Referenced in: none

Automatically associated channels: Kir2.2

Title: Membrane anchoring and interaction between transmembrane domains are crucial for K+ channel function.

Authors: Manuela Gebhardt, Franziska Hoffgaard, Kay Hamacher, Stefan M Kast, Anna Moroni, Gerhard Thiel

Journal, date & volume: J. Biol. Chem., 2011 Apr 1 , 286, 11299-306

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21310959

Abstract
The small viral channel Kcv is a Kir-like K(+) channel of only 94 amino acids. With this simple structure, the tetramer of Kcv represents the pore module of all complex K(+) channels. To examine the structural contribution of the transmembrane domains (TMDs) to channel function, we performed Ala scanning mutagenesis of the two domains and tested the functionality of the mutants in a yeast complementation assay. The data reveal, in combination with computational models, that the upper halves of both TMDs, which face toward the external medium, are rather rigid, whereas the inner parts are more flexible. The rigidity of the outer TMD is conferred by a number of essential aromatic amino acids that face the membrane and probably anchor this domain in the bilayer. The inner TMD is intimately connected with the rigid part of the outer TMD via π···π interactions between a pair of aromatic amino acids. This structural principle is conserved within the viral K(+) channels and also present in Kir2.2, implying a general importance of this architecture for K(+) channel function.