Fig. 1. F508-del co-localizes with the ER marker KDEL. CFBE41o^- cells stably expressing F508-del- CFBE41o^- cells were transfected with KDEL-td-tomato plasmid (Red, ER) and plated on coverslips. After 48 h, the cells were fixed, permeabilized, and stained with DAPI (blue, nucleus) and antibodies against CFTR (green, CFTR 596). Representative extended-focus images are shown. The cell shown is one representative example of F508-del /KDEL colocalization (yellow) taken from three independent experiments. All cells that were successfully transfected with the KDEL-td-tomato plasmid displayed co-localization (yellow) between KDEL and F508-del. The location of the green dots over the nucleus in the middle panel occurred because the level of focus of this image includes the cytoplasm, which contains F508-del and the nuclear marker (DAPI). Note, however, that in the left panel that there is no co-localization between the nuclear marker DAPI and F508-del, indicating that F508-del is not located within the nucleus.