Fig. 7. yck^ts cells show wild-type processing of the vacuolar protein ALP. Wild-type (WT), apm3, yck^ts and yck^ts apm3- cells were grown to exponential growth phase at 24°C, then washed and resuspended at the same density in fresh medium depleted of inorganic phosphate for three hours at 37°C. Protein extracts prepared from wild-type and mutant cells were analyzed by SDS-PAGE and western immunoblotting for ALP. We used as a control strains sec7, defective in intra-Golgi trafficking at the non-permissive temperature, and pep4, defective in vacuolar protease processing. Pep4p-dependent cleavage of pro-ALP (pro) results in the formation of mature ALP (m) and a small amount of the aberrant form of ALP (*). The mature form of ALP is formed in sec7 mutants during growth at the permissive temperature.