3.5 ISX9 inhibits the association of Axin1 with β-catenin
Axin is a vital component in the β-catenin destruction complex, which provides a scaffold for recruitment of GSK3β, CK1α, and β-catenin, facilitating the phosphorylation and degradation of β-catenin. We therefore examined the effect of ISX9 binding to Axin1 on the interaction of Axin1 and β-catenin. An immunoprecipitation assay was performed in HEK293T cells. As seen in Figure S2, treatment with ISX9 dramatically inhibited the interaction between Axin and β-catenin, but had little effect on the association of β-catenin with GSK3β (Supplementary Figure S2). These results indicated that ISX9 binding to Axin1 could facilitate the release Axin1 from the β-catenin destruction complex.