Research article summary (published 29 Nov 2000):

The Agrin/MuSK signaling pathway is spatially segregated from the neuregulin/ErbB receptor signaling pathway at the neuromuscular junction.

Full Abstract

The neuregulin/erbB receptor and agrin/MuSK pathways are critical for communication between the nerve, muscle, and Schwann cell that establishes the precise topological arrangement at the vertebrate neuromuscular junction (NMJ). ErbB2, erbB3, and erbB4 as well as neuregulin, agrin, and MuSK are known to be concentrated at the NMJ. Here we have examined NMJs from gastrocnemius muscle of adult rat using immunofluorescence confocal microscopy to characterize in detail the distribution of these proteins relative to the distribution of acetylcholine receptors (AChRs). We have determined that erbB2 and erbB4 are enriched in the depths of the secondary junctional folds on the postsynaptic muscle membrane. In contrast, erbB3 at the NMJ was concentrated at presynaptic terminal Schwann cells. This distribution strongly argues that erbB2/erbB4 heterodimers are the functional postsynaptic neuregulin receptors of the NMJ. Neuregulin was localized to the axon terminal, secondary folds, and terminal Schwann cells, where it was in a position to signal through erbB receptors. MuSK was concentrated in the postsynaptic primary gutter region where it was codistributed with AChRs. Agrin was present at the axon terminal and in the basal lamina associated with the primary gutter region, but not in the secondary junctional folds. The differential distributions of the neuregulin and agrin signaling pathways argue against neuregulin and erbB receptors being localized to the NMJ via direct interactions with either agrin or MuSK.

Author information

Author/s: Trinidad, J C (JC); Fischbach, G D (GD); Cohen, J B (JB);

Affiliation: Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.

Grants: NS18458 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; 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: 2000-Dec; vol 20 (issue 23) : pp 8762-70

Dates: Created 2001/01/04; Completed 2001/02/08; Revised 2007/11/14;

PMID: 11102484, 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 - metabolism Animals Antigens, Differentiation - metabolism Fluorescent Antibody Technique Microscopy, Confocal Microscopy, Electron Muscle, Skeletal - cytology; metabolism Neuregulins - metabolism Neuromuscular Junction - metabolism; ultrastructure Presynaptic Terminals - metabolism; ultrastructure

Presynaptic Terminals - metabolism; ultrastructure Rats Rats, Sprague-Dawley Receptor Protein-Tyrosine Kinases - metabolism Receptor, Epidermal Growth Factor - metabolism Receptor, erbB-2 - metabolism Receptor, erbB-3 - metabolism Receptors, Cholinergic Schwann Cells - cytology; metabolism Signal Transduction - physiology

Associated Chemicals: Agrin (0) ; Antigens, Differentiation (0) ; Neuregulins (0) ; Receptors, Cholinergic (0) ; ERBB4 protein (EC 2.7.1.112) ; Receptor Protein-Tyrosine Kinases (EC 2.7.1.112) ; Receptor, Epidermal Growth Factor (EC 2.7.1.112) ; Receptor, erbB-2 (EC 2.7.1.112) ; Receptor, erbB-3 (EC 2.7.1.112) ; MUSK protein, human (EC 2.7.10.1)

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