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BetaIVSigma1 spectrin stabilizes the nodes of Ranvier and axon initial segments.
J. Cell Biol. 166, 983-990 (2004)
Saltatory electric conduction requires clustered voltage-gated sodium channels (VGSCs) at axon initial segments (AIS) and nodes of Ranvier (NR). A dense membrane undercoat is present at these sites, which is thought to be key for the focal accumulation of channels. Here, we prove that betaIVSigma1 spectrin, the only betaIV spectrin with an actin-binding domain, is an essential component of this coat. Specifically, betaIVSigma1 coexists with betaIVSigma6 at both AIS and NR, being the predominant spectrin at AIS. Removal of betaIVSigma1 alone causes the disappearance of the nodal coat, an increased diameter of the NR, and the presence of dilations filled with organelles. Moreover, in myelinated cochlear afferent fibers, VGSC and ankyrin G clusters appear fragmented. These ultrastructural changes can explain the motor and auditory neuropathies present in betaIVSigma1 -/- mice and point to the betaIVSigma1 spectrin isoform as a master-stabilizing factor of AIS/NR membranes.
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Publication type
Article: Journal article
Document type
Scientific Article
Language
english
Publication Year
2004
HGF-reported in Year
0
ISSN (print) / ISBN
0021-9525
e-ISSN
1540-8140
Journal
Journal of Cell Biology, The
Quellenangaben
Volume: 166,
Issue: 7,
Pages: 983-990
Publisher
Rockefeller University Press
Reviewing status
Peer reviewed
Institute(s)
Institute of Pancreatic Islet Research (IPI)
PubMed ID
15381686
Erfassungsdatum
2004-12-31