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Structural requirements for Yersinia YopJ inhibition of MAP kinase pathways

Yi-Heng Hao1, Yong Wang, Dara Burdette

  • 1Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA.

Plos One
|January 3, 2008
PubMed

Insights

Bacterial effector YopJ inhibits mitogen-activated protein kinase (MAPK) signaling via acetylation. Suppressor mutations in yeast Pbs2 revealed a conserved binding site, demonstrating functional conservation between yeast and human MAPK kinases.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Microbial Pathogenesis

Background:

  • Mitogen-activated protein kinase (MAPK) signaling pathways are crucial, evolutionarily conserved cellular processes.
  • Bacterial effector YopJ inhibits MAPK activation through a unique Ser/Thr acetylation mechanism, impacting both yeast and human pathways.

Purpose of the Study:

  • To identify yeast MAPK kinase (MKK) mutants that suppress YopJ-mediated inhibition.
  • To elucidate the molecular basis of YopJ interaction with MKKs and identify conserved inhibition mechanisms.

Main Methods:

  • Genetic screening of yeast Pbs2 (an MKK) to isolate YopJ-resistant mutants.
  • Site-directed mutagenesis of conserved residues in yeast and human MKKs.
  • Biochemical assays to assess kinase activity, binding, and acetylation.

Main Results:

  • A suppressor mutant with a mutation in a conserved tyrosine residue was identified, increasing Pbs2 basal activity.
  • Mutations on the hydrophobic face of the MKK kinase domain's G alpha-helix blocked YopJ binding and acetylation.
  • Human MKK mutants exhibited conserved structural and functional responses to these mutations, mirroring yeast findings.

Conclusions:

  • A conserved binding site for YopJ exists on the superfamily of MAPK kinases.
  • Specific mutations within the kinase domain can confer resistance to YopJ inhibition by altering enzyme activity or YopJ interaction.
  • These findings highlight conserved molecular interactions governing YopJ inhibition across species.

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