FIGURE 7.

L803-mts restores lysosomal acidification in PS1/2-deficient cells. A, levels of glycosylated (120 kDa) and nonglycosylated (100 kDa) v-ATPase V0a1, CatD (∼48–50 kDa), and mCatD (∼32 kDa) were determined in MEF and MEF-PS1/2^−/− cells by immunoblot analysis. B, MEF and MEF-PS1/2^−/− cells were stained with LysoTracker Red and imaged by confocal microscopy (top panels). MEF-PS1/2^−/− cells were treated with L803-mts (40 μm), SB-216763 (5 μm), and LiCl (20 mm) for 4 h. The cells were stained with LysoTracker Red and imaged by confocal microscopy (bottom panels). The scale bars represent 10 μm. C, MEF-PS1/2^−/− cells were treated with L803-mts (40 μm), SB-216763 (5 μm), and LiCl (20 mm). The lysosomes were partially purified as described under “Experimental Procedures.” Lysosome precipitates were immunoblotted for Lamp1, v-ATPase V0a1, CatD, and mCatD. The faint band corresponding to the 14-kDa mCatD is shown.