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Quantitation of the distribution and flux of myosin-II during cytokinesis

BACKGROUND: During cytokinesis, the cell's equator contracts against the cell's global stiffness. Identifying the biochemical basis for these mechanical parameters is essential for understanding how cells divide. To achieve this goal, the distribution and flux of the cell division machiner...

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Autores principales: Robinson, Douglas N, Cavet, Guy, Warrick, Hans M, Spudich, James A
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2002
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC65686/
https://www.ncbi.nlm.nih.gov/pubmed/11860600
http://dx.doi.org/10.1186/1471-2121-3-4
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author Robinson, Douglas N
Cavet, Guy
Warrick, Hans M
Spudich, James A
author_facet Robinson, Douglas N
Cavet, Guy
Warrick, Hans M
Spudich, James A
author_sort Robinson, Douglas N
collection PubMed
description BACKGROUND: During cytokinesis, the cell's equator contracts against the cell's global stiffness. Identifying the biochemical basis for these mechanical parameters is essential for understanding how cells divide. To achieve this goal, the distribution and flux of the cell division machinery must be quantified. Here we report the first quantitative analysis of the distribution and flux of myosin-II, an essential element of the contractile ring. RESULTS: The fluxes of myosin-II in the furrow cortex, the polar cortex, and the cytoplasm were examined using ratio imaging of GFP fusion proteins expressed in Dictyostelium. The peak concentration of GFP-myosin-II in the furrow cortex is 1.8-fold higher than in the polar cortex and 2.0-fold higher than in the cytoplasm. The myosin-II in the furrow cortex, however, represents only 10% of the total cellular myosin-II. An estimate of the minimal amount of this motor needed to produce the required force for cell cleavage fits well with this 10% value. The cell may, therefore, regulate the amount of myosin-II sent to the furrow cortex in accordance with the amount needed there. Quantitation of the distribution and flux of a mutant myosin-II that is defective in phosphorylation-dependent thick filament disassembly confirms that heavy chain phosphorylation regulates normal recruitment to the furrow cortex. CONCLUSION: The analysis indicates that myosin-II flux through the cleavage furrow cortex is regulated by thick filament phosphorylation. Further, the amount of myosin-II observed in the furrow cortex is in close agreement with the amount predicted to be required from a simple theoretical analysis.
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spelling pubmed-656862002-02-26 Quantitation of the distribution and flux of myosin-II during cytokinesis Robinson, Douglas N Cavet, Guy Warrick, Hans M Spudich, James A BMC Cell Biol Research Article BACKGROUND: During cytokinesis, the cell's equator contracts against the cell's global stiffness. Identifying the biochemical basis for these mechanical parameters is essential for understanding how cells divide. To achieve this goal, the distribution and flux of the cell division machinery must be quantified. Here we report the first quantitative analysis of the distribution and flux of myosin-II, an essential element of the contractile ring. RESULTS: The fluxes of myosin-II in the furrow cortex, the polar cortex, and the cytoplasm were examined using ratio imaging of GFP fusion proteins expressed in Dictyostelium. The peak concentration of GFP-myosin-II in the furrow cortex is 1.8-fold higher than in the polar cortex and 2.0-fold higher than in the cytoplasm. The myosin-II in the furrow cortex, however, represents only 10% of the total cellular myosin-II. An estimate of the minimal amount of this motor needed to produce the required force for cell cleavage fits well with this 10% value. The cell may, therefore, regulate the amount of myosin-II sent to the furrow cortex in accordance with the amount needed there. Quantitation of the distribution and flux of a mutant myosin-II that is defective in phosphorylation-dependent thick filament disassembly confirms that heavy chain phosphorylation regulates normal recruitment to the furrow cortex. CONCLUSION: The analysis indicates that myosin-II flux through the cleavage furrow cortex is regulated by thick filament phosphorylation. Further, the amount of myosin-II observed in the furrow cortex is in close agreement with the amount predicted to be required from a simple theoretical analysis. BioMed Central 2002-02-08 /pmc/articles/PMC65686/ /pubmed/11860600 http://dx.doi.org/10.1186/1471-2121-3-4 Text en Copyright © 2002 Robinson et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.
spellingShingle Research Article
Robinson, Douglas N
Cavet, Guy
Warrick, Hans M
Spudich, James A
Quantitation of the distribution and flux of myosin-II during cytokinesis
title Quantitation of the distribution and flux of myosin-II during cytokinesis
title_full Quantitation of the distribution and flux of myosin-II during cytokinesis
title_fullStr Quantitation of the distribution and flux of myosin-II during cytokinesis
title_full_unstemmed Quantitation of the distribution and flux of myosin-II during cytokinesis
title_short Quantitation of the distribution and flux of myosin-II during cytokinesis
title_sort quantitation of the distribution and flux of myosin-ii during cytokinesis
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC65686/
https://www.ncbi.nlm.nih.gov/pubmed/11860600
http://dx.doi.org/10.1186/1471-2121-3-4
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