Nuclear Dvl, c-Jun, β-catenin, and TCF form a complex leading to stabiLization of β-catenin–TCF interaction

In canonical Wnt signaling, Dishevelled (Dvl) is a critical cytoplasmic regulator that releases β-catenin from degradation. Here, we find that Dvl and c-Jun form a complex with β-catenin–T-cell factor 4 (TCF-4) on the promoter of Wnt target genes and regulate gene transcription. The complex forms via two interactions of nuclear Dvl with c-Jun and β-catenin, respectively, both of which bind to TCF. Disrupting the interaction of Dvl with either c-Jun or β-catenin suppresses canonical Wnt signaling–stimulated transcription, and the reduction of Dvl diminished β-catenin–TCF-4 association on Wnt target gene promoters in vivo. Expression of a TCF-Dvl fusion protein largely rescued the c-Jun knockdown Wnt signaling deficiency in mammalian cells and zebrafish. Thus, we confirm that c-Jun functions in canonical Wnt signaling and show that c-Jun functions as a scaffold in the β-catenin–TCFs transcription complex bridging Dvl to TCF. Our results reveal a mechanism by which nuclear Dvl cooperates with c-Jun to regulate gene transcription stimulated by the canonical Wnt signaling pathway.