B MEF-Cuedc2-/- cells were transfected with increasing amounts of FLAG-CUEDC2 (mouse) plasmids (1 μg and 2 μg). At 24 hours after transfection, the cells were treated with the proteasome inhibitor MG-132 (10 μM). Cells were cultured for additional 6 hours and subjected to immunoblotting. 