Figure 4

Estimation of vesicle size and example trajectories of vesicles containing BChol. After cells were labeled and chased with BChol, as described in the legend to Figure 3, vesicles were found throughout the cytoplasm with the majority of vesicles in the perinuclear region (A). The average vesicle size was determined by fitting a 2D Gaussian function to images of the vesicles. Panel B shows a vesicle from the ROI in panel A (image size 2.4 x 2.4 μm) while panel C shows a fit of the 2D Gaussian to the vesicle. The vesicle sizes had a distribution with diameters ranging from 0.2 – 0.7 μm with an average size of 0.45 ± 0.1 μm (panel D). To monitor their mobility, vesicles were tracked and their trajectories analyzed. Panel E shows examples of vesicle trajectories. Bar, 5 μm.