Kv4.2: Proteins and Enzymes

Kv4.2, a voltage-gated K+ (Kv) channel subunit, has been suggested to be the key component of the subthreshold A-type K+ currents (I(SA)s) recorded from the specific subcellular compartments of certain CNS neurons (1). A-type channels, encoded by the pore-forming alpha-subunits of the Kv4.x family, are particularly important in regulating membrane excitability in the CNS and the heart. Kv4.2 is a Shal-type potassium channel that passes an A-type current and is localized to dendrites and cell bodies in the hippocampus (2). Deletion of the Kv4.2 gene and a loss of Kv4.2 protein resulted in a specific and near-complete elimination of A-type K+ currents from the apical dendrites of CA1 pyramidal neurons. The absence of dendritic Kv4.2-encoded A-type K+ currents led to an increase of bAP amplitude and an increase of concurrent Ca2+ influx (3).