MaxiK channels: Molecular structure, function, and tissue distribution

Potassium channels are proteins in cell plasma membranes that allow the flux of potassium ions in and out of cells. They control a variety of different cell functions. Through openings these ion channels stabilize the resting membrane potential and in excitable cells that will lead to the resting membrane potential, repolarizes action potentials and will end series of action potential firing. In non-excitable cells potassium channels play a role in transport mechanisms, volume regulation, and signal transduction. Through a combination of electrophysiological and molecular biological techniques a variety of different potassium channel types have been identified compared to other ion channel families, like the voltage-gated sodium and calcium channels. In the following we will concentrate on one family of those potassium channels with 1pore and 6transmembrane regions, the voltage- and calcium-activated potassium channels with large conductance, the MaxiK or BK channels.