Expression of Ub-EEA1 blocks the recycling of the transferrin receptor. COS7 cells transfected with the Ub-EEA1-expressing plasmid were fixed and immunostained with an antibody against transferrin receptor (TfR) (A, red channel in C) and anti-EEA1 antibody (B, green channel in C). Cells were also stained with DAPI in blue. Arrow heads label two untransfected cells that contain many transferrin receptor molecules in recycling vesicles. By contrast, the circled Ub-EEA1-expressing cells contain few TfR positive recycling vesicles. The scale bars correspond to 20 μm.