Acetylation of conserved DVL-1 lysines regulates its nuclear translocation and binding to gene promoters in triple-negative breast cancer

Monica Sharma,Isabel Castro-Piedras,Kevin Pruitt,Deborah Molehin,Edgar G Martinez

doi:10.1038/s41598-019-52723-3

Monica Sharma, Isabel Castro-Piedras + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-52723-3

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Abstract

Dishevelled (DVL) proteins are central mediators of the Wnt signalling pathway and are versatile regulators of several cellular processes, yet little is known about their post-translational regulation. Acetylation is a reversible post-translational modification (PTM) which regulates the function of several non-histone proteins involved in tumorigenesis. Since we previously demonstrated that lysine deacetylase, SIRT-1, regulates DVL protein levels and its function, we reasoned that DVL could potentially be a substrate for SIRT-1 mediated deacetylation. To further examine the potential role of multiple families of lysine deacetylases in the post-translational regulation of DVL, we screened for novel acetylation sites using liquid chromatography mass-spectrometry (LC-MS/MS) analysis. Herein, we report 12 DVL-1 lysine residues that show differential acetylation in response to changes in oxygen tension and deacetylase inhibition in triple-negative breast cancer (TNBC). PTMs are well documented to influence protein activity, and cellular localization. We also identify that acetylation of two key lysine residues, K69 and K285, present on the DIX and PDZ domains respectively, promote nuclear over cytoplasmic localization of DVL-1, and influences its promoter binding and regulation of genes implicated in cancer. Collectively, these findings for the first time, uncover acetylation as a novel layer of regulation of DVL-1 proteins.

Highlights

Dishevelled (DVL) proteins are central mediators of the Wnt signalling pathway and are versatile regulators of several cellular processes, yet little is known about their post-translational regulation
We found that DVL-1 mRNA levels did not vary considerably among the six cell lines (Figs 1A and S1A)
We found that levels of DVL-1 proteins were relatively higher in triple-negative cells like MDA-MB-231, MDA-MB-468 and BT-549 cells compared to normal tissue lysates (NT) and hormone-receptor (ER/PR+) positive breast cancer cell lines (Figs 1B and S1B)

Summary

Introduction

Dishevelled (DVL) proteins are central mediators of the Wnt signalling pathway and are versatile regulators of several cellular processes, yet little is known about their post-translational regulation. We identify that acetylation of two key lysine residues, K69 and K285, present on the DIX and PDZ domains respectively, promote nuclear over cytoplasmic localization of DVL-1, and influences its promoter binding and regulation of genes implicated in cancer. These findings for the first time, uncover acetylation as a novel layer of regulation of DVL-1 proteins. For the first time, we report acetylation of 12 lysine residues present on conserved domains of DVL-1 protein, in response to oxygen tension and deacetylase inhibition in TNBC cells. This study is the first to reveal a novel mode of DVL regulation and reports acetylation as a novel driver of DVL-1 nuclear translocation and suggests that acetylation may influence DVL’s role as a transcriptional regulator

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