EMSA of NF-κB activity in pepstatin-treated cells.

(A) Nuclear extracts were prepared from cells treated with CD40L in the presence of pepstatin A for 45 minutes and NF-κB DNA binding activity was determined. The arrowhead indicates the position of the protein-DNA complex. (B) Quantitation of the effect of pepstatin A on CD40-mediated NF-κB activation. Data shown are mean ± SE from 3 independent experiments performed as in panel C. Pep indicates pepstatin A.