify how PmrD protein influences PmrA activity.

Main Methods:

  • Investigated protein-protein interactions between PmrD, PmrA, and PmrB.
  • Assessed the impact of PmrD on PmrA phosphorylation and dephosphorylation.
  • Analyzed PmrA-mediated gene transcription.

Main Results:

  • PhoP-activated PmrD binds to phosphorylated PmrA, inhibiting its dephosphorylation.
  • Phosphorylated PmrA exhibits higher affinity for target promoters, driving transcription.
  • A PmrD-independent PmrA variant resisted dephosphorylation, activating genes without induction.

Conclusions:

  • PmrD acts as a molecular link, allowing the PmrA/PmrB TCS to sense signals from the PhoP/PhoQ TCS.
  • This mechanism represents a novel way for bacteria to integrate environmental cues via distinct two-component systems.

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