Genome-Wide Analysis Reveals the Vacuolar pH-Stat of Saccharomyces cerevisiae (original) (raw)
Figure 3
Lysosomal hyperacidification accompanies a cellular Niemann-Pick type C phenotype.
(a) Vacuoles in ergosterol accumulating ncr1Δ cells are hyperacidic, whereas erg mutants lacking ergosterol have abnormally alkaline vacuoles. (b) Intracellular sterol accumulates in ncr1Δ yeast. Yeast cells were stained with filipin to detect sterol in the presence or absence of NCR1. Bar, 2 µm. (c) Fibroblasts harboring pathogenic alleles of NPC1 (P237S/I1061T) have hyperacidified lysosomes. Wild type cells from a control subject (wt) or mutant cells from a patient with Niemann-Pick type C disease (NPC1−/−) were stained with acridine orange in the absence or presence of 10 nM concanamycin A1 (concan A), an inhibitor of the V-ATPase. Bar, 10 µm. Cellular acridine orange fluorescence was quantified relative to untreated wild type cells; bars represent standard deviations (n = 100 cells). (d) Nigericin prevents aberrant accumulation of cholesterol in lysosomes of NPC1−/− mutant cells. Cells were stained with filipin to detect cholesterol in the presence or absence of 10 nM nigericin, a K+/H+ ionophore.