Dataset Information

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

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 ?···? 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.

SUBMITTER: Gebhardt M

PROVIDER: S-EPMC3064186 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Gebhardt Manuela M Hoffgaard Franziska F Hamacher Kay K Kast Stefan M SM Moroni Anna A Thiel Gerhard G

The Journal of biological chemistry 20110210 13

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 b ...[more]

PMID: 21310959

Similar Datasets

Project description:CLC anion channels are homodimeric proteins. Each subunit is comprised of 18 α-helices designated "A-R" and an intracellular carboxy-terminus containing two cystathionine-β-synthase (CBS1 and CBS2) domains. Conformational coupling between membrane and intracellular domains via poorly understood mechanisms is required for CLC regulation. The activity of the C. elegans CLC channel CLH-3b is reduced by phosphorylation of a carboxy-terminus "activation domain," which disrupts its interaction with CBS domains. CBS2 interfaces with a short intracellular loop, the H-I loop, connecting membrane helices H and I. Alanine mutation of a conserved H-I loop tyrosine residue, Y232, prevents regulation demonstrating that the loop functions to couple phosphorylation-dependent CBS domain conformational changes to channel membrane domains. To gain further insight into the mechanisms of this coupling, we mutated conserved amino acid residues in membrane helices H and I. Only mutation of the H-helix valine residue V228 to leucine prevented phosphorylation-dependent channel regulation. Structural and functional studies of other CLC proteins suggest that V228 may interact with Y529, a conserved R-helix tyrosine residue that forms part of the CLC ion conduction pathway. Mutation of Y529 to alanine also prevented CLH-3b regulation. Intracellular application of the sulfhydryl reactive reagent MTSET using CLH-3b channels engineered with single-cysteine residues in CBS2 indicate that V228L, Y529A, and Y232A disrupt putative regulatory intracellular conformational changes. Extracellular Zn2+ inhibits CLH-3b and alters the effects of intracellular MTSET on channel activity. The effects of Zn2+ are disrupted by V228L, Y529A, and Y232A. Collectively, our findings indicate that there is conformational coupling between CBS domains and the H and R membrane helices mediated by the H-I loop. We propose a simple model by which conformational changes in H and R helices mediate CLH-3b regulation by activation domain phosphorylation.

Dataset Information

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

Publications

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets