Cells lacking Vps1 are defective in vacuolar and endosomal morphology and trafficking. (A) WT (W303A) and Δvps1 cells expressing GFP-FYVE were stained with FM 4–64 and were visualized by confocal microscopy. (B) WT and Δvps4 cells expressing Vps1-EGFP were stained with FM 4–64. (C) Visualization of WT cells expressing Vps1-EGFP and mCherry-FYVE. Vps1 puncta partially colocalized with FYVE puncta (67.8 ± 4.9%). (D) CPY maturation in Δvps1 cells. mCPY is the mature form, and P1 and P2 are intermediates. PGK1 is the loading control. The ratio of mature to total CPY was determined for each sample (n = 3). The means of the ratios of mature to total CPY were significantly heterogeneous (one-way ANOVA, F_4,10 = 10.1; P = 0.002). A Tukey-Kramer post hoc test was used to assess the significance of differences between means: those not significantly different from one another are indicated below the graph (P > 0.05), whereas selected pairs of means that are significantly different are indicated above the graph: *, P < 0.05; **, P < 0.01. Molecular masses are given in kilodaltons. (E) Visualization of cells expressing the indicated Vps1 mutant. Bars, 5 µm.