Figure 1.

Stability of the 100-kD V-ATPase subunit (Vph1p) in wild-type and vma mutant cells. Cells were pulse labeled with [³⁵S]methionine for 10 min and chased in the presence of 50 mM unlabeled methionine. Samples were removed at 0, 30, 60, and 90 min during the chase, denaturing cell extracts prepared, and Vph1p was immunoprecipitated using polyclonal sera. Immunoprecipitated proteins were separated by SDS-PAGE, dried gels were exposed to a phosphor screen, and data was collected using a phosphorimaging system. WT, wild-type.