FIGURE 5.

A, total lysate (TL) level of ERAD proteins and CFTR in the ΔF508. HEK-293 cell lines stably expressing ΔF508 were treated with C18 and C4 for 16 h. Protein samples were used for immunoblotting and incubated with different primary antibodies as presented in B. The combination of C18 and C4 affects the binding of Hsp27 and -40 to ΔF508. HEK-293 cells were stably transfected with ΔF508 and treated with C18 + C4 (10 μm) for 16 h. CFTR was immunoprecipitated (IP) with M3A7 (anti-CFTR antibody) and incubated with A/G beads for 4 h at 4 °C. Immunoblotting was performed, and samples were incubated with different primary antibodies as shown in C and D. Quantification of data for Hsp27 and -40, respectively. Versus untreated: *, p < 0.05; **, p < 0.01 (n = 4). Please note that there is an ∼20% reduction on the pull-down of both chaperones after treatment. However, when the increase in CFTR is taken into account there is a large reduction in the binding of both chaperones to CFTR.