Transforming activity of CBL mutants. 32D cells or 32Ds overexpressing wild-type FLT3 were transfected with wild-type or mutant CBL constructs and assayed for IL-3 independent growth over 3 days. Results shown are the mean of at least 3 independent experiments, each of which were performed in triplicate. The y-axis shows proliferation in arbitrary units as determined by MTS assay (Promega) and the x-axis time in days.