A mechanism for acetylcholine receptor clustering distinct from agrin signaling.
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.
Grow
W A
WA
Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, AZ, USA. wgrow@online.emich.edu
Ferns
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Gordon
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D018171:Agrin / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000378:metabolism; D049030:Dystroglycans; D007797:Laminin / Q000378:metabolism; D037102:Lectins / Q000378:metabolism / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000737:chemistry* / Q000166:cytology / Q000201:enzymology; D010766:Phosphorylation; D037121:Plant Lectins; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000032:analysis* / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism
D018171:Agrin; D003598:Cytoskeletal Proteins; C483081:DAG1 protein, human; D007797:Laminin; D037102:Lectins; D008562:Membrane Glycoproteins; D037121:Plant Lectins; D011950:Receptors, Cholinergic; C042242:Vicia lectins; D049030:Dystroglycans; D014443:Tyrosine; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D002118:Calcium