Fig. 1.

D110C/K892C-CFTR macroscopic currents were highly potentiated by DTT. Traces show change in whole cell conductance (G) over time during activation of CFTR by stimulation of coexpressed β₂-adrenergic receptor (β₂-AR) using isoproterenol and subsequent exposure to DTT in the continuing presence of isoproterenol. A–E: D110C/K892C-CFTR, WT-CFTR, K892C-CFTR, D110C-CFTR, and D110A-CFTR, all activated by 10 μM isoproterenol (ISO) and then exposed to 1 mM DTT for 5 min. F: fold increase of conductance [i.e., slope between membrane potential (V_m) = −40 and 0 mV] after 5 min of DTT application for all variants tested. Dashed line indicates level of no change (i.e., “fold change of 1”). *P < 0.05.