Wnt-dependent regulation of the E-cadherin repressor snail.
Down-regulation of E-cadherin marks the initiation of the epithelial-mesenchymal transition, a process exploited by invasive cancer cells. The zinc finger transcription factor, Snail, functions as a potent repressor of E-cadherin expression that can, acting alone or in concert with the Wnt/beta-catenin/T cell factor axis, induce an epithelial-mesenchymal transition. Although mechanisms that coordinate signaling events initiated by Snail and Wnt remain undefined, we demonstrate that Snail displays beta-catenin-like canonical motifs that support its GSK3beta-dependent phosphorylation, beta-TrCP-directed ubiquitination, and proteasomal degradation. Accordingly, Wnt signaling inhibits Snail phosphorylation and consequently increases Snail protein levels and activity while driving an in vivo epithelial-mesenchymal transition that is suppressed following Snail knockdown. These findings define a potential mechanism whereby Wnt signaling stabilizes Snail and beta-catenin proteins in tandem fashion so as to cooperatively engage transcriptional programs that control an epithelial-mesenchymal transition.
PubMed ID: 15647282
Article link: J Biol Chem.
Grant support: R01 CA071699 NCI NIH HHS , R01 CA085463 NCI NIH HHS , R01 CA088308 NCI NIH HHS
Genes referenced: btrc cdh1 gsk3b snai1
Antibodies referenced: Btrc Ab1