Fig. 6. (A-C) Endosomal STxB accumulation in Vps26 siRNA-treated cells. Cy3-STxB (red) was incubated with Vps26-depleted cells for 45 minutes at (A,B) 37°C or (C) 19.5°C. After fixation, cells were labeled for Vps26 (not shown) and TfR or EEA1 (green), as indicated. (A'-C') Magnified views of boxed areas of A-C. Additional magnification views are shown as insets in A',B',C'. (A"-C") The orientation of the shifts between STxB and TfR at 37°C (A"), STxB and EEA1 at 37°C (B"), and STxB and TfR at 19.5°C (C") are shown for the boxed areas in A-C, respectively. Centers of STxB-positive structures are marked `x' (red), centers of TfR or EEA1 positive structures are marked `+' (green). Colocalized structures are encircled, structures with shifts are marked by arrows. Dotted circles indicate ambiguous situations. Note that at 37°C, STxB-positive structures are neighboring to TfR- or EEA1-positive structures, whereas at 19.5°C, exact superposition is observed for STxB and TfR. Bars, 10 µm (A-C) and 5 µm (A'-C').