FIGURE 4.
Maturation of ferret ΔF508-CFTR band B to band C is more efficient than the human ortholog in HT1080 cells. A, metabolic [35S]methionine pulse-chase experiments were performed on HT1080 cells transiently expressing HA-tagged ferret and human ΔF508-CFTR to evaluate the rate of band B disappearance and maturation efficiency of the proteins as done in Fig. 3. Top and bottom panels are representative autoradiographs for ferret and human ΔF508-CFTR, respectively. B, shown is quantification of the average intensity of band B at 0 h (Band B0) for ferret and human ΔF508-CFTR normalized to total protein. C, shown is quantification of the disappearance of band B over the course of the experiment relative to Band B0 (Band BT/Band B0). D, shown is quantification of the maturation efficiency as calculated by the percentage of band C4 h relative to band B0. Data in all graphs represent the mean ± S.E. with n = 4 for panel C and n = 9 for panels B and D derived from three independent experiments done in triplicate. Marked comparisons (*) demonstrate significant differences relative to ferret ΔF508-CFTR as determined by Student's t test (p < 0.0001).