Referenced in: none

Automatically associated channels: KChIP1 , Kv1.4 , Kv3.1 , Kv4.1 , Kv4.2 , Kv4.3

Title: Structural insights into the functional interaction of KChIP1 with Shal-type K(+) channels.

Authors: Wei Zhou, Yan Qian, Kumud Kunjilwar, Paul J Pfaffinger, Senyon Choe

Journal, date & volume: Neuron, 2004 Feb 19 , 41, 573-86

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/14980206

Abstract
Four Kv channel-interacting proteins (KChIP1 through KChIP4) interact directly with the N-terminal domain of three Shal-type voltage-gated potassium channels (Kv4.1, Kv4.2, and Kv4.3) to modulate cell surface expression and function of Kv4 channels. Here we report a 2.0 Angstrom crystal structure of the core domain of KChIP1 (KChIP1*) in complex with the N-terminal fragment of Kv4.2 (Kv4.2N30). The complex reveals a clam-shaped dimeric assembly. Four EF-hands from each KChIP1 form each shell of the clam. The N-terminal end of Kv4.2 forming an alpha helix (alpha1) and the C-terminal alpha helix (H10) of KChIP1 are enclosed nearly coaxially by these shells. As a result, the H10 of KChIP1 and alpha1 of Kv4.2 mediate interactions between these two molecules, structurally reminiscent of the interactions between calmodulin and its target peptides. Site-specific mutagenesis combined with functional characterization shows that those interactions mediated by alpha1 and H10 are essential to the modulation of Kv4.2 by KChIPs.