Figure 4.
KCTD10 promotes ubiquitination and degradation of β-catenin through the K48-ubiquitin chain. (A) Co-IP analysis demonstrating the interaction between KCTD10 and β-catenin proteins. (B) Representative schematic of KCTD10 and β-catenin protein domains. (C, D) Identification of the interacting regions between truncated KCTD10 and β-catenin proteins. (E) Degradation of β-catenin proteins after CHX treatment. (F) Effect of KCTD10 on β-catenin protein stability in the presence of MG132. (G, H) Fluorescence analysis and Western blots showing KCTD10-induced degradation of cytoplasmic β-catenin. (I–K) KCTD10 overexpression enhanced the ubiquitination of β-catenin. Myc-β-catenin was immunoprecipitated with rabbit polyclonal anti-β-catenin antibodies and these immunocomplexes were subjected to Western blotting with anti-ubiquitin antibodies to detect β-catenin-ubiquitin conjugates. In the ubiquitin constructs, R indicates that the corresponding lysine residue has been mutated to arginine, abolishing linkage at that site; O indicates that only the corresponding lysine residue remains intact, while all other lysines are mutated, allowing selective assessment of linkage through that specific site.
