AKT1 and neoplasm: Another possible explanation to the lack of tumor suppressor proteolysis in SKP2/N-RasV12 and SKP2/myr-AKT1 mice is that overexpression of SKP2 alone is not sufficient to trigger an effective ubiquitinylation program in the mouse liver and, presumably, some other SKP2 partners require to be concomitantly overexpressed to achieve this goal.