The uPA-MP construct responds to the MEKK and MEK1 kinases in LNCaP cells. LNCaP cells, transfected with reporter plasmids as for Figure 1, were cotransfected with increasing amounts of plasmids constitutively expressing MEKK or MEK1. As in Figure 1, the uPA-MP reporter construct shows a significant dose-dependent response to the cotransfected MEKK (A) and MEK1 (B). Error bars indicate SD. (C-D) Quantitation of the data in panels A and B, respectively, is as in Figure 1.