Identification of a major determinant for serine-threonine kinase phosphoacceptor specificity

Mol Cell. 2014 Jan 9;53(1):140-7. doi: 10.1016/j.molcel.2013.11.013. Epub 2013 Dec 26.

Abstract

Eukaryotic protein kinases are generally classified as being either tyrosine or serine-threonine specific. Though not evident from inspection of their primary sequences, many serine-threonine kinases display a significant preference for serine or threonine as the phosphoacceptor residue. Here we show that a residue located in the kinase activation segment, which we term the "DFG+1" residue, acts as a major determinant for serine-threonine phosphorylation site specificity. Mutation of this residue was sufficient to switch the phosphorylation site preference for multiple kinases, including the serine-specific kinase PAK4 and the threonine-specific kinase MST4. Kinetic analysis of peptide substrate phosphorylation and crystal structures of PAK4-peptide complexes suggested that phosphoacceptor residue preference is not mediated by stronger binding of the favored substrate. Rather, favored kinase-phosphoacceptor combinations likely promote a conformation optimal for catalysis. Understanding the rules governing kinase phosphoacceptor preference allows kinases to be classified as serine or threonine specific based on their sequence.

Publication types

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

MeSH terms

  • Binding Sites
  • Crystallography, X-Ray
  • HEK293 Cells
  • Humans
  • Kinetics
  • Peptides / chemistry*
  • Peptides / genetics
  • Peptides / metabolism
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / chemistry*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Substrate Specificity / physiology
  • p21-Activated Kinases / chemistry*
  • p21-Activated Kinases / genetics
  • p21-Activated Kinases / metabolism

Substances

  • Peptides
  • MST4 protein, human
  • PAK4 protein, human
  • Protein-Serine-Threonine Kinases
  • p21-Activated Kinases

Associated data

  • PDB/2Q0N
  • PDB/4JDH
  • PDB/4JDI
  • PDB/4JDJ
  • PDB/4JDK