Regulation of CFTR channel gating

The debilitating symptoms of cystic fibrosis stem from the reduced Cl- permeability of epithelial cells owing to mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel. In cells with normal CFTR channels, receptor-mediated activation of cyclic-AMP-dependent protein kinase causes phosphorylation of several serines in the regulatory domain of CFTR, permitting channel opening and closing via cycles involving ATP hydrolysis. Cellular phosphatases rapidly dephosphorylate the channels, inactivating them. Here we discuss recent advances in our understanding of this complex mechanism for regulating channel gating.