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Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine

Microtubule-targeting agents (MTAs), widely used as biological probes and chemotherapeutic drugs, bind directly to tubulin subunits and “kinetically stabilize” microtubules, suppressing the characteristic self-assembly process of dynamic instability. However, the molecular-level mechanisms of kineti...

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Autores principales: Castle, Brian T., McCubbin, Seth, Prahl, Louis S., Bernens, Jordan N., Sept, David, Odde, David J.
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/PMC5415019/
https://www.ncbi.nlm.nih.gov/pubmed/28298489
http://dx.doi.org/10.1091/mbc.E16-08-0567
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author Castle, Brian T.
McCubbin, Seth
Prahl, Louis S.
Bernens, Jordan N.
Sept, David
Odde, David J.
author_facet Castle, Brian T.
McCubbin, Seth
Prahl, Louis S.
Bernens, Jordan N.
Sept, David
Odde, David J.
author_sort Castle, Brian T.
collection PubMed
description Microtubule-targeting agents (MTAs), widely used as biological probes and chemotherapeutic drugs, bind directly to tubulin subunits and “kinetically stabilize” microtubules, suppressing the characteristic self-assembly process of dynamic instability. However, the molecular-level mechanisms of kinetic stabilization are unclear, and the fundamental thermodynamic and kinetic requirements for dynamic instability and its elimination by MTAs have yet to be defined. Here we integrate a computational model for microtubule assembly with nanometer-scale fluorescence microscopy measurements to identify the kinetic and thermodynamic basis of kinetic stabilization by the MTAs paclitaxel, an assembly promoter, and vinblastine, a disassembly promoter. We identify two distinct modes of kinetic stabilization in live cells, one that truly suppresses on-off kinetics, characteristic of vinblastine, and the other a “pseudo” kinetic stabilization, characteristic of paclitaxel, that nearly eliminates the energy difference between the GTP- and GDP-tubulin thermodynamic states. By either mechanism, the main effect of both MTAs is to effectively stabilize the microtubule against disassembly in the absence of a robust GTP cap.
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spelling pubmed-54150192017-07-16 Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine Castle, Brian T. McCubbin, Seth Prahl, Louis S. Bernens, Jordan N. Sept, David Odde, David J. Mol Biol Cell Articles Microtubule-targeting agents (MTAs), widely used as biological probes and chemotherapeutic drugs, bind directly to tubulin subunits and “kinetically stabilize” microtubules, suppressing the characteristic self-assembly process of dynamic instability. However, the molecular-level mechanisms of kinetic stabilization are unclear, and the fundamental thermodynamic and kinetic requirements for dynamic instability and its elimination by MTAs have yet to be defined. Here we integrate a computational model for microtubule assembly with nanometer-scale fluorescence microscopy measurements to identify the kinetic and thermodynamic basis of kinetic stabilization by the MTAs paclitaxel, an assembly promoter, and vinblastine, a disassembly promoter. We identify two distinct modes of kinetic stabilization in live cells, one that truly suppresses on-off kinetics, characteristic of vinblastine, and the other a “pseudo” kinetic stabilization, characteristic of paclitaxel, that nearly eliminates the energy difference between the GTP- and GDP-tubulin thermodynamic states. By either mechanism, the main effect of both MTAs is to effectively stabilize the microtubule against disassembly in the absence of a robust GTP cap. The American Society for Cell Biology 2017-05-01 /pmc/articles/PMC5415019/ /pubmed/28298489 http://dx.doi.org/10.1091/mbc.E16-08-0567 Text en © 2017 Castle 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 Articles
Castle, Brian T.
McCubbin, Seth
Prahl, Louis S.
Bernens, Jordan N.
Sept, David
Odde, David J.
Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title_full Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title_fullStr Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title_full_unstemmed Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title_short Mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
title_sort mechanisms of kinetic stabilization by the drugs paclitaxel and vinblastine
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5415019/
https://www.ncbi.nlm.nih.gov/pubmed/28298489
http://dx.doi.org/10.1091/mbc.E16-08-0567
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