Spatial Variation of Microtubule Depolymerization in Large Asters Suggests Regulation by MAP Depletion
Spatial Variation of Microtubule Depolymerization in Large Asters Suggests Regulation by MAP Depletion
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.
Ishihara Keisuke、Pelletier James F.、Loose Martin、Brugu¨|s Jan、Caldas Paulo、Decker Franziska、Mitchison Timothy J.
Max Planck Institute of Molecular Cell Biology and Genetics||Max Planck Institute for the Physics of Complex Systems||Center for Systems Biology Dresden||Cluster of Excellence Physics of LifeDepartment of Systems Biology, Harvard Medical School||Cell Division Group, Marine Biological Laboratory||Department of Physics, Massachusetts Institute of TechnologyInstitute of Science and Technology AustriaMax Planck Institute of Molecular Cell Biology and Genetics||Max Planck Institute for the Physics of Complex Systems||Center for Systems Biology Dresden||Cluster of Excellence Physics of LifeInstitute of Science and Technology AustriaMax Planck Institute of Molecular Cell Biology and Genetics||Max Planck Institute for the Physics of Complex Systems||Center for Systems Biology Dresden||Cluster of Excellence Physics of LifeDepartment of Systems Biology, Harvard Medical School||Cell Division Group, Marine Biological Laboratory
细胞生物学生物物理学
Ishihara Keisuke,Pelletier James F.,Loose Martin,Brugu¨|s Jan,Caldas Paulo,Decker Franziska,Mitchison Timothy J..Spatial Variation of Microtubule Depolymerization in Large Asters Suggests Regulation by MAP Depletion[EB/OL].(2025-03-28)[2025-06-18].https://www.biorxiv.org/content/10.1101/2020.06.26.172783.点此复制
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