Fig. 7

Wnt pathway APC/CTNNB1 nuclear model known and proposed. Known nuclear model: A For nuclear CTNNB1 degradation, both APC anchored with AXIN [46] binds to CTNNB1 along with SOX17 [20] and marks it for ubiquitin degradation. B When CTNNB1 enters the nucleus, it could proceed and bind transcription factors TCF7 [47], JUN, and FOSL1 [9] to initiate cell proliferation. Proposed nuclear model: C When CTNNB1 enters the nucleus, it could be inhibited through APC binding to TCF7, FOSL1, and JUN transcription factors. D For nuclear CTNNB1 degradation, APC, AXIN1, and SOX17 bind to CTNNB1. However, this might require the binding of SOX17 to both CTNNB1 (known) and APC (novel) to mark CTNNB1 for ubiquitin degradation. Green pathway (known); red pathway (a proposed mechanism)