Figure 1.

Wild type (WT)–cystic fibrosis transmembrane conductance regulator (CFTR) is translated at the ribosome on the endoplasmic reticulum (ER), and the membrane spanning domain (MSD) penetrates the ER membrane. Upon translation, each domain of the CFTR is folded with the assistance of chaperone–cochaperone complexes on the cytoplasmic side and inside of the ER to form a metastable structure (Co-translational folding). After the translation is completed, the domains interact by the action of the chaperones to form a native structure (Post-translational folding). Found in the nucleotide binding domain 1 (NBD1) of WT–CFTR, the ER export motif is exposed and CFTR is transported from the ER to the Golgi apparatus by coat protein complex II (COP II) vesicles.