Abstract
S-SCAM has a similar molecular organization to PSD-95. Both of them interact with a cell adhesion molecule, neuroligin. We previously reported that beta-catenin binds S-SCAM and recruits it to synapses. We have here examined using rat primary cultured neurons whether neuroligin recruits S-SCAM to synapses or S-SCAM determines the localization of neuroligin. Overexpressed neuroligin formed larger clusters under co-expression of S-SCAM but not of PSD-95. Overexpressed neuroligin blocked synaptic accumulation of PSD-95 but not of S-SCAM. S-SCAM mutant containing the neuroligin-binding region interfered with synaptic accumulation of neuroligin and PSD-95, whereas the similar mutant of PSD-95 had no effect. Biochemical studies revealed that neuroligin forms a ternary complex with S-SCAM and PSD-95 through manifold interactions. These findings imply that S-SCAM is tethered by beta-catenin to synapses and induces synaptic accumulation of neuroligin, which subsequently recruits PSD-95 to synapses.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Animals
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COS Cells
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Adhesion / genetics
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Cell Adhesion Molecules, Neuronal
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Cell Differentiation / genetics
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Cells, Cultured
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Cytoskeletal Proteins / metabolism
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Dendrites / metabolism
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Dendrites / ultrastructure
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Disks Large Homolog 4 Protein
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Guanylate Kinases
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Hippocampus / cytology
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Hippocampus / embryology*
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Hippocampus / metabolism*
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Intracellular Signaling Peptides and Proteins
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Macromolecular Substances
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Membrane Proteins / metabolism*
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Mutation / genetics
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Protein Binding / genetics
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Protein Structure, Tertiary / genetics
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Rats
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Synapses / metabolism*
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Synapses / ultrastructure
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Synaptic Membranes / metabolism
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Trans-Activators / metabolism
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beta Catenin
Substances
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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Cell Adhesion Molecules, Neuronal
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Ctnnb1 protein, rat
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Cytoskeletal Proteins
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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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Macromolecular Substances
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Magi2 protein, rat
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Membrane Proteins
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Nerve Tissue Proteins
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Trans-Activators
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beta Catenin
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neuroligin 1
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postsynaptic density proteins
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Guanylate Kinases