Fig. 5.

cAMP-activated Cl^- channel activity of L441P mutant CFTR. HEK 293 cells were transfected with plasmids for wild type CFTR or CFTR carrying the L441P mutation and the cAMP-activated Cl^- channel activity was measured in the whole cell configuration. (A) Cells were stimulated with forskolin (5 µM) and the currents were measured at a -30 mV holding potential. Mean currents were normalized as current densities (pA/pF, n=6 for wild type CFTR and n=10 for L441P mutant CFTR). (B) The I-V relationships were obtained with a step pulse from -120 mV to +120 mV applied at peak current.