Effect of IL-3 deprivation on PKC overexpression in  and δ TF-1 transfectants. Cell lines overexpressing PKC or PKCδ were grown in the absence or presence of IL-3 (10 ng/mL) for 40 hours. At the end of incubation, lysates were prepared and equal amounts of protein were analyzed by electrophoresis in the same polyacrylamide gel. Immunoblot analysis was performed with an  isoform specific polyclonal antibody that recognized the 12 amino acid  epitope. Thus both PKC and PKCδ with the  epitope tag could be detected in the same immunoblot. Relative levels of  and δ overexpression were directly compared in the immunoblot by digitizing the immunoblot image and analyzing with the 1D Gel Scan program (Scanalytics).