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Nebulin binding impedes mutant desmin filament assembly

Desmin intermediate filaments (DIFs) form an intricate meshwork that organizes myofibers within striated muscle cells. The mechanisms that regulate the association of desmin to sarcomeres and their role in desminopathy are incompletely understood. Here we compare the effect nebulin binding has on th...

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Autores principales: Baker, Laura K., Gillis, David C., Sharma, Sarika, Ambrus, Andy, Herrmann, Harald, Conover, Gloria M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3681697/
https://www.ncbi.nlm.nih.gov/pubmed/23615443
http://dx.doi.org/10.1091/mbc.E12-11-0840
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author Baker, Laura K.
Gillis, David C.
Sharma, Sarika
Ambrus, Andy
Herrmann, Harald
Conover, Gloria M.
author_facet Baker, Laura K.
Gillis, David C.
Sharma, Sarika
Ambrus, Andy
Herrmann, Harald
Conover, Gloria M.
author_sort Baker, Laura K.
collection PubMed
description Desmin intermediate filaments (DIFs) form an intricate meshwork that organizes myofibers within striated muscle cells. The mechanisms that regulate the association of desmin to sarcomeres and their role in desminopathy are incompletely understood. Here we compare the effect nebulin binding has on the assembly kinetics of desmin and three desminopathy-causing mutant desmin variants carrying mutations in the head, rod, or tail domains of desmin (S46F, E245D, and T453I). These mutants were chosen because the mutated residues are located within the nebulin-binding regions of desmin. We discovered that, although nebulin M160–164 bound to both desmin tetrameric complexes and mature filaments, all three mutants exhibited significantly delayed filament assembly kinetics when bound to nebulin. Correspondingly, all three mutants displayed enhanced binding affinities and capacities for nebulin relative to wild-type desmin. Electron micrographs showed that nebulin associates with elongated normal and mutant DIFs assembled in vitro. Moreover, we measured significantly delayed dynamics for the mutant desmin E245D relative to wild-type desmin in fluorescence recovery after photobleaching in live-cell imaging experiments. We propose a mechanism by which mutant desmin slows desmin remodeling in myocytes by retaining nebulin near the Z-discs. On the basis of these data, we suggest that for some filament-forming desmin mutants, the molecular etiology of desminopathy results from subtle deficiencies in their association with nebulin, a major actin-binding filament protein of striated muscle.
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spelling pubmed-36816972013-08-30 Nebulin binding impedes mutant desmin filament assembly Baker, Laura K. Gillis, David C. Sharma, Sarika Ambrus, Andy Herrmann, Harald Conover, Gloria M. Mol Biol Cell Articles Desmin intermediate filaments (DIFs) form an intricate meshwork that organizes myofibers within striated muscle cells. The mechanisms that regulate the association of desmin to sarcomeres and their role in desminopathy are incompletely understood. Here we compare the effect nebulin binding has on the assembly kinetics of desmin and three desminopathy-causing mutant desmin variants carrying mutations in the head, rod, or tail domains of desmin (S46F, E245D, and T453I). These mutants were chosen because the mutated residues are located within the nebulin-binding regions of desmin. We discovered that, although nebulin M160–164 bound to both desmin tetrameric complexes and mature filaments, all three mutants exhibited significantly delayed filament assembly kinetics when bound to nebulin. Correspondingly, all three mutants displayed enhanced binding affinities and capacities for nebulin relative to wild-type desmin. Electron micrographs showed that nebulin associates with elongated normal and mutant DIFs assembled in vitro. Moreover, we measured significantly delayed dynamics for the mutant desmin E245D relative to wild-type desmin in fluorescence recovery after photobleaching in live-cell imaging experiments. We propose a mechanism by which mutant desmin slows desmin remodeling in myocytes by retaining nebulin near the Z-discs. On the basis of these data, we suggest that for some filament-forming desmin mutants, the molecular etiology of desminopathy results from subtle deficiencies in their association with nebulin, a major actin-binding filament protein of striated muscle. The American Society for Cell Biology 2013-06-15 /pmc/articles/PMC3681697/ /pubmed/23615443 http://dx.doi.org/10.1091/mbc.E12-11-0840 Text en © 2013 Baker et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society of Cell Biology.
spellingShingle Articles
Baker, Laura K.
Gillis, David C.
Sharma, Sarika
Ambrus, Andy
Herrmann, Harald
Conover, Gloria M.
Nebulin binding impedes mutant desmin filament assembly
title Nebulin binding impedes mutant desmin filament assembly
title_full Nebulin binding impedes mutant desmin filament assembly
title_fullStr Nebulin binding impedes mutant desmin filament assembly
title_full_unstemmed Nebulin binding impedes mutant desmin filament assembly
title_short Nebulin binding impedes mutant desmin filament assembly
title_sort nebulin binding impedes mutant desmin filament assembly
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3681697/
https://www.ncbi.nlm.nih.gov/pubmed/23615443
http://dx.doi.org/10.1091/mbc.E12-11-0840
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