Related Experiment Video

Updated: Sep 28, 2026

Reconstitution Of β-catenin Degradation In Xenopus Egg Extract
09:41

Reconstitution Of β-catenin Degradation In Xenopus Egg Extract

Published on: June 17, 2014

Domains of axin involved in protein-protein interactions, Wnt pathway inhibition, and intracellular localization

F Fagotto1, E h Jho, L Zeng

  • 1Division of Cell Biology, Max-Planck Institute for Developmental Biology, 72076 Tübingen, Germany.

The Journal of Cell Biology
|May 20, 1999
PubMed

Insights

Axin protein regulates embryonic axis formation by inhibiting Wnt signaling. Key domains for its function involve binding to GSK3beta and APC, crucial for beta-catenin regulation.

Area of Science:

  • Developmental Biology
  • Molecular Biology
  • Cell Signaling

Background:

  • Axin is a key regulator of embryonic axis induction in vertebrates.
  • It functions within the Wnt signal transduction pathway, inhibiting its activity.
  • Axin forms a complex with glycogen synthase kinase 3beta (GSK3beta), beta-catenin, and adenomatous polyposis coli (APC).

Purpose of the Study:

  • To investigate the specific roles of different Axin protein domains in embryonic axis formation.
  • To determine how Axin domains influence beta-catenin levels and Wnt signaling.
  • To understand the localization patterns of Axin and its interactions with other signaling proteins.

Main Methods:

  • Epistasis experiments in frog embryos.
  • Analysis of Axin domain function through protein interaction studies.
  • Coexpression of tagged Axin and Dishevelled (Dsh) proteins to study localization and interaction.

Main Results:

  • The regulators of G-protein signaling (RGS) domain and GSK3beta-binding site of Axin are essential for its function.
  • COOH-terminal sequences, including the protein phosphatase 2A (PP2A) binding site and DIX domain, are not critical.
  • Axin lacking a direct beta-catenin binding site can still regulate beta-catenin levels and axis formation indirectly.
  • NH2-terminal sequences are required for Axin localization, while COOH-terminal sequences enhance spot localization.
  • Dishevelled (Dsh) colocalizes with Axin, suggesting interaction with the Axin/APC/GSK3/beta-catenin complex.

Conclusions:

  • Interaction with APC and GSK3beta is critical for Axin's regulation of beta-catenin signaling in embryonic cells.
  • Specific Axin domains dictate its role in axis formation and protein complex formation.
  • Axin localization is dependent on its N-terminal sequences, with C-terminal sequences influencing specific localization patterns.
  • Dishevelled may modulate the activity of the Axin/APC/GSK3/beta-catenin complex through direct interaction.

More Related Videos

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients08:10

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

Published on: December 14, 2015

Modeling Paracrine Noncanonical Wnt Signaling In Vitro11:14

Modeling Paracrine Noncanonical Wnt Signaling In Vitro

Published on: December 10, 2021

Related Concept Videos

Generation of Straight or Branched Actin Filaments01:14

Generation of Straight or Branched Actin Filaments

The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
Non-Canonical Wnt Signaling Pathways01:41

Non-Canonical Wnt Signaling Pathways

Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
Non-Canonical Wnt Signaling Pathways01:41

Non-Canonical Wnt Signaling Pathways

Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...
Catenins01:23

Catenins

Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...