PC12 neuronal differentiation involves p53 stabilization and activation. A) Immunoblot depicting total and phospho-serine 15 p53 protein levels over time following 50 ng/mL NGF 2.5S, with total actin protein levels serving as loading control. B) RT-PCR levels of p53 mRNA over time following NGF 2.5S treatment compared to β-actin loading control. C) Luciferase activity in PC12 cells transfected with p53TAluc reporter vector following NGF 2.5S treatment at indicated time intervals, where p ≤ 0.05. Error bars represent standard deviation.