Loss of v100 causes endosomal and autophagic accumulations. (A) Schematic of heterogeneous intracellular accumulations in the v100 mutant. (B) Ratio of expression levels in mutant photoreceptor terminals compared with WT control (ctrl) in 50% mosaics. The red line represents unaltered levels. Note that numerous endosomal and lysosomal membrane markers are up-regulated. (C and D) Representative transmission electron micrographs reveal aberrant multivesicular structures and AVs (MVBs [arrowhead] and AVs [arrow]) in v100 mutant photoreceptor terminals. (E) Quantification of MVB-like (single membrane) and AV-like (double membrane) structures per photoreceptor terminals show a more than fivefold increase in the mutant (P < 0.01). (F and G) Coimmunolabeling of early endosomes using Syx7 and Rab5 reveals strong up-regulation in mutant cells. (H and I) Coimmunolabeling of Syx7 and Rab7. (J and K) Colabeling of autophagosomes using Atg8-GFP and anti-Syx7 labeling reveals both makers accumulating in mostly separate compartments. (L and M) Colabeling of early endosomes using 2xFYVE-GFP and lysosomes using anti-Sunglasses reveals that both markers accumulate in mutually exclusive compartments. EE, early endosome; MVB, multivesicular body/late endosome; Ly, Lysosome; SV, synaptic vesicle; RE, recycling endosome; RV, recycling vesicle. Error bars indicate SEM. Bars: (C) 5 µm; (G) 1 µm.