FIGURE 6.

siRNA depletion of BRAP, but not USP15, stimulates MEK phosphorylation in non-starved cells stimulated with a short pulse of EGF. A, HeLa cells were treated for 72 h with siRNA targeting KSR1, BRAP, USP4, or USP15 (oligo #17) and serum-starved for the last 16 h before stimulation with EGF (1 ng/ml) for 5 min. Knockdown efficiency as well as MEK and ERK phosphorylation were assessed by Western blotting (IB). B, cells were treated as in A but were not serum-starved. Graphs show results from four biological replicates (error bars, S.E., two-tailed paired t test compared with control; BRAP, p < 0.05; USP15: p < 0.01).