ABSTRACT
Large conductance Ca2+-activated K+ (BK) channels are activated by membrane depolarization and intracellular Ca2+. BK channels regulate membrane potential, intracellular Ca2+ concentration and ion transportation across the cell membrane. BK channels are composed of four Slo1 subunits that may associate with β and γ regulatory subunits. The Slo1 subunit contains a transmembrane voltage-sensor domain and a pore-gate domain as well as a cytosolic domain that serves as the Ca2+ sensor. BK channels exhibit an intrinsic opening in the absence of stimulation. Voltage and Ca2+ activate BK channels with allosteric mechanisms such that the activation of each voltage or Ca2+ sensor enhances pore opening. Peptide toxins, fatty acids and small molecule compounds are found to interact with the channel protein to inhibit or enhance BK channel function.
