Figure 2.

IκBa degradation in B-1a and B2 cells in the presence or absence of phosphatase inhibition. Sorted B-1a and B-2 cells were pre-treated for 1 h with cycloheximide (50 μM). Afterward, cells were either treated with or without anit-IgM (15 μg/ml) for 30 or 90 min, as indicated, or cells were cultured with 2 mM sodium orthovanadate (Na₃VO₄) for 15 min and then treated with anti-IgM for 30 or 90 min. Cells were collected, supernatants discarded, and pellets frozen at −20°C until lysed in NP-40 lysis buffer and used for western blot analysis of IκBα. Results shown are representative of two independent experiments.