Figure 5.

Inhibition of 26S proteasomes by depletion of the 19S RP subunit PSMD1 triggers NOXA-dependent apoptosis. (a) Apoptosis induced by depletion of different 19S RP subunits correlates with high endogenous NOXA levels. HeLa cells were transfected with siRNA pools of the indicated 19S RP subunits or a control siRNA (10 nM each) for 48 h and apoptosis quantified (top panel). Results are the means ±S.E.M. (n=3). Indicated endogenous proteins were assessed by immunoblotting (lower panel). (b) HeLa or (c) H1299 cells were transfected with a pool of PSMD1 siRNAs, and either a control or pool of NOXA siRNAs (10 nM) from Dharmacon (NOXA #1) or Ambion (NOXA #2). After 48 h, apoptosis was quantified (top panels). Results are the means ±S.E.M. (n=3). The levels of indicated proteins were assessed by immunoblotting (lower panels)