The Wnt signaling pathway is conserved in various species from worms to mammals, and plays important roles in cellular proliferation, differentiation, and migration. Wnt stabilizes cytoplasmic beta-catenin and then the accumulated beta-catenin is translocated into the nucleus, where it activates the transcriptional factor T-cell factor (Tcf)/lymphoid enhancer factor (Lef), and thereby stimulates the expression of genes including c-myc, c-jun, fra-1, and cyclin D1. Tight regulation of this response involves post-translational modifications of the components of the Wnt signaling pathway. Phosphorylation, ubiquitination, and sumoylation have been shown to affect the half-life of beta-catenin and the transcriptional activity of Tcf/Lef. The precise spatio-temporal patterns of these multiple modifications determine the driving force of various cellular responses.
Animals ; Binding Sites ; Gene Expression Regulation ; Humans ; Models, Biological ; Protein Binding ; *Protein Processing, Post-Translational ; *Signal Transduction ; TCF Transcription Factors ; *Trans-Activators ; Wnt Proteins/classification/genetics/*metabolism ; beta Catenin