Dishevelled-1 DIX and PDZ domain lysine residues regulate oncogenic Wnt signaling

Abstract

DVL proteins are central mediators of the Wnt pathway and relay complex input signals into different branches of the Wnt signaling network. However, molecular mechanism(s) that regulate DVL-mediated relay of Wnt signals still remains unclear. Here, for the first time, we elucidate the functional significance of three DVL-1 lysines (K/Lys) which are subject to post-translational acetylation. We demonstrate that K34 Lys residue in the DIX domain regulates subcellular localization of β-catenin, thereby influencing downstream Wnt target gene expression. Additionally, we show that K69 (DIX domain) and K285 (PDZ domain) regulate binding of DVL-1 to Wnt target gene promoters and modulate expression of Wnt target genes including CMYC, OCT4, NANOG, and CCND1, in cell line models and xenograft tumors. Finally, we report that conserved DVL-1 lysines modulate various oncogenic functions such as cell migration, proliferation, cell-cycle progression, 3D-spheroid formation and in-vivo tumor growth in breast cancer models. Collectively, these findings highlight the importance of DVL-1 domain-specific lysines which were recently shown to be acetylated and characterize their influence on Wnt signaling. These site-specific modifications may be subject to regulation by therapeutics already in clinical use (lysine deacetylase inhibitors such as Panobinostat and Vorinostat) or may possibly have prognostic utility in translational efforts that seek to modulate dysfunctional Wnt signaling.