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Updated: Aug 11, 2026

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Reconstitution Of β-catenin Degradation In Xenopus Egg Extract
Published on: June 18, 2014
beta-catenin can be transported into the nucleus in a Ran-unassisted manner
F Yokoya1, N Imamoto, T Tachibana
1Department of Anatomy and Cell Biology, Osaka University Medical School, Osaka 565-0871, Japan. yyoneda@anat3.med.osaka-u.ac.jp
Molecular Biology of the Cell
|April 10, 1999
Summary
Beta-catenin, crucial for Wingless/Wnt signaling, enters the nucleus independently of Ran GTP. This study reveals beta-catenin
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Beta-catenin is vital for the Wingless/Wnt signaling pathway.
- Nuclear accumulation of beta-catenin regulates gene expression.
- Understanding beta-catenin's nuclear transport is key to Wnt pathway modulation.
Purpose of the Study:
- To investigate the mechanism of nuclear import of beta-catenin in mammalian cells.
- To determine if beta-catenin nuclear import is dependent on the Ran GTPase cycle.
- To elucidate the regulation of nuclear beta-catenin levels.
Main Methods:
- Microinjection of beta-catenin into cytoplasm of living mammalian cells.
- In vitro nuclear import assays using semi-intact cells.
- Utilizing temperature-sensitive mutant cell lines (tsBN2) and mutant Ran.
Main Results:
- Beta-catenin rapidly translocates into the nucleus in a temperature-dependent manner.
- Nuclear import occurs independently of cytosol, Ran, or GTP/ATP.
- Import is insensitive to Ran-GTP depletion, indicating a Ran-unassisted mechanism.
- Beta-catenin also rapidly exits the nucleus in homokaryons.
Conclusions:
- Beta-catenin possesses intrinsic machinery for constitutive nuclear translocation via nuclear pores.
- Nuclear import of beta-catenin is Ran-independent, unlike many other nuclear proteins.
- Regulation of nuclear beta-catenin involves both import and export processes.
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