Fig. 6. The WLM motif is necessary for endosome-to-TGN retrieval. (A) Cells expressing the alanine scanning mutants (see Fig. 5) were incubated with anti-CD8 continuously for three hours prior to fixation and labelling with anti-TGN46 and appropriate secondary antibodies. Mutant 7 fails to retrieve to the TGN. Bar, 20 µm. (B) The mutant 7-expressing cells were treated as above but labelled with anti-VPS26 instead of anti-TGN46 followed by appropriate secondary antibodies. There is significant colocalisation between endocytosed anti-CD8 and VPS26 (shown enlarged in the inset boxes and highlighted by arrows). Bar, 20 µm.