AKT1 and cancer: Phosphorylation of β-catenin in many cell types such as cancer cells results in its proteolytic degradation.32 Although a portion of the phosphorylated β-catenin undergoes proteolytic degradation in Akt1-deficient endothelial cells, these cells still have enough of phosphorylated β-catenin to translocate to the nucleus and function as a transcription repressor for claudins.