Localization of full-length WT and ΔF508 CFTR (rows A and B, respectively), and amino- and carboxy-terminal fragments in cells expressing SplitΔRpIND or SplitΔRpIND+RDpNUT (rows C and D). Cells were fixed using paraformaldehyde and permeabilized with 0.1% Triton X-100 and then incubated with anti-CFTR antibodies L12B4, M3A7, or 450 (1:1000). Signals were detected using a secondary Cy3-conjugated goat anti-mouse antibody (1:100, in red, column i) or Cy5-conjugated goat anti-mouse antibody (1:200, in green for M3A7 (ii) or in light blue for 450 (iii)). Colocalization is shown for front half and back half (column iv) and for the front half and R domain (column v).