The Axin scaffold protects the kinase GSK3β from cross-pathway inhibition

  1. Maire Gavagan
  2. Noel Jameson
  3. Jesse G Zalatan  Is a corresponding author
  1. University of Washington, United States

Abstract

Multiple signaling pathways regulate the kinase GSK3β by inhibitory phosphorylation at Ser9, which then occupies the GSK3β priming pocket and blocks substrate binding. Since this mechanism should affect GSK3β activity towards all primed substrates, it is unclear why Ser9 phosphorylation does not affect other GSK3β-dependent pathways, such as Wnt signaling. We used biochemical reconstitution and cell culture assays to evaluate how Wnt-associated GSK3β is insulated from cross-activation by other signals. We found that the Wnt-specific scaffold protein Axin allosterically protects GSK3β from phosphorylation at Ser9 by upstream kinases, which prevents accumulation of pS9-GSK3β in the Axin-GSK3β complex. Scaffold proteins that protect bound proteins from alternative pathway reactions could provide a general mechanism to insulate signaling pathways from improper crosstalk.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting file; Source Data files have been provided for Figures 2-4 and supplemental figures.

Article and author information

Author details

  1. Maire Gavagan

    Department of Chemistry, University of Washington, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3986-6760
  2. Noel Jameson

    Department of Chemistry, University of Washington, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Jesse G Zalatan

    Department of Chemistry, University of Washington, Seattle, United States
    For correspondence
    zalatan@uw.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1458-0654

Funding

National Institutes of Health (R35 GM124773)

  • Maire Gavagan
  • Noel Jameson
  • Jesse G Zalatan

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2023, Gavagan et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 862
    views
  • 116
    downloads
  • 6
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Maire Gavagan
  2. Noel Jameson
  3. Jesse G Zalatan
(2023)
The Axin scaffold protects the kinase GSK3β from cross-pathway inhibition
eLife 12:e85444.
https://doi.org/10.7554/eLife.85444

Share this article

https://doi.org/10.7554/eLife.85444

Further reading

    1. Biochemistry and Chemical Biology
    2. Microbiology and Infectious Disease
    Flavia A Zanetti, Ignacio Fernandez ... Laura Ruth Delgui
    Research Article

    Birnaviruses are a group of double-stranded RNA (dsRNA) viruses infecting birds, fish, and insects. Early endosomes (EE) constitute the platform for viral replication. Here, we study the mechanism of birnaviral targeting of EE membranes. Using the Infectious Bursal Disease Virus (IBDV) as a model, we validate that the viral protein 3 (VP3) binds to phosphatidylinositol-3-phosphate (PI3P) present in EE membranes. We identify the domain of VP3 involved in PI3P-binding, named P2 and localized in the core of VP3, and establish the critical role of the arginine at position 200 (R200), conserved among all known birnaviruses. Mutating R200 abolishes viral replication. Moreover, we propose a two-stage modular mechanism for VP3 association with EE. Firstly, the carboxy-terminal region of VP3 adsorbs on the membrane, and then the VP3 core reinforces the membrane engagement by specifically binding PI3P through its P2 domain, additionally promoting PI3P accumulation.

    1. Biochemistry and Chemical Biology
    2. Microbiology and Infectious Disease
    Stephanie M Stuteley, Ghader Bashiri
    Insight

    In the bacterium M. smegmatis, an enzyme called MftG allows the cofactor mycofactocin to transfer electrons released during ethanol metabolism to the electron transport chain.