Fig. (6).

CFTR inhibition by PPQ / BPO compounds. A. Single-channel patch-clamp recordings in the cell-attached configuration in CFTR-expressing FRT cells. CFTR was activated by 10 μM forskolin and 100 μM IBMX (holding voltage +80 mV). B. Dose-response for inhibition of CFTR Cl⁻ current in which CFTR was activated by 100 μM CPT-cAMP. C. CFTR inhibition by enantiopure (R)-BPO-27 shown by short-circuit current. Adapted from refs. 45 and 46. D. (left) Low resolution structure of CFTR. (right) (R)-BPO-27 docked into the ATP-binding site of a high-resolution crystal structure of the head-to-tail NBD1-NBD1 homodimer (pdb = 2PZE).