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Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier
In mammalian neurons, the precise accumulation of sodium channels at the axonal initial segment (AIS) ensures action potential initiation. This accumulation precedes the immobilization of membrane proteins and lipids by a diffusion barrier at the AIS. Using single-particle tracking, we measured the...
Autores principales: | , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2958486/ https://www.ncbi.nlm.nih.gov/pubmed/20956383 http://dx.doi.org/10.1083/jcb.201003042 |
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author | Brachet, Anna Leterrier, Christophe Irondelle, Marie Fache, Marie-Pierre Racine, Victor Sibarita, Jean-Baptiste Choquet, Daniel Dargent, Bénédicte |
author_facet | Brachet, Anna Leterrier, Christophe Irondelle, Marie Fache, Marie-Pierre Racine, Victor Sibarita, Jean-Baptiste Choquet, Daniel Dargent, Bénédicte |
author_sort | Brachet, Anna |
collection | PubMed |
description | In mammalian neurons, the precise accumulation of sodium channels at the axonal initial segment (AIS) ensures action potential initiation. This accumulation precedes the immobilization of membrane proteins and lipids by a diffusion barrier at the AIS. Using single-particle tracking, we measured the mobility of a chimeric ion channel bearing the ankyrin-binding motif of the Nav1.2 sodium channel. We found that ankyrin G (ankG) limits membrane diffusion of ion channels when coexpressed in neuroblastoma cells. Site-directed mutants with decreased affinity for ankG exhibit increased diffusion speeds. In immature hippocampal neurons, we demonstrated that ion channel immobilization by ankG is regulated by protein kinase CK2 and occurs as soon as ankG accumulates at the AIS of elongating axons. Once the diffusion barrier is formed, ankG is still required to stabilize ion channels. In conclusion, our findings indicate that specific binding to ankG constitutes the initial step for Nav channel immobilization at the AIS membrane and precedes the establishment of the diffusion barrier. |
format | Text |
id | pubmed-2958486 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-29584862011-04-18 Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier Brachet, Anna Leterrier, Christophe Irondelle, Marie Fache, Marie-Pierre Racine, Victor Sibarita, Jean-Baptiste Choquet, Daniel Dargent, Bénédicte J Cell Biol Research Articles In mammalian neurons, the precise accumulation of sodium channels at the axonal initial segment (AIS) ensures action potential initiation. This accumulation precedes the immobilization of membrane proteins and lipids by a diffusion barrier at the AIS. Using single-particle tracking, we measured the mobility of a chimeric ion channel bearing the ankyrin-binding motif of the Nav1.2 sodium channel. We found that ankyrin G (ankG) limits membrane diffusion of ion channels when coexpressed in neuroblastoma cells. Site-directed mutants with decreased affinity for ankG exhibit increased diffusion speeds. In immature hippocampal neurons, we demonstrated that ion channel immobilization by ankG is regulated by protein kinase CK2 and occurs as soon as ankG accumulates at the AIS of elongating axons. Once the diffusion barrier is formed, ankG is still required to stabilize ion channels. In conclusion, our findings indicate that specific binding to ankG constitutes the initial step for Nav channel immobilization at the AIS membrane and precedes the establishment of the diffusion barrier. The Rockefeller University Press 2010-10-18 /pmc/articles/PMC2958486/ /pubmed/20956383 http://dx.doi.org/10.1083/jcb.201003042 Text en © 2010 Brachet et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/). |
spellingShingle | Research Articles Brachet, Anna Leterrier, Christophe Irondelle, Marie Fache, Marie-Pierre Racine, Victor Sibarita, Jean-Baptiste Choquet, Daniel Dargent, Bénédicte Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title | Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title_full | Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title_fullStr | Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title_full_unstemmed | Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title_short | Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
title_sort | ankyrin g restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2958486/ https://www.ncbi.nlm.nih.gov/pubmed/20956383 http://dx.doi.org/10.1083/jcb.201003042 |
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