Figure 4.
Small tumor antigen (ST) interacts with PP2A in Drosophila embryos. (a) PP2AC co-immunoprecipitates (co-IP) with ST-FLAG, but poorly with ST PP2A-binding mutants STC103S and STΔPP2A. Western blotting of lysates shows that ST-FLAG and mutant derivatives are expressed at similar levels, except for STΔPP2A-FLAG, which is approximately 1.8-fold higher than the others. α-Tubulin was used as a loading control. PP2AC co-IPs with ST-FLAG and STD44N-FLAG. A reduced amount of PP2AC co-IPs with STC103S-FLAG, and none is detected with STΔPP2A-FLAG. (b) ST-FLAG co-IPs with PP2AC from embryo lysates.