, Volume 63, Issue 1, pp 12-24,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 28 Nov 2005

Diversity of Cl Channels


Cl channels are widely found anion pores that are regulated by a variety of signals and that play various roles. On the basis of molecular biologic findings, ligand-gated Cl channels in synapses, cystic fibrosis transmembrane conductors (CFTRs) and ClC channel types have been established, followed by bestrophin and possibly by tweety, which encode Ca2+-activated Cl channels. The ClC family has been shown to possess a variety of functions, including stabilization of membrane potential, excitation, cellvolume regulation, fluid transport, protein degradation in endosomal vesicles and possibly cell growth. The molecular structure of Cl channel types varies from 1 to 12 transmembrane segments. By means of computer-based prediction, functional Cl channels have been synthesized artificially, revealing that many possible ion pores are hidden in channel, transporter or unidentified hydrophobic membrane proteins. Thus, novel Cl-conducting pores may be occasionally discovered, and evidence from molecular biologic studies will clarify their physiologic and pathophysiologic roles.

Received 28 July 2005; received after revision 25 August 2005; accepted 21 September 2005