Two N-terminal domains of Kv4 K(+) channels regulate binding to and modulation by KChIP1.

The family of calcium binding proteins called KChIPs associates with Kv4 family K(+) channels and modulates their biophysical properties. Here, using mutagenesis and X-ray crystallography, we explore the interaction between Kv4 subunits and KChIP1. Two regions in the Kv4.2 N terminus, residues 7-11 and 71-90, are necessary for KChIP1 modulation ...
and interaction with Kv4.2. When inserted into the Kv1.2 N terminus, residues 71-90 of Kv4.2 are also sufficient to confer association with KChIP1. To provide a structural framework for these data, we solved the crystal structures of Kv4.3N and KChIP1 individually. Taken together with the mutagenesis data, the individual structures suggest that that the Kv4 N terminus is required for stable association with KChIP1, perhaps through a hydrophobic surface interaction, and that residues 71-90 in Kv4 subunits form a contact loop that mediates the specific association of KChIPs with Kv4 subunits.
Mesh Terms:
Amino Acid Sequence, Animals, Binding Sites, Calcium-Binding Proteins, Cell Line, Cell Membrane, Crystallography, X-Ray, Humans, Kv Channel-Interacting Proteins, Membrane Potentials, Models, Molecular, Mutagenesis, Site-Directed, Oocytes, Patch-Clamp Techniques, Potassium Channels, Potassium Channels, Voltage-Gated, Protein Binding, Protein Structure, Tertiary, Protein Subunits, Shal Potassium Channels
Neuron
Date: Feb. 19, 2004
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