FIG. 2.

Proteasome inhibitors block degradation of IκB-α induced by LPS in RAW 264.7 cells. (A) Cells were incubated with 1 μg of LPS per ml for the indicated times and lysed for Western blotting with antibodies against IκB-α. (B) Proteasome inhibitors were incubated with cells for 30 min before LPS was added for a further 30-min incubation. Cells were then lysed for Western blotting with antibodies against IκB-α. These blots showed a single immunoreactive band of approximately 40 kDa, corresponding to IκB-α, and only this portion of the blot is shown. Results are representative of three independent experiments.