Fig. 4. The large ring-shaped vesicles observed in the GFP-Rab11Q70L-transfected cells are labeled with Bodipy-ceramide. Stably transfected cells overexpressing the mutant GFP-Rab11Q70L were labeled with Lysotracker (Lys) or monodansylcadaverine (MDC) as described in the Materials and Methods. Late endosomes were labeled using an antibody against the mannose-6-phosphate receptor (M6PR) and a Texas-Red-conjugated goat-anti rabbit secondary antibody. Labeling with Bodipy-TR ceramide (B-Cer) was performed as described in the Materials and Methods. Cells were mounted on coverslips and analyzed by fluorescence microscopy. Images were obtained as described in Fig. 3.