Structural basis of GSK-3 inhibition by N-terminal phosphorylation and by the Wnt receptor LRP6

Elife. 2014 Mar 18;3:e01998. doi: 10.7554/eLife.01998.

Abstract

Glycogen synthase kinase-3 (GSK-3) is a key regulator of many cellular signaling pathways. Unlike most kinases, GSK-3 is controlled by inhibition rather than by specific activation. In the insulin and several other signaling pathways, phosphorylation of a serine present in a conserved sequence near the amino terminus of GSK-3 generates an auto-inhibitory peptide. In contrast, Wnt/β-catenin signal transduction requires phosphorylation of Ser/Pro rich sequences present in the Wnt co-receptors LRP5/6, and these motifs inhibit GSK-3 activity. We present crystal structures of GSK-3 bound to its phosphorylated N-terminus and to two of the phosphorylated LRP6 motifs. A conserved loop unique to GSK-3 undergoes a dramatic conformational change that clamps the bound pseudo-substrate peptides, and reveals the mechanism of primed substrate recognition. The structures rationalize target sequence preferences and suggest avenues for the design of inhibitors selective for a subset of pathways regulated by GSK-3. DOI: http://dx.doi.org/10.7554/eLife.01998.001.

Keywords: GSK-3; LRP6; Wnt signaling; protein kinase.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Catalysis
  • Crystallography, X-Ray
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors*
  • Glycogen Synthase Kinase 3 / chemistry
  • Glycogen Synthase Kinase 3 / metabolism
  • Humans
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • Substrate Specificity

Substances

  • Glycogen Synthase Kinase 3