THE MODULATION OF THE RATE OF INACTIVATION OF THE MKV1.1 K-SUBUNIT, KV-BETA-1 AND LACK OF EFFECT OF A KV-BETA-1 N-TERMINAL PEPTIDE( CHANNELBY THE BETA)

The coexpression of the rat Kv beta 1 subunit with the mouse Kv1.1 (mK v1.1) K+ channel in Chinese hamster ovary cells caused an increase in the rate of inactivation of whole-cell current. Current decayed in a b i-exponential fashion with a fast voltage-dependent and a slower volta ge-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-termi nal of the Kv beta 1 subunit were unable to mimic the action of the en tire subunit. The findings indicate differences between the inactivati on induced by the Kv beta 1 subunit and the N-type inactivation mechan ism associated with certain rapidly-inactivating cloned K+ channel alp ha subunits.