Fig. 7. Dnm1p and Vps1p have distinct functions. Dnm1p overexpression does not restore the vacuolar fusion defect in vps1 cells, and Vps1p overexpression does not rescue the mitochondrial fission defect in dnm1 cells. (A) Vacuoles were visualised by allowing cells to take up FM4-64 to steady-state levels. The vacuolar membrane is clearly visible in wild-type (WT) cells and in vps1 cells expressing Vps1p, whereas unfused, fragmented vacuoles are visible in vps1 cells and in vps1 cells overexpressing Dnm1p. (B) Cells expressing mito-GFP were grown to log phase on 2% glucose. dnm1 cells overexpressing Vps1p show the mitochondrial fusion defect typical of dnm1 cells. Scale bar: 5 µm.