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- Title
GSK3β Is Involved in JNK2-Mediated β-Catenin Inhibition.
- Authors
Dong Hu; Xiuli Bi; Wenfeng Fang; Anjia Han; Wancai Yang
- Abstract
Background: We have recently reported that mitogen-activated protein kinase (MAPK) JNK1 downregulates β-catenin signaling and plays a critical role in regulating intestinal homeostasis and in suppressing tumor formation. This study was designed to determine whether JNK2, another MAPK, has similar and/or different functions in the regulation of β-catenin signaling. Methodology and Principal Findings: We used an in vitro system with manipulation of JNK2 and β-catenin expression and found that activated JNK2 increased GSK3β activity and inhibited β-catenin expression and transcriptional activity. However, JNK2-mediated downregulation of β-catenin was blocked by the proteasome inhibitor MG132 and GSK3β inhibitor lithium chloride. Moreover, targeted mutations at GSK3β phosphorylation sites (Ser33 and Ser37) of β-catenin abrogated JNK2- mediated suppression of β-catenin. In vivo studies further revealed that JNK2 deficiency led to upregulation of β-catenin and increase of GSK3-β phosphorylation in JNK2-/- mouse intestinal epithelial cells. Additionally, physical interaction and colocalization among JNK2, β-catenin and GSK3β were observed by immunoprecipitation, mammalian two-hybridization assay and confocal microscopy, respectively. Conclusion and Significance: In general, our data suggested that JNK2, like JNK1, interacts with and suppresses β-catenin signaling in vitro and in vivo, in which GSK3β plays a key role, although previous studies have shown distinct functions of JNK1 and JNK2. Our study also provides a novel insight into the crosstalk between Wnt/β-catenin and MAPK JNKs signaling.
- Subjects
MITOGEN-activated protein kinases; HOMEOSTASIS; GENETIC transcription; PHOSPHORYLATION; BOTANICAL microscopy; PROTEIN kinases; PHYSIOLOGICAL control systems; TRANSCRIPTION factors
- Publication
PLoS ONE, 2009, Vol 4, Issue 8, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0006640