Figure 3.

Altered Rab7-positive late endosomal compartments in lrrk loss-of-function mutants. (A–J) Examination of a battery of endolysosomal markers in wild-type (A, C, E, G, I) and lrrk null mutant (B, D, F, H, J) follicle cells reveals no distinguishable difference between the early endosomal markers Rab5 (A versus B) or Hrs (C versus D), or the lysosomal markers Lysotracker (G versus H) or Lamp1:GFP (I versus J). A small portion of lrrk mutant follicle cells, however, did display dramatically expanded Rab7-positive late endosomes (marked with arrowheads in F) that were never observed in stage-matched wild-type follicle cells (E). (K and L) After a 30 min chase, fluorescently labeled dextran was taken up into wild-type follicle cells and trafficked predominantly to Rab7-positive late endosomes (K). In lrrk mutant follicle cells (L), some enlarged Rab7-positive structures accumulated massive amounts of dextran, while others were devoid of the tracer. Follicle cell nuclei are outlined with dashed gray lines in (A–J). Scale bars represent 5 μm.