E3 ubiquitin-protein ligase which catalyzes the formation of 'Lys-48'-polyubiquitin chains. Mediates the ubiquitination and subsequent degradation of phosphorylated Akt (AKT1, AKT2 and AKT3 in the nucleus. Acts as a terminal regulator of Akt signaling after activation; its phosphorylation by Akt, which is a prerequisite for ubiquitin ligase activity, suggests the existence of a regulation mechanism required to control Akt levels after activation. Positively regulates TGFB1-induced epithelial-mesenchymal transition and myofibroblast differentiation by mediating the ubiquitination and subsequent degradation of SMURF2. Regulates neuronal differentiation by regulating actin remodeling and Golgi organization via a signaling cascade involving RHOA, CIT and ROCK. Inhibits cell proliferation.