Title: Different effects of the Ca(2+)-binding protein, KChIP1, on two Kv4 subfamily members, Kv4.1 and Kv4.2.

Authors: T Y Nakamura, S Nandi, D J Pountney, M Artman, B Rudy, W A Coetzee

Journal, date & volume: FEBS Lett., 2001 Jun 22 , 499, 205-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11423117

Abstract
The Ca(2+)-binding protein, K(+) channel-interacting protein 1 (KChIP1), modulates Kv4 channels. We show here that KChIP1 affects Kv4.1 and Kv4.2 currents differently. KChIP1 slows Kv4.2 inactivation but accelerates the Kv4.1 inactivation time course. Kv4.2 activation is shifted in a hyperpolarizing direction, whereas a depolarizing shift occurs for Kv4.1. On the other hand, KChIP1 increases the current amplitudes and accelerates recovery from inactivation of both currents. An involvement of the Kv4 N-terminus in these differential effects is demonstrated using chimeras of Kv4.2 and Kv4.1. These results reveal a novel interaction of KChIP1 with these two Kv4 members. This represents a mechanism to further increase the functional diversity of K(+) channels.