Figure 1. Schematic representation of the CFTR traffic reporter construct.

(a) Topology of the CFTR molecule showing the two membrane-spanning domains (MSD), the two nucleotide binding domains (NBD) and the regulatory domain (R Domain). Phe508 locates in the first NBD domain. mCherry was fused to the N-terminus of CFTR via a short linker sequence. The Flag-tag was introduced in the fourth extracellular loop and becomes accessible to the extracellular space when the construct is inserted in the plasma membrane. Both wt and F508del variants were generated. (b) Amino acid sequence showing the linker (light gray shadow) connecting mCherry and CFTR (dark gray shadows). (c) CFTR amino acid sequences showing the insertion of the Flag octapeptide between Asn901 and Ser902.