Figure 6.

Detection of cell-surface expression of TGN38 variants by indirect immunofluorescence. Cells expressing wild-type TGN38 (A and B), S331A (C and D), or S331D (E and F) were subjected to paraformaldehyde fixation followed by incubation in the absence (A, C, and E), or presence (B, D, and F) of 0.1% Triton X-100 to permeabilize the plasma membrane. TGN38 was detected with a monoclonal antibody to TGN38 (2F7.1) followed by FITC-conjugated anti-mouse Ig. Surface antigen on detergent-permeabilized cells is not visible in these images due to the comparatively bright epifluorescence contributed by staining of intracellular TGN38.