Figure 4.
Basal MAPK cascade activity suppresses basal PI3K cascade activity in the Neuro-2A cell line. (A) Cells were pretreated for 45 minutes with the PI3K inhibitor, wortmannin (Wort), the MAPK inhibitor, U0126, the combination of wortmannin and U0126 or vehicle alone (0.43% DMSO). Cells were then treated an additional 15 minutes with the vehicle for IGF-1 (0.02mM HCl) to observe the effect of pretreatment alone on basal kinase activation. (B) Representative western blots of phosphorylated and total Akt (left) and ERK (right) developed with high-sensitivity chemiluminescent substrate after the indicated treatment paradigm. (C) Inhibition of MAPK with U0126 significantly increases basal phosphorylation of Akt. (D) Inhibition of PI3K/Akt with wortmannin has no effect on mean basal phosphorylation of ERK. Bar graphs represent mean value + SEM. + addition of drug, - omission of drug. *p<0.05 vs. DMSO pretreatment.