ExpSup: CagA Activates β-catenin in Tyrosine-phosphorylation Independent Manner

β-catenin is usually present in the plasma membrane at cell-cell junctions in a complex called adherens junction. Upon activation, β-catenin is released from the membrane and moves to the cell nucleus, and activates transcription of several genes that have β-catenin binding sites. β-catenin has also been shown to be degraded in the cytoplasm by APC protein.

Murata-Kamiya et al., 2007 showed activation of beta-catenin in the presence of both wild-type and phospho-resistant CagA mutant by luciferase reporter assay. Furthermore, they showed that the coexpression of APC protein significantly reduces the luciferase activity.

In addition, they showed that CagA ectopic expression in MKN-28 and MKN-45 cells results in nuclear accumulation of β-catenin

Cell line: MKN-28 and MKN-45
Plasmid construct: Wild-type CagA and tyrosine phospho-resistant CagA mutant
Methods: Immunocytochemistry and Luciferase reporter assay using constructs that contain β-catenin signal or mutated β-catenin signal

REFERENCES:

Murata-Kamiya et al., 2007. Helicobacter pylori CagA interacts with E-cadherin and deregulates the beta-catenin signal that promotes intestinal transdifferentiation in gastric epithelial cells. Oncogene. 26(32), 4617-4626. PMID-17237808; Full Text Links: Nature

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