(c, d) MDA-MB-231 cells were transfected with EGFP-fused empty EV, VPS39, or VPS41. Cells were immunostained with RAB7 (c, red) or anti-MT1-MMP (d) antibodies. Merged images with DAPI (blue) are shown on the right. Enlarged endosomes in the boxed region are highly magnified in the insets. Diameters of RAB7 positive vesicles are also shown. n, number of cells scored for each cell population. Bars, 10 μm, (inset 5 μm). 