Intracellular cysteines of the cystic fibrosis transmembrane conductance regulator (CFTR) modulate channel gating.

The cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette superfamily, is a cAMP-activated chloride channel. CFTR contains two transmembrane domains (TMDs), two nucleotide-binding domains (NBDs), and a regulatory (R) domain. We found that whole-cell CFTR-dependent Cl- currents in Xenopus laevis oocytes were sensitive to HgCl(2), suggesting that modification of endogenous cysteines alters channel activity.