Cdk-5 stimulation of AAH and Humbug expression is mediated by signaling through Erk MAPK and PI3 kinase: SH-Sy5y cells were transfected with recombinant plasmids to over-express Luciferase or Cdk-5+p25. 36 hours after transfection, the cells were treated with vehicle (Con), PD98059 (PD9), or LY294002 (LY2). 12 hours later, i.e. 48 hours after transfection, the cells were harvested to measure (A) AAH, (B) Humbug, or (C) Junctin mRNA levels by real time quantitative RT-PCR. The graphs depict the mean ± S.D. of results normalized to 18S rRNA measured in the same samples. Statistical comparisons were made using ANOVA with post hoc Fisher LSD tests (*P < 0.001 relative to corresponding vehicle-treated control).