Fig. 9. Western analysis of mutant VHA55 expression levels in yeast. Mutant vma2 yeast were grown under selective (Met^-), but pH-permissive (pH 5) conditions, and vacuoles harvested and analysed by western blot with anti-VHA55 antibody. Yeast contained plasmids containing either vha55::GFP, or vha55::GFP with the point mutations corresponding to those described in Fig. 1.