Abstract
Proper ion channel function often requires specific combinations of pore-forming alpha and regulatory beta subunits, but little is known about the mechanisms that regulate the surface expression of different channel combinations. Our studies of ATP-sensitive K+ channel (K(ATP)) trafficking reveal an essential quality control function for a trafficking motif present in each of the alpha (Kir6.1/2) and beta (SUR1) subunits of the K(ATP) complex. We show that this novel motif for endoplasmic reticulum (ER) retention/retrieval is required at multiple stages of K(ATP) assembly to restrict surface expression to fully assembled and correctly regulated octameric channels. We conclude that exposure of a three amino acid motif (RKR) can explain how assembly of an ion channel complex is coupled to intracellular trafficking.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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ATP-Binding Cassette Transporters*
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Adenosine Triphosphate / physiology*
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Amino Acid Sequence
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Animals
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COS Cells
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Cell Membrane / metabolism
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Cell Membrane / physiology
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Electrophysiology
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Endoplasmic Reticulum / physiology*
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Flow Cytometry
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Fluorescent Antibody Technique, Direct
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Membrane Potentials
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Mice
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Molecular Sequence Data
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Oocytes
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Patch-Clamp Techniques
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Potassium Channels / biosynthesis
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Potassium Channels / metabolism*
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Potassium Channels, Inwardly Rectifying*
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Rats
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Receptors, Drug / biosynthesis
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Receptors, Drug / metabolism
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Signal Transduction / physiology*
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Sulfonylurea Receptors
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Xenopus
Substances
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ATP-Binding Cassette Transporters
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Abcc8 protein, mouse
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Abcc8 protein, rat
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Potassium Channels
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Potassium Channels, Inwardly Rectifying
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Receptors, Drug
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Sulfonylurea Receptors
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Adenosine Triphosphate