Fig. 7. Specificity of the inhibition of NF-B-dependent activation by NaSal. COS cells were cotransfected with plasmids expressing wild-type or activated (75L) TC10 (A and B), wild-type or activated (61L) Cdc42 (A), or a constitutively active MEKK1 (B) and a reporter plasmid containing NF-B binding elements fused to a firefly luciferase gene. Six h posttransfection, cells were maintained in serum-free medium for 20 h and then transferred to fresh serum-free medium in the absence (-) or presence (+) of 1 mM acetaminophen (A) or 5 µM indomethacin (B) for 6 h. Cells were then harvested, lysed, and examined for luciferase expression. The columns represent the average percentage of activation relative to TC10 75L (for TC10 and TC10 75L samples), Cdc42 61L (for Cdc42 and Cdc42 61L samples), or MEKK1 (for MEKK1 samples) in the absence of drug treatment for two experiments, and the error bars show the range. The level of GTPase or MEKK1 expression was determined by immunoblotting to be similar for all samples.