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Differential regulation of AChR clustering in the polar and equatorial region of murine muscle spindles.
Eur. J. Neurosci. 41, 69-78 (2015)
Intrafusal fibers of muscle spindles are innervated in the central region by afferent sensory axons and at both polar regions by efferent γ-motoneurons. We previously demonstrated that both neuron-muscle contact sites contain cholinergic synapse-like specialisation, including aggregates of the nicotinic acetylcholine receptor (AChR). In this study we tested the hypothesis that agrin and its receptor complex (consisting of LRP4 and the tyrosine kinase MuSK) are involved in the aggregation of AChRs in muscle spindles, similar to their role at the neuromuscular junction. We show that agrin, MuSK and LRP4 are concentrated at the contact site between the intrafusal fibers and the sensory- and γ-motoneuron, respectively, and that they are expressed in the cell bodies of proprioceptive neurons in dorsal root ganglia. Moreover, agrin and LRP4, but not MuSK, are expressed in γ-motoneuron cell bodies in the ventral horn of the spinal cord. In agrin- and in MuSK-deficient mice, AChR aggregates are absent from the polar regions. In contrast, the subcellular concentration of AChRs in the central region where the sensory neuron contacts the intrafusal muscle fiber is apparently unaffected. Skeletal muscle-specific expression of miniagrin in agrin(-/-) mice in vivo is sufficient to restore the formation of γ-motoneuron endplates. These results show that agrin and MuSK are major determinants during the formation of γ-motoneuron endplates but appear dispensable for the aggregation of AChRs at the central region. Our results therefore suggest different molecular mechanisms for AChR clustering within two domains of intrafusal fibers.
Impact Factor
Scopus SNIP
Web of Science
Times Cited
Times Cited
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Cited By
Cited By
Altmetric
3.181
1.036
16
18
Anmerkungen
Besondere Publikation
Auf Hompepage verbergern
Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
Agrin ; Intrafusal Fiber ; Muscle-specific Kinase ; Proprioception ; Synaptogenesis; Gamma-motor-neurons; Neuromuscular-junction Formation; Heparan-sulfate Proteoglycan; Mutant Mice; Spinal-cord; Acetylcholine-receptors; Myotendinous Junction; Neurite Outgrowth; Sensory Neurons; Agrin
Sprache
Veröffentlichungsjahr
2015
HGF-Berichtsjahr
2015
ISSN (print) / ISBN
0953-816X
e-ISSN
1460-9568
Zeitschrift
European Journal of Neuroscience
Quellenangaben
Band: 41,
Heft: 1,
Seiten: 69-78
Verlag
Wiley
Verlagsort
Hoboken
Begutachtungsstatus
Peer reviewed
Institut(e)
Institute of Stem Cell Research (ISF)
POF Topic(s)
30204 - Cell Programming and Repair
Forschungsfeld(er)
Stem Cell and Neuroscience
PSP-Element(e)
G-500800-001
PubMed ID
25377642
WOS ID
WOS:000347333200008
Scopus ID
85007038207
Erfassungsdatum
2015-01-01