Figure 2. DNM1 mutations inhibit transferrin uptake.

Inhibition of transferrin internalization in mammalian cell lines. COS-7 cells were transfected with green fluorescent protein (GFP)-tagged DNM1 constructs and then treated with fluorescently labeled transferrin. Scale bar, 20 μm. (A) Cells expressing wild type (WT) DNM1 exhibit transferrin uptake with a perinuclear accumulation. WT DNM1 forms round puncta that are evenly dispersed throughout the perimeter of the cell. (B) The A177P mutant inhibits transferrin uptake. DNM1 shows some diffuse GFP signal throughout the cytosol accompanied by puncta. (C) The K206N mutant also inhibits transferrin uptake and shows abnormal aggregation of DNM1. (D) The G359A mutant shows some transferrin uptake in certain cells. There is a distinct lack of puncta, and DNM1 shows a reticular GFP signal throughout the cytosol.