Inhibition of NFκB activity by NS protease and proteasome inhibitors. Cells were incubated for 6 hours in the absence (control) or presence of 25 μmol/L zAPFcmk or 10 μmol/L MG132, and NFκB activity was measured in isolated nuclear extracts by EMSA using an NFκB consensus element DNA probe. Lane 1, control extracts with excess unlabeled probe (specificity control); lane 2, 6 hours control; lane 3, zAPFcmk; lane 4, MG-132. Results of one experiment typical of over 20 independent replicates.