Substrate recognition mechanism of atypical protein kinase Cs revealed by the structure of PKCι in complex with a substrate peptide from Par-3

Structure. 2012 May 9;20(5):791-801. doi: 10.1016/j.str.2012.02.022.


Protein kinase C (PKC) play critical roles in many cellular functions including differentiation, proliferation, growth, and survival. However, the molecular bases governing PKC's substrate recognitions remain poorly understood. Here we determined the structure of PKCι in complex with a peptide from Par-3 at 2.4 Å. PKCι in the complex adopts catalytically competent, closed conformation without phosphorylation of Thr402 in the activation loop. The Par-3 peptide binds to an elongated groove formed by the N- and C-lobes of the kinase domain. The PKCι/Par-3 complex structure, together with extensive biochemical studies, reveals a set of substrate recognition sites common to all PKC isozymes as well as a hydrophobic pocket unique to aPKC. A consensus aPKC's substrate recognition sequence pattern can be readily identified based on the complex structure. Finally, we demonstrate that the pseudosubstrate sequence of PKCι resembles its substrate sequence, directly binds to and inhibits the activity of the kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Cell Adhesion Molecules / chemistry*
  • Cell Adhesion Molecules / metabolism
  • HEK293 Cells
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Isoenzymes / chemistry
  • Isoenzymes / metabolism
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • Peptides / chemistry*
  • Peptides / metabolism
  • Phosphorylation
  • Protein Kinase C / chemistry*
  • Protein Kinase C / metabolism
  • Protein Structure, Tertiary
  • Substrate Specificity
  • Transfection


  • Cell Adhesion Molecules
  • Isoenzymes
  • Pard3 protein, mouse
  • Peptides
  • Protein Kinase C