L79-Rab5, but not N34-Rab5, induces the formation of large endosomes and lamellipodia. Shown is immunofluorescence microscopy of A14 fibroblasts grown on coverslips and expressing either L79-Rab5 or N34-Rab5 as indicated. Rab5 expression and localization were visualized by anti-HA × GαM-Cy3 staining, the actin cytoskeleton was visualized by phalloidin-FITC, and microtubules were visualized by anti-tubulin × GαM-Cy3 (as indicated). The same cells are shown in the left and right panels. Bar, 30 μm.