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Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi

Noncentrosomal microtubule (MT) nucleation at the Golgi generates MT network asymmetry in motile vertebrate cells. Investigating the Golgi-derived MT (GDMT) distribution, we find that MT asymmetry arises from nonrandom nucleation sites at the Golgi (hotspots). Using computational simulations, we pro...

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Autores principales: Sanders, Anna A. W. M., Chang, Kevin, Zhu, Xiaodong, Thoppil, Roslin J., Holmes, William R., Kaverina, Irina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687021/
https://www.ncbi.nlm.nih.gov/pubmed/28931596
http://dx.doi.org/10.1091/mbc.E17-06-0425
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author Sanders, Anna A. W. M.
Chang, Kevin
Zhu, Xiaodong
Thoppil, Roslin J.
Holmes, William R.
Kaverina, Irina
author_facet Sanders, Anna A. W. M.
Chang, Kevin
Zhu, Xiaodong
Thoppil, Roslin J.
Holmes, William R.
Kaverina, Irina
author_sort Sanders, Anna A. W. M.
collection PubMed
description Noncentrosomal microtubule (MT) nucleation at the Golgi generates MT network asymmetry in motile vertebrate cells. Investigating the Golgi-derived MT (GDMT) distribution, we find that MT asymmetry arises from nonrandom nucleation sites at the Golgi (hotspots). Using computational simulations, we propose two plausible mechanistic models of GDMT nucleation leading to this phenotype. In the “cooperativity” model, formation of a single GDMT promotes further nucleation at the same site. In the “heterogeneous Golgi” model, MT nucleation is dramatically up-regulated at discrete and sparse locations within the Golgi. While MT clustering in hotspots is equally well described by both models, simulating MT length distributions within the cooperativity model fits the data better. Investigating the molecular mechanism underlying hotspot formation, we have found that hotspots are significantly smaller than a Golgi subdomain positive for scaffolding protein AKAP450, which is thought to recruit GDMT nucleation factors. We have further probed potential roles of known GDMT-promoting molecules, including γ-TuRC-mediated nucleation activator (γ-TuNA) domain-containing proteins and MT stabilizer CLASPs. While both γ-TuNA inhibition and lack of CLASPs resulted in drastically decreased GDMT nucleation, computational modeling revealed that only γ-TuNA inhibition suppressed hotspot formation. We conclude that hotspots require γ-TuNA activity, which facilitates clustered GDMT nucleation at distinct Golgi sites.
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spelling pubmed-56870212018-01-22 Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi Sanders, Anna A. W. M. Chang, Kevin Zhu, Xiaodong Thoppil, Roslin J. Holmes, William R. Kaverina, Irina Mol Biol Cell Brief Reports Noncentrosomal microtubule (MT) nucleation at the Golgi generates MT network asymmetry in motile vertebrate cells. Investigating the Golgi-derived MT (GDMT) distribution, we find that MT asymmetry arises from nonrandom nucleation sites at the Golgi (hotspots). Using computational simulations, we propose two plausible mechanistic models of GDMT nucleation leading to this phenotype. In the “cooperativity” model, formation of a single GDMT promotes further nucleation at the same site. In the “heterogeneous Golgi” model, MT nucleation is dramatically up-regulated at discrete and sparse locations within the Golgi. While MT clustering in hotspots is equally well described by both models, simulating MT length distributions within the cooperativity model fits the data better. Investigating the molecular mechanism underlying hotspot formation, we have found that hotspots are significantly smaller than a Golgi subdomain positive for scaffolding protein AKAP450, which is thought to recruit GDMT nucleation factors. We have further probed potential roles of known GDMT-promoting molecules, including γ-TuRC-mediated nucleation activator (γ-TuNA) domain-containing proteins and MT stabilizer CLASPs. While both γ-TuNA inhibition and lack of CLASPs resulted in drastically decreased GDMT nucleation, computational modeling revealed that only γ-TuNA inhibition suppressed hotspot formation. We conclude that hotspots require γ-TuNA activity, which facilitates clustered GDMT nucleation at distinct Golgi sites. The American Society for Cell Biology 2017-11-07 /pmc/articles/PMC5687021/ /pubmed/28931596 http://dx.doi.org/10.1091/mbc.E17-06-0425 Text en © 2017 Sanders 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 for Cell Biology.
spellingShingle Brief Reports
Sanders, Anna A. W. M.
Chang, Kevin
Zhu, Xiaodong
Thoppil, Roslin J.
Holmes, William R.
Kaverina, Irina
Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title_full Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title_fullStr Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title_full_unstemmed Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title_short Nonrandom γ-TuNA-dependent spatial pattern of microtubule nucleation at the Golgi
title_sort nonrandom γ-tuna-dependent spatial pattern of microtubule nucleation at the golgi
topic Brief Reports
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687021/
https://www.ncbi.nlm.nih.gov/pubmed/28931596
http://dx.doi.org/10.1091/mbc.E17-06-0425
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