title: Multiple PIP2 binding sites in Kir2.1 inwardly rectifying potassium channels.
abstract: Inwardly rectifying potassium channels require binding of phosphatidylinositol-4,5-bisphosphate (PIP2) for channel activity. Three independent sites (aa 175-206, aa 207-246, aa 324-365) were located in the C-terminal domain of Kir2.1 channels by assaying the binding of overlapping fragments to PIP2 containing liposomes. Mutations in the first site, which abolished channel activity, reduced PIP2 binding of this fragment but not of the complete C-terminus. Point mutations in the third site also reduced both, channel activity and PIP2 binding of this segment. The relevance of the third PIP2 binding site provides a basis for the understanding of constitutively active Kir2 channels.
authors.affiliation: Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Soom
authors.forename: R
authors.initials: R
authors.lastname: Schönherr
authors.forename: Y
authors.initials: Y
authors.lastname: Kubo
authors.forename: C
authors.initials: C
authors.lastname: Kirsch
authors.forename: R
authors.initials: R
authors.lastname: Klinger
authors.forename: S H
authors.initials: SH
authors.lastname: Heinemann
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D017354:Point Mutation; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D005656:Fungal Proteins; D008081:Liposomes; C100530:PIP2 protein, S cerevisiae; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase