Molecular mimicry regulates ABA signaling by SnRK2 kinases and PP2C phosphatases

Science. 2012 Jan 6;335(6064):85-8. doi: 10.1126/science.1215106. Epub 2011 Nov 24.

Abstract

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.

Publication types

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

MeSH terms

  • Abscisic Acid / chemistry
  • Abscisic Acid / metabolism*
  • Amino Acid Sequence
  • Arabidopsis / chemistry
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / antagonists & inhibitors
  • Arabidopsis Proteins / chemistry*
  • Arabidopsis Proteins / metabolism*
  • Catalytic Domain
  • Crystallography, X-Ray
  • Enzyme Activation
  • Models, Molecular
  • Molecular Mimicry*
  • Molecular Sequence Data
  • Phosphoprotein Phosphatases / chemistry*
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / chemistry*
  • Protein-Serine-Threonine Kinases / metabolism*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction

Substances

  • Arabidopsis Proteins
  • PYL2 protein, Arabidopsis
  • Recombinant Fusion Proteins
  • SnRK2 protein, Arabidopsis
  • Abscisic Acid
  • Protein-Serine-Threonine Kinases
  • ABI2 protein, Arabidopsis
  • HAB1 protein, Arabidopsis
  • Phosphoprotein Phosphatases

Associated data

  • PDB/3UJG
  • PDB/3UJK
  • PDB/3UJL