Control of Snail1 protein stability by post-translational modifications: the basis for a complex regulation of Snail1 function.

Snail1 transcriptional factor is essential for the epithelial to mesenchymal transition and for the acquisition by tumor cells of properties associated to this transition, such as increased invasion and chemoresistance. Snail1 function is mainly controlled post-translationally, through different modifications that directly or indirectly control Snail1 protein stability. In this review I describe these modifications, the enzymes that produce them and their relevance for Snail1 function, focusing particularly in polyubiquitination and phosphorylation. I also propose several explanations for the divergent effects of some of these modifications, since the phosphorylation of some residues have been reported to both promote and decrease Snail1 stability. Moreover, I discuss the possible causes of the observed Snail1 promiscuity in the interaction with the many factors involved in its regulation, on the basis of the proposed Snail1 structure.