Figure 4.
Dominant-negative versions of MEK do not block Raf-mediated NF-κB activation. (A) Transient transfection of Jurkat cells with the 3xκB.luc reporter and expression vectors for active Raf (BXB-CX), wild-type IKK-2, and the two dominant-negative versions of MEK (MEK-S217A and MEK-K97 M, 15 μg each). (B) IKK-2 stimulation by active Raf (BXB-CX) is not inhibited by dominant-negative MEK (MEK-S217A). Jurkat T cells were transfected with the indicated plasmids as before. (Upper) An autoradiograph of an immune complex assay of IKK-2 activity using IκBα as a substrate. The band marked with an asterisk represents autophosphorylated IKK-2. Numbers indicate relative IKK-2 kinase activity. (Lower) Control immunoblot of immunoprecipitated IKK-2.