Spatial Variation of Microtubule Depolymerization in Large Asters Suggests Regulation by MAP Depletion.

First Authors Keisuke Ishihara
Authors Keisuke Ishihara, Franziska Decker, Paulo Caldas, James F. Pelletier, Martin Loose, Jan Brugu├ęs, Timothy J. Mitchison
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Last Authors Timothy J. Mitchison
Journal Name bioRxiv (bioRxiv)
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Online Publication Date 2020-06-26
Abstract Microtubule plus end depolymerization rate is a potentially important target of physiological regulation, but it has been challenging to measure, so its role in spatial organization is poorly understood. Here we apply a method for tracking plus ends based on time difference imaging to measure depolymerization rates in large interphase asters growing in Xenopus egg extract. We observed strong spatial regulation of depolymerization rates, which were almost two-fold higher in the aster interior compared to the periphery, and much less regulation of polymerization or catastrophe rates. We interpret these data in terms of a limiting component model, where aster growth results in lower levels of soluble tubulin and MAPs in the interior cytosol compared to that at the periphery. The steady-state polymer fraction of tubulin was ~30%, so tubulin is not strongly depleted in the aster interior. We propose that the limiting component for microtubule assembly is a MAP that inhibits depolymerization, and that egg asters are tuned to low microtubule density.
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DOI 10.1101/2020.06.26.172783
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Created By herbst
Added Date 2020-10-28
Last Edited By herbst
Last Edited Date 2022-02-18 15:30:06.345
Library ID 7836
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