Axin, an inhibitor of the Wnt signalling pathway, interacts with β- catenin, GSK-3β and APC and reduces the β-catenin level

Abstract

Background: The Wnt/Wingless signalling pathway plays an important role in both embryonic development and tumorigenesis. β-Catenin and Axin are positive and negative effectors of the Wnt signalling pathway, respectively. Results: We found that Axin interacts with β-catenin and glycogen synthase kinase-3β (GSK-3β). Furthermore, the regulation of the G-protein signalling (RGS) domain of Axin is associated with the colorectal tumour suppressor adenomatous polyposis coli (APC). Overexpression of Axin in the human colorectal cancer cell line SW480 induced a drastic reduction in the level of β-catenin. Interaction with β-catenin and GSK-3β was required for the Axin-mediated β-catenin reduction. Conclusion: Axin interacts with β- catenin, GSK-3β and APC, and negatively regulates the Wnt signalling pathways, presumably by regulating the level of β-catenin.