The coexpression of the rat Kvβ1 subunit with the mouse Kv1.1 (mKv1.1) K+ channel in Chinese hamster ovary cells caused an increase in the rate of inactivation of whole-cell current. Current decayed in a bi-exponential fashion with a fast voltage-dependent and a slower voltage-independent component. The inactivating current component accounted for around 40% of the total outward current. In contrast to previous studies using K+ channel α subunits, peptides based on the N-terminal of the Kvβ1 subunit were unable to mimic the action of the entire subunit. The findings indicate differences between the inactivation induced by the Kvβ1 subunit and the N-type inactivation mechanism associated with certain rapidly-inactivating cloned K+ channel α subunits.
