PKC-δ inhibitor rottlerin abrogates IFN-α-induced phosphorylation of PKC-δ. Daudi cells pretreated with 1 μM rottlerin for 1 h were stimulated with 1,000 U/ml IFN-α for 6 h, followed by assays for levels of phospho-PKC-δ and phospho-JNK (A). Arrows indicate specific bands for pPKC-δ, PKC-δ, pJNK, JNK1, and Actin, respectively. †, non-specific band. Results are expressed as relative expression: phospho-PKC or phospho-JNK levels normalized to actin levels with the indicated stimulators are divided by phospho-PKC-δ or phospho-JNK levels normalized to actin levels without stimulation (B). Each point represents mean ± SD from three independent experiments (B&C). *Significantly different (p < 0.05) from control without inhibitor.