Stoichiometry of Kir channels with phosphatidylinositol bisphosphate
| Autor: | Avia Rosenhouse-Dantsker, Jin Liang Sui, Lily Yeh Jan, Kim W. Chan, Taihao Jin, Diomedes E. Logothetis |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
musculoskeletal diseases
Time Factors Xenopus Phosphatidylinositol Phosphates Biophysics Gating Biochemistry Models Biological Cell membrane Bursting medicine Animals Humans Enzyme Inhibitors Potassium Channels Inwardly Rectifying Ion channel biology Chemistry Cell Membrane biology.organism_classification Affinities Kinetics Membrane medicine.anatomical_structure Models Chemical Mutation lipids (amino acids peptides and proteins) Female Dimerization Ion Channel Gating |
| Zdroj: | Channels (Austin, Tex.). 2(1) |
| ISSN: | 1933-6969 |
| Popis: | Phosphatidylinositol bisphosphate (PIP(2)) is the most abundant phosphoinositide in the plasma membrane of cells and its interaction with many ion channel proteins has proven to be a critical factor enabling ion channel gating. All members of the inwardly rectifying potassium (Kir) channel family depend on PIP(2) for their activity, displaying distinct affinities and stereospecificities of interaction with the phosphoinositide. Here, we explored the stoichiometry of Kir channels with PIP(2). We first showed that PIP(2) regulated the activity of Kir3.4 channels mainly by altering their bursting behavior. Detailed burst analysis indicates that the channels assumed up to four open states and a connectivity of four between open and closed states depending on the available PIP(2) levels. Moreover, by controlling the number of PIP(2)-sensitive subunits in the stoichiometry of a tetrameric Kir2.1 channel, we showed that characteristic channel activity was obtained when at least two wild-type subunits were present. Our studies support a kinetic model for gating of Kir channels by PIP(2), where each of the four open states corresponds to the channel activated by one to four PIP(2) molecules. |
| Databáze: | OpenAIRE |
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