Alternative splicing of the human Shaker K+ channel β1 gene and functional expression of the β2 gene product

Mammalian voltage-activated Shaker K+ channels associate with at least three cytoplasmic proteins: Kvβ1, Kvβ2 and Kvβ3. These β subnunits contain variable N-termini, which can modulate the inactivation of Shaker α subunits, but are homologous throughout an aldo-keto reductase core. Human and ferret β3 proteins are identical with rat β1 throughout the core while β2 proteins are not; β2 also contains a shorter N-terminus and has no reported physiological role. We report that human β1 and β3 are derived from the same gene and that β2 modulates the inactivation properties of Kv1.4 α subunits.