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PMID: 17673911 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Identification of the PIP2-binding site on Kir6.2 by molecular modelling and functional analysis.

The EMBO journal ·Vol. 26 ·No. 16 ·2007-08-22 ·Pages 3749-59

Haider S, Tarasov AI, Craig TJ, Sansom MS, Ashcroft FM

Abstract

ATP-sensitive potassium (K(ATP)) channels couple cell metabolism to electrical activity by regulating K(+) fluxes across the plasma membrane. Channel closure is facilitated by ATP, which binds to the pore-forming subunit (Kir6.2). Conversely, channel opening is potentiated by phosphoinositol bisphosphate (PIP(2)), which binds to Kir6.2 and reduces channel inhibition by ATP. Here, we use homology modelling and ligand docking to identify the PIP(2)-binding site on Kir6.2. The model is consistent with a large amount of functional data and was further tested by mutagenesis. The fatty acyl tails of PIP(2) lie within the membrane and the head group extends downwards to interact with residues in the N terminus (K39, N41, R54), transmembrane domains (K67) and C terminus (R176, R177, E179, R301) of Kir6.2. Our model suggests how PIP(2) increases channel opening and decreases ATP binding and channel inhibition. It is likely to be applicable to the PIP(2)-binding site of other Kir channels, as the residues identified are conserved and influence PIP(2) sensitivity in other Kir channel family members.

MeSH Terms
Adenosine Triphosphate/metabolism Animals Binding Sites Humans Mice Models, Molecular Molecular Sequence Data Patch-Clamp Techniques Phosphatidylinositol 4,5-Diphosphate/metabolism Potassium Channels, Inwardly Rectifying/chemistry,genetics,metabolism Protein Binding Protein Conformation Rats
Chemicals
Kir6.2 channel Phosphatidylinositol 4,5-Diphosphate Potassium Channels, Inwardly Rectifying Adenosine Triphosphate
Authors & Affiliations
5 authors, click to expand affiliations / ORCID
Haider Shozeb
Department of Biochemistry, University of Oxford, Oxford, UK.
Tarasov Andrei I
Craig Tim J
Sansom Mark S P
Ashcroft Frances M
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Article Info
Journal
The EMBO journal
Abbr.
EMBO J
ISSN
0261-4189
DOI
10.1038/sj.emboj.7601809
Published
2007-08-22
Epub
2007-00-02
Pages
3749-59
Language
English
Region
England
NLM ID
8208664
PMCID
PMC1952224
Subset
IM
Grants
Wellcome Trust · United Kingdom
External Links
PubMed source DOI: 10.1038/sj.emboj.7601809 PMC Full Text View journal details
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