Figure 8. Loss of miniCORVET leads to fragmentation of endosomes, unlike HOPS defects.

Vps8¹ mutant (B) garland nephrocytes lack normal sized α-vacuoles and only small vesicles can be found, unlike in control (A,D) or rescued (C) cells. In contrast, nephrocytes lacking either the HOPS specific subunit Lt/Vps41 (E) or Vps11 (F) contain enlarged α-vacuoles, which often have multiple cores. The simultaneous loss of both miniCORVET and HOPS function in vps16A single (G) or lt and vps8 double mutant cells (H) also results in fragmented, small α-vacuoles similar to vps8 single mutants. Note that these nephrocytes also contain numerous small electron-dense organelles, which may represent a Golgi-derived pre-lysosomal compartment. N: nucleus, M: mitochondria, ER: endoplasmic reticulum. (I) Quantification of data from panels (A–G). The size of each endosome is represented as a single punctum on the dot plots. Red lines and numbers show the mean endosome area in µm². Bars: 1 µm. Please see Figure 8—figure supplement 1. for additional data.

DOI: http://dx.doi.org/10.7554/eLife.14226.017

Figure 8—figure supplement 1. Additional miniCORVET and HOPS mutant nephrocyte data.

Low magnification ultrastructural images of garland nephrocytes. Large α-vacuoles containing a single dense core that are clearly visible in control cells (A) are absent from cells lacking miniCORVET (B–F). In cells that retain miniCORVET function but lack HOPS, α-vacuoles are greatly enlarged, and aberrant α-vacuoles with darker lumen accumulate in the perinuclear region (G–I). The simultaneous lack of both miniCORVET and HOPS function (C–F) leads to the appearance of numerous small electron-dense primary lysosome-like granules. Bars: 5 µm.

DOI: http://dx.doi.org/10.7554/eLife.14226.018