Figure 7.

Relative effects of proteasome-associated DUBs on proteasome structure and function. Soluble extracts were prepared from HeLa cells treated for 3 d with siRNA of the indicated subunits. Extracts, 550–700 μg, were subjected to glycerol density gradient centrifugation, and collected fractions were assayed for Suc-Leu-Leu-Val-Tyr-AMC hydrolyzing activity (left panel) or were separated using SDS-PAGE probed with the indicated antibodies. Shown gradients were obtained from separate centrifugations due to limited capacity of the centrifuge. However, multiple blots for each RNAi target were conducted with samples from the same gradient. Results were qualitatively similar for each profile in at least three independent experiments.