(D) BN-PAGE of BAK and BAK-Ub on liposomes following incubation with 4 µM BID-BH3 peptide in the presence or absence of 25 mM TCEP, immunoblotted for BAK. Data representative of three independent experiments. Graphs shows densitometric analysis of the BAK tetramer (4x) from three or two independent experiments. Error bars represent mean +/- SD for n=3 or mean and range for n=2. 