(A) Vacuole morphology in Rab5 mutants. Cells with the indicated mutations were grown in the presence of 10 µM FM4-64 and analyzed by fluorescence microscopy. Size bar, 5 µm. (B) Quantification of vacuole morphology. Percentage of cells with less than four vacuoles is shown. Error bars represent standard deviation. (C) Model of cooperation of Rab5-GTP and PI-3-P for Mon1-Ccz1 recruitment to late endosomes. PI-3-P is indicated as red lipid. (D) Interaction of yeast Rab5-like proteins with Mon1-Ccz1. Purified GST-tagged Rab5 proteins (Vps21, Ypt10, Ypt52, and Ypt53) were loaded with GTP (T) or GDP (D) and incubated with purified Mon1-Ccz1 complex. Eluates were analyzed on SDS-PAGE by Western blotting with an antibody against the TAP-tag on Ccz1 (top) and Coomassie staining (bottom). For details see methods. (E) Localization of Ypt10 in yeast. Cells expressing endogenously GFP-tagged Ypt10 and mKate-tagged Ccz1 were analyzed by fluorescence microscopy. Size bar, 5 µm. (F) Analysis of Ypt7 localization and vacuole morphology in Rab5 deletion strains. mNeon-tagged Ypt7 was expressed under the control of the Ypt7 promoter in cells the indicated Rab5 proteins. Cells were stained with FM4-64, and analyzed by fluorescence microscopy. Size bar, 5 µm.
Figure 1—source data 1. Quantification of vacuole number in FM4-64 stained wild-type and mutant strains in Figure 1A.