Specification of subunit assembly by the hydrophilic amino-terminal domain of the Shaker potassium channel.
The functional heterogeneity of potassium channels in eukaryotic cells arises not only from the multiple potassium channel genes and splice variants but also from the combinatorial mixing of different potassium channel polypeptides to form heteromultimeric channels with distinct properties. One structural element that determines the compatibility of different potassium channel polypeptides in subunit assembly has now been localized to the hydrophilic amino-terminal domain. A Drosophila Shaker B (ShB) potassium channel truncated polypeptide that contains only the hydrophilic amino-terminal domain can form a homomultimer; the minimal requirement for the homophilic interaction has been localized to a fragment of 114 amino acids. Substitution of the amino-terminal domain of a distantly related mammalian potassium channel polypeptide (DRK1) with that of ShB permits the chimeric DRK1 polypeptide to coassemble with ShB.
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Howard Hughes Medical Institute, University of California, San Francisco 94143-0724.
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D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D016367:Baculoviridae; D001692:Biological Transport / Q000187:drug effects; D004330:Drosophila; D004591:Electrophoresis, Polyacrylamide Gel; D005796:Genes / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics* / Q000502:physiology; D016133:Polymerase Chain Reaction; D011188:Potassium / Q000493:pharmacokinetics; D015221:Potassium Channels / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology; D011993:Recombinant Fusion Proteins; D012689:Sequence Homology, Nucleic Acid; D051637:Shaker Superfamily of Potassium Channels
D010455:Peptides; D015221:Potassium Channels; D011993:Recombinant Fusion Proteins; C076413:Shaker B potassium channel polypeptide; D051637:Shaker Superfamily of Potassium Channels; D011188:Potassium