Fig. 9. Vps20p and Vta1p are required for MVB lipid sorting. Sorting of the lipid dye NBD-PC was followed in wild-type (SF838-9D), vps20 (SF838-9Dvpl10) and vta1 (PLY3046) cells. Cells labelled at 30°C with FM4-64 (2 µM) in potassium phosphate-buffered YPUAD (pH 7.0) for 20 minutes followed by incubation with NBD-PC (100 µM) for an additional 20 minutes. Cells were washed and resuspended in SD media and incubated for an additional 30 minutes at 30°C prior to fluorescence microscopy. Cells were resuspended in 1% sodium azide, 1% sodium fluoride, 100 mM Tris pH 8.0 prior to fluorescence and DIC microscopy. Bar, 5 µm.