Mechanism of "NBD engine" in an ABC transporter, CFTR channel

The cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) transporter superfamily, is an anion channel which plays an important fundamental role in fluid and electrolyte transport across epithelial tissues. In the most of ABC transporters, two highly-conserved nucleotide-binding domains (NBDs) form a common engine that utilizes the energy of ATP hydrolysis to active-transport a wide spectrum of substrates. In CFTR, the ATP-dependent “NBD engine” drives the gate of the ion conducting pore by cycles of ATP binding and hydrolysis. In this review, we introduce the recent advances in the studies for the molecular mechanism of ATP-dependent NBD engine in CFTR channels.