PR55α, a regulatory subunit of PP2A, specifically regulates PP2A-mediated β-catenin dephosphorylation

Wen Zhang, Jun Yang, Yajuan Liu, Xi Chen, Tianxin Yu, Jianhang Jia, Chunming Liu

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

A central question in Wnt signaling is the regulation of β-catenin phosphorylation and degradation. Multiple kinases, including CKIα and GSK3, are involved in β-catenin phosphorylation. Protein phosphatases such as PP2A and PP1 have been implicated in the regulation of β-catenin. However, which phosphatase dephosphorylates β-catenin in vivo and how the specificity of β-catenin dephosphorylation is regulated are not clear. In this study, we show that PP2A regulates β-catenin phosphorylation and degradation in vivo. We demonstrate that PP2A is required for Wnt/β-catenin signaling in Drosophila. Moreover, we have identified PR55α as the regulatory subunit of PP2A that controls β-catenin phosphorylation and degradation. PR55α, but not the catalytic subunit, PP2Ac, directly interacts with β-catenin. RNA interference knockdown of PR55α elevates β-catenin phosphorylation and decreases Wnt signaling, whereas overexpressing PR55α enhances Wnt signaling. Taken together, our results suggest that PR55α specifically regulates PP2A-mediated β-catenin dephosphorylation and plays an essential role in Wnt signaling.

Original languageEnglish (US)
Pages (from-to)22649-22656
Number of pages8
JournalJournal of Biological Chemistry
Volume284
Issue number34
DOIs
StatePublished - Aug 21 2009

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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