Regulation of beta-catenin signaling by the B56 subunit of protein phosphatase 2A.
Dysregulation of Wnt-beta-catenin signaling disrupts axis formation in vertebrate embryos and underlies multiple human malignancies. The adenomatous polyposis coli (APC) protein, axin, and glycogen synthase kinase 3beta form a Wnt-regulated signaling complex that mediates the phosphorylation-dependent degradation of beta-catenin. A protein phosphatase 2A (PP2A) regulatory subunit, B56, interacted with APC in the yeast two-hybrid system. Expression of B56 reduced the abundance of beta-catenin and inhibited transcription of beta-catenin target genes in mammalian cells and Xenopus embryo explants. The B56-dependent decrease in beta-catenin was blocked by oncogenic mutations in beta-catenin or APC, and by proteasome inhibitors. B56 may direct PP2A to dephosphorylate specific components of the APC-dependent signaling complex and thereby inhibit Wnt signaling.
Duke Scholars
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Related Subject Headings
- beta Catenin
- Zebrafish Proteins
- Xenopus Proteins
- Xenopus
- Wnt Proteins
- Tumor Cells, Cultured
- Transfection
- Transcriptional Activation
- Trans-Activators
- Signal Transduction
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- beta Catenin
- Zebrafish Proteins
- Xenopus Proteins
- Xenopus
- Wnt Proteins
- Tumor Cells, Cultured
- Transfection
- Transcriptional Activation
- Trans-Activators
- Signal Transduction