Multifunctional potassium channels: electrical switches and redox enzymes, all in one.

Kv1-type K+ channels are protein complexes containing both voltage-sensing, pore-forming alpha subunits and modulatory Kvbeta subunits. Although some Kvbeta subunits include an amino-terminal region that allows them to transform noninactivating Kv1 channels into rapidly inactivating channels, the function of Kvbeta subunits that do not possess these inactivating amino-terminal regions has been less clear. Recent research demonstrates that Kvbeta2 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-Kvbeta2 complex undergoes inactivation, suggesting that Kvbeta2 may link cellular metabolic activity and redox state with electrical signaling.