Structural basis for recruitment of glycogen synthase kinase 3beta to the axin-APC scaffold complex

EMBO J. 2003 Feb 3;22(3):494-501. doi: 10.1093/emboj/cdg068.

Abstract

Glycogen synthase kinase 3beta (GSK3beta) is a serine/threonine kinase involved in insulin, growth factor and Wnt signalling. In Wnt signalling, GSK3beta is recruited to a multiprotein complex via interaction with axin, where it hyperphosphorylates beta-catenin, marking it for ubiquitylation and destruction. We have now determined the crystal structure of GSK3beta in complex with a minimal GSK3beta-binding segment of axin, at 2.4 A resolution. The structure confirms the co-localization of the binding sites for axin and FRAT in the C-terminal domain of GSK3beta, but reveals significant differences in the interactions made by axin and FRAT, mediated by conformational plasticity of the 285-299 loop in GSK3beta. Detailed comparison of the axin and FRAT GSK3beta complexes allows the generation of highly specific mutations, which abrogate binding of one or the other. Quantitative analysis suggests that the interaction of GSK3beta with the axin scaffold enhances phosphorylation of beta-catenin by >20 000-fold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenomatous Polyposis Coli Protein / chemistry
  • Adenomatous Polyposis Coli Protein / metabolism*
  • Axin Protein
  • Binding Sites
  • Carrier Proteins*
  • Cell Line
  • Crystallography, X-Ray
  • Cytoskeletal Proteins / metabolism
  • Glycogen Synthase Kinase 3 / chemistry*
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Structure
  • Multiprotein Complexes
  • Mutation
  • Neoplasm Proteins*
  • Phosphorylation
  • Protein Structure, Tertiary*
  • Proteins / chemistry*
  • Proteins / metabolism
  • Proto-Oncogene Proteins / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Repressor Proteins*
  • Signal Transduction / physiology*
  • Trans-Activators / metabolism
  • Tyrosine / metabolism
  • Wnt Proteins
  • Zebrafish Proteins*
  • beta Catenin

Substances

  • Adenomatous Polyposis Coli Protein
  • Axin Protein
  • CTNNB1 protein, human
  • Carrier Proteins
  • Cytoskeletal Proteins
  • FRAT1 protein, human
  • Intracellular Signaling Peptides and Proteins
  • Macromolecular Substances
  • Multiprotein Complexes
  • Neoplasm Proteins
  • Proteins
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • Trans-Activators
  • Wnt Proteins
  • Zebrafish Proteins
  • beta Catenin
  • Tyrosine
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3