FIG. 5.

Disassembly of the V-ATPase in mutant strains. (A and B) Yeast vph1Δ stv1Δ cells containing the vph1-E789Q allele (A) or a wild-type copy of the gene (B) in a low-copy-number plasmid were converted to spheroplasts and radiolabeled as described in Materials and Methods. Labeled spheroplasts were chased for 30 min in YEPD (position 1), 20 min in YEP (position 2), or 20 min in YEP, followed by an additional 10 min with 2% glucose added (position 3). (C) Yeast vma11Δ cells containing the vma11-E145L allele in a low-copy-number plasmid were converted to spheroplasts and chased as described for panels A and B. Immunoprecipitations were performed and analyzed as described for Fig. 2. The bars represent the average of two independent experiments in panels A and C and results from a single measurement in panel B. Error bars indicate the range of the two experiments. Disassembly and reassembly of the 100-, 36-, and 17-kDa subunits were measured in each experiment and are shown individually, as indicated.