FIG. 3.
Inhibition of Dvl-induced JNK activation by CKIɛ. 293 cells were cotransfected with the HA-tagged JNK expression construct with Flag-tagged Dvl expression constructs and Myc-tagged CKIɛ expression constructs. CKIɛ KF mutant contains a K38F mutation in the kinase domain and lacks kinase activity. As a control for activation of JNK by an alternative mechanism, cells were treated with UV at 40 J/m2 before cell harvesting. HA-tagged JNK was immunoprecipitated by anti-HA antibodies, and the abilities of JNK to phosphorylate GST-c-Jun were determined. The results were visualized with a PhosphorImager (top panel). The expression of Dvl and CKIɛ was confirmed by immunoblotting with anti-Flag and anti-Myc antibodies (bottom panels).