The modulation of the rate of inactivation of the mKv1.1 K+ channel by the beta subunit, Kv beta 1 and lack of effect of a Kv beta 1 N-terminal peptide.

The coexpression of the rat Kv beta 1 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 alpha subunits, peptides based on the N-terminal of the Kv beta 1 subunit were unable to mimic the action of the entire subunit. The findings indicate differences between the inactivation induced by the Kv beta 1 subunit and the N-type inactivation mechanism associated with certain rapidly-inactivating cloned K+ channel alpha subunits.