Figure 3.

DYRK1A acts synergistically with Ras, B-Raf, and MEK1 to increase ERK-dependent Elk1 activation. PC12 cells were cotransfected with 1 μg of 5x-Gal4-TATA/luciferase, 70 ng of Gal4-Elk1 (Elk/gal), 1 μg of CMV-βGal, and the indicated expression plasmids. Cells were serum starved for 20 h and stimulated with 100 ng/ml NGF for 6 h before being collected (48 h posttransfection). Activation of Elk1 is reflected by luciferase activity normalized to βGal activity and is described as fold increase. Error bars represent means ± SEM. For comparisons indicated by brackets, three asterisks indicate a p value <0.0001. Values obtained with DYRK1A and DYRK1A-K188R were not significantly different (p > 0.05).