Fig. 2. Rap1 levels during growth of the pVEII-AS5'-1 transformant in the absence of folate. Cells were harvested at the day indicated following the removal of folate, and the total cellular protein was fractionated by SDS-PAGE. Rap1 levels were determined by western blot analysis using a Dictyostelium Rap1-specific antibody. The RasG levels were determined with a RasG-specific antibody.