Research article summary (published 13 Jun 1996):

Neural agrin activates a high-affinity receptor in C2 muscle cells that is unresponsive to muscle agrin.

Full Abstract

During synaptogenesis, agrin, released by motor nerves, causes the clustering of acetylcholine receptors (AChRs) in the skeletal muscle membrane. Although muscle alpha-dystroglycan has been postulated to be the receptor for the activity of agrin, previous experiments have revealed a discrepancy between the biological activity of soluble fragments of two isoforms of agrin produced by nerves and muscles, respectively, and their ability to bind alpha-dystroglycan. We have determined the specificity of the signaling receptor by investigating whether muscle agrin can block the activity of neural agrin on intact C2 myotubes. We find that a large excess of muscle agrin failed to inhibit either the number of AChR clusters or the phosphorylation of the AChR induced by picomolar concentrations of neural agrin. These results indicate that neural, but not muscle, agrin interacts with the signaling receptor. Muscle agrin did block the binding of neural agrin to isolated alpha-dystroglycan, however, suggesting either that alpha-dystroglycan is not the signaling receptor or that its properties in the membrane are altered. Direct assay of the binding of muscle or neural agrin to intact myotubes revealed only low-affinity binding. We conclude that the signaling receptor for agrin is a high-affinity receptor that is highly specific for the neural form.

Author information

Author/s: Bowen, D C (DC); Sugiyama, J (J); Ferns, M (M); Hall, Z W (ZW);

Affiliation: Regeneron Pharmaceuticals, Tarrytown, New York 10591, USA.

Journal and publication information

Publication Type: Journal Article; Research Support, U.S. Gov't, P.H.S.

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in UNITED STATES. (Language: eng)

Reference: 1996-Jun; vol 16 (issue 12) : pp 3791-7

Dates: Created 1996/07/30; Completed 1996/07/30; Revised 2008/11/21;

PMID: 8656273, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Agrin - chemistry; metabolism; pharmacology Animals Binding, Competitive - physiology Cell Line - chemistry; physiology Collodion Cytoskeletal Proteins - drug effects; metabolism Dystroglycans Dystrophin - drug effects; metabolism Isomerism Membrane Glycoproteins - drug effects; metabolism Mice

Mice Muscle Fibers, Skeletal - chemistry; metabolism; physiology Muscle, Skeletal - cytology Neuromuscular Junction - chemistry; physiology Phosphorylation Rats Receptors, Cholinergic - drug effects; metabolism; ultrastructure Recombinant Proteins - metabolism; pharmacology Sensitivity and Specificity Signal Transduction - physiology Torpedo

Associated Chemicals: Agrin (0) ; Cytoskeletal Proteins (0) ; Dystrophin (0) ; Membrane Glycoproteins (0) ; Receptors, Cholinergic (0) ; Recombinant Proteins (0) ; Dystroglycans (146888-27-9) ; Collodion (9004-70-0)

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