Figure 2.

RAB7 is essential for MIM to promote CXCR4 sorting into late endosomes. A–D, HeLa cells expressing GFP (A and B) or MIM-GFP (C and D) were plated in 6-well plates, treated with Ct-siRNA (A and C) or siRAB7 (B and D) for 48 h, and stimulated with 500 ng/ml SDF-1 for 30 min. The treated cells were costained with monoclonal CXCR4 antibody (green) and polyclonal CD63 antibody (red) and inspected by confocal microscopy. The boxed areas of images were amplified and are presented below. E, co-localization of CXCR4 and CD63 was quantitively analyzed based on Manders' coefficient, which represents the proportion of CD63 colocalized with CXCR4. F, the amount of CD63 puncta of the acquired images was also quantified. Scale bars = 10 μm. ***, p < 0.001 (n = 10).