Forced expression of ubiquitin does not prevent IDOL induction by DUB inhibition.
A, HepG2 or HepG2-FLAG ubiquitin cells were treated with control or 25 μm MG132 for 2 h. Total cell lysates were immunoblotted as indicated. B, HepG2-FLAG-ubiquitin cells were treated with vehicle (control), 25 μm MG132, 5 μm HBX41-108, or 50 μm PR-619 for 2 h. Subsequently, mRNA expression of Idol was determined by qPCR. Each bar represents the mean ± S.D. relative to vehicle-treated control cells (n = 3). ***, p < 0.001. UB, ubiquitin.