Fig. 7. chm deletions in yeast cannot sort a CPS-GFP fusion protein to the vacuole lumen. Parental yeast (+) and the indicated chm mutants were transformed with a GFP-CPS expression vector (2 µm). Each strain was stained with the vital dye FM4-64 (red), which labels the vacuolar membrane under our chase conditions, and was imaged by laser scanning confocal microscopy. Rescue of chm1 is shown with a single copy plasmid containing the ADH promoter fused to the CHM1 open reading frame. Note the lumenal GFP signal in the parent and the CHM1/chm1 strain, but membrane localization in all chm mutants. The strong GFP signal that accumulates adjacent to the vacuole in all chm mutants marks apparent class E compartments.