Recognition of an intra-chain tandem 14-3-3 binding site within PKCepsilon

EMBO Rep. 2009 Sep;10(9):983-9. doi: 10.1038/embor.2009.150. Epub 2009 Aug 7.

Abstract

The phosphoserine/threonine binding protein 14-3-3 stimulates the catalytic activity of protein kinase C-epsilon (PKCepsilon) by engaging two tandem phosphoserine-containing motifs located between the PKCepsilon regulatory and catalytic domains (V3 region). Interaction between 14-3-3 and this region of PKCepsilon is essential for the completion of cytokinesis. Here, we report the crystal structure of 14-3-3zeta bound to a synthetic diphosphorylated PKCepsilon V3 region revealing how a consensus 14-3-3 site and a divergent 14-3-3 site cooperate to bind to 14-3-3 and so activate PKCepsilon. Thermodynamic data show a markedly enhanced binding affinity for two-site phosphopeptides over single-site 14-3-3 binding motifs and identifies Ser 368 as a gatekeeper phosphorylation site in this physiologically relevant 14-3-3 ligand. This dual-site intra-chain recognition has implications for other 14-3-3 targets, which seem to have only a single 14-3-3 motif, as other lower affinity and cryptic 14-3-3 gatekeeper sites might exist.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / chemistry*
  • 14-3-3 Proteins / metabolism*
  • Amino Acid Sequence
  • Binding Sites
  • Cell Line
  • Crystallography, X-Ray
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Phosphoserine / metabolism
  • Protein Binding
  • Protein Kinase C-epsilon / chemistry*
  • Protein Kinase C-epsilon / metabolism*
  • Protein Structure, Quaternary
  • Thermodynamics

Substances

  • 14-3-3 Proteins
  • Phosphoserine
  • Protein Kinase C-epsilon