Figure 4

ATRA suppresses the auto-phosphorylation of KIT and AKT protein but not MAPK activity. Panel A shows the suppression of KIT and AKT activity after 2-, 4- or 6-day treatment with 180 μM ATRA. Panel B shows the suppression of KIT and AKT activity after 4 hours treatment with different ATRA concentrations in serum-free media. The results demonstrated that KIT and AKT activity were suppressed by ATRA treatment in a dose- and time-dependent manner but not MAPK activity.