Abstract
Acetylcholine receptors (AChRs) and other postsynaptic molecules cluster spontaneously on cultured C2 myotubes. The frequency of clustering is enhanced by neural agrin, neuraminidase, or calcium through a signaling pathway which includes tyrosine phosphorylation of a muscle-specific kinase (MuSK) and the AChR beta-subunit. Vicia villosa agglutinin (VVA) lectin, previously shown to potentiate agrin-induced clustering on C2 myotubes, is shown here to also potentiate neuraminidase- and calcium-induced clustering of AChRs, while having no effect on the level of tyrosine phosphorylation of MuSK or the AChR beta-subunit. We propose that VVA lectin increases the frequency of AChR clustering through a mechanism that is distinct from agrin signaling, and that may involve alpha-dystroglycan.
Copyright 2000 S. Karger AG, Basel
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Agrin / physiology*
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Animals
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Calcium / metabolism
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Calcium / pharmacology
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Cells, Cultured
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Cytoskeletal Proteins / metabolism
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Dystroglycans
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Laminin / metabolism
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Lectins / metabolism
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Lectins / pharmacology
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Membrane Glycoproteins / metabolism
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Mice
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Muscle Fibers, Skeletal / chemistry
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Muscle Fibers, Skeletal / cytology
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Muscle Fibers, Skeletal / enzymology
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N-Acetylneuraminic Acid / metabolism
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Neuraminidase / pharmacology
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Neuromuscular Junction / chemistry*
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Neuromuscular Junction / cytology
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Neuromuscular Junction / enzymology
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Phosphorylation
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Plant Lectins*
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Receptor Protein-Tyrosine Kinases / metabolism
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Receptors, Cholinergic / analysis*
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Receptors, Cholinergic / metabolism*
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Signal Transduction / physiology*
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Tyrosine / metabolism
Substances
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Agrin
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Cytoskeletal Proteins
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DAG1 protein, human
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Laminin
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Lectins
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Membrane Glycoproteins
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Plant Lectins
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Receptors, Cholinergic
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Vicia lectins
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Dystroglycans
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Tyrosine
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MUSK protein, human
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Receptor Protein-Tyrosine Kinases
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Neuraminidase
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N-Acetylneuraminic Acid
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Calcium