FUNCTIONAL INTERACTION OF AN AXIN HOMOLOG, CONDUCTIN, WITH BETA-CATENIN, APC, AND GSK3-BETA

Control of stability of beta-catenin is central in the wnt signaling p athway. Here, the protein conductin was found to form a complex with b oth beta-catenin and the tumor suppressor gene product adenomatous pol yposis coli (APC), Conductin induced beta-catenin degradation, whereas mutants of conductin that were deficient in complex formation stabili zed beta-catenin. Fragments of APC that contained a conductin-binding domain also blocked beta-catenin degradation. Thus, conductin is a com ponent of the multiprotein complex that directs beta-catenin to degrad ation and is located downstream of APC. In Xenopus embryos, conductin interfered with wnt-induced axis formation.