Fig. 6. Rab9 overexpression overcomes intracellular cholesterol accumulation. BHK-21 cells expressing CFTR or F508 CFTR were transfected with a plasmid encoding Rab9-EGFP (Choudhury et al., 2002). After 24 hours, the cells were shifted to 27°C and incubated for another 24 hours, before staining for intracellular cholesterol with filipin. Three representative panels of cells expressing wild-type or F508 CFTR are shown. Cells that overexpress Rab9-EGFP are indicated by an arrow in the filipin panel. The punctate filipin staining is cleared from cells expressing Rab9-EGFP and F508 CFTR, but remains unchanged in a perinuclear Golgi-like location in cells expressing Rab9-EGFP and CFTR. Approximately 90 cells of three different experiments were quantified and data are shown in a histogram.