Abstract
Homomeric assembly of Kir5.1, an inward-rectifying K+ channel subunit, is believed to be nonfunctional, although the subunit exists abundantly in the brain. We show that HEK293T cells cotransfected with Kir5.1 and PSD-95 exhibit a Ba(2+)-sensitive inward-rectifying K+ current. Kir5.1 coexpressed with PSD-95 located on the plasma membrane in a clustered manner, while the Kir5.1 subunit expressed alone distributed mostly in cytoplasm, probably due to rapid internalization. The binding of Kir5.1 with PSD-95 was prevented by protein kinase A (PKA)-mediated phosphorylation of its carboxyl terminus. The currents flowing through Kir5.1/PSD-95 were suppressed promptly and reversibly by PKA activation. Because the Kir5.1/PSD-95 complex was detected in the brain, this functional brain K+ channel is potentially a novel physiological target of PKA-mediated signaling.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Barium / metabolism
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Brain / cytology
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Brain / metabolism*
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Cell Fractionation
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Cell Line
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Cells, Cultured
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Cyclic AMP-Dependent Protein Kinases / metabolism
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Disks Large Homolog 4 Protein
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Humans
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Intracellular Signaling Peptides and Proteins
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Membrane Proteins
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Neurons / metabolism*
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Neurons / ultrastructure
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Patch-Clamp Techniques
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Phosphorylation
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Potassium Channels, Inwardly Rectifying / genetics
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Potassium Channels, Inwardly Rectifying / metabolism*
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Protein Binding
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Protein Structure, Tertiary
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Protein Transport / physiology
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Rats
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Recombinant Fusion Proteins / metabolism
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Transfection
Substances
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Disks Large Homolog 4 Protein
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Dlg4 protein, rat
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Intracellular Signaling Peptides and Proteins
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Membrane Proteins
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Nerve Tissue Proteins
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Potassium Channels, Inwardly Rectifying
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Recombinant Fusion Proteins
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postsynaptic density proteins
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Barium
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Cyclic AMP-Dependent Protein Kinases