Multifunctional Potassium Channels: Electrical Switches and Redox Enzymes, All in One

Abstract

Kv1-type K + channels are protein complexes containing both voltage-sensing, pore-forming α subunits and modulatory Kvβ subunits. Although some Kvβ subunits include an amino-terminal region that allows them to transform noninactivating Kv1 channels into rapidly inactivating channels, the function of Kvβ subunits that do not possess these inactivating amino-terminal regions has been less clear. Recent research demonstrates that Kvβ2 acts as an NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate)–dependent redox enzyme and that its catalytic activity can regulate the speed with which the Kv1.4-Kvβ2 complex undergoes inactivation, suggesting that Kvβ2 may link cellular metabolic activity and redox state with electrical signaling.