Expression of the 551Δ3 dyn2 mutant does not inhibit transferrin endocytosis. COS-7 cells were transfected with the indicated constructs and incubated with Alexa Fluor 488–transferrin for 30 min. (A) Schematic representation of dyn2 indicating functional domains and mutation sites used in this experiment. GED, GTPase effector domain. (B) The expression levels of exogenous proteins were confirmed by immunoblotting using anti-V5. (C) Confocal micrographs showing the subcellular distribution of internalized transferrin (Tfn; green) in transfected cells (red). (D) Quantification of the effect of the indicated constructs on transferrin internalization. The number of cells containing Alexa Fluor 488–transferrin is expressed relative to the total number of transfected cells. (E) Effect of the 551Δ3 dyn2 mutant on the perinuclear localization of internalized transferrin. The number of cells with perinuclear transferrin is expressed relative to the total number of transfected cells. Error bars indicate SD from two independent experiments; *, P < 0.005. WT, wild type. Bar, 20 µm.