BAFF-induced phosphorylation of p38MAPK, AKT, IκBα, and PKCθ depends on BAFF-R triggering. Mock-treated B cells were incubated for 30 minutes at 4°C with medium or 10 μg/mL anti–BAFF-R Ab and then stimulated with medium or 50 ng/mL BAFF. The p52 contents of total-cell lysates were corrected for actin content. Phosphorylation of AKT, IΚBα, p38MAPK, classical PKC, and PKCθ were each corrected for total relevant protein. Blots from one representative experiment are shown. Values reported for p52 contents and phosphorylation are mean values plus or minus SD from 2 independent experiments.