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Glycogen synthase kinase-3 beta mutagenesis identifies a common binding domain for GBP and Axin

Denise M Ferkey1, David Kimelman

  • 1Department of Biochemistry and Center for Developmental Biology, University of Washington, Seattle, Washington 98195-7350, USA.

The Journal of Biological Chemistry
|February 28, 2002
PubMed

Insights

Glycogen synthase kinase-3 beta (GSK-3) binding proteins Axin and GBP compete for the same site. Mutations altering this interaction affect GSK-3

Area of Science:

  • Molecular Biology
  • Developmental Biology
  • Biochemistry

Background:

  • Glycogen synthase kinase-3 beta (GSK-3) is a crucial Wnt signaling pathway target.
  • GSK-3 activity is modulated by interactions with activating (Axin) and inhibitory (GBP/FRAT) proteins.
  • Protein binding competition regulates GSK-3 activity on non-primed substrates.

Purpose of the Study:

  • Identify GSK-3 mutations affecting GBP and Axin binding using a reverse two-hybrid screen.
  • Investigate the functional consequences of these mutations on GSK-3 activity and developmental processes.
  • Determine if GSK-3 regulates Xenopus eye development via Wnt-dependent or independent pathways.

Main Methods:

  • Reverse two-hybrid screening to identify GSK-3 binding mutants.
  • Biochemical assays to confirm altered binding affinities.
  • Xenopus embryo manipulation to assess developmental roles.

Main Results:

  • Identified overlapping mutations in GSK-3 that alter binding to both GBP and Axin.
  • Mutations suggest GBP and Axin compete for the same binding region on GSK-3.
  • GSK-3 mutations impact Xenopus eye development, indicating a non-Wnt pathway involvement.

Conclusions:

  • GSK-3, Axin, and GBP interact at a common binding site.
  • GSK-3 plays a role in Xenopus eye development independent of the Wnt pathway.
  • Understanding GSK-3 binding dynamics offers insights into developmental regulation.

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