Spatiotemporal organization of branched microtubule networks.

TitleSpatiotemporal organization of branched microtubule networks.
Publication TypeJournal Article
Year of Publication2019
AuthorsThawani, A, Stone, HA, Shaevitz, JW, Petry, S
Date Published2019 May 08
KeywordsAnimals, Cell Cycle Proteins, Chromosome Segregation, Microtubule-Associated Proteins, Microtubule-Organizing Center, Microtubules, Protein Binding, Spindle Apparatus, Tubulin, Xenopus laevis, Xenopus Proteins

<p>To understand how chromosomes are segregated, it is necessary to explain the precise spatiotemporal organization of microtubules (MTs) in the mitotic spindle. We use egg extracts to study the nucleation and dynamics of MTs in branched networks, a process that is critical for spindle assembly. Surprisingly, new branched MTs preferentially originate near the minus-ends of pre-existing MTs. A sequential reaction model, consisting of deposition of nucleation sites on an existing MT, followed by rate-limiting nucleation of branches, reproduces the measured spatial profile of nucleation, the distribution of MT plus-ends and tubulin intensity. By regulating the availability of the branching effectors TPX2, augmin and γ-TuRC, combined with single-molecule observations, we show that first TPX2 is deposited on pre-existing MTs, followed by binding of augmin/γ-TuRC to result in the nucleation of branched MTs. In sum, regulating the localization and kinetics of nucleation effectors governs the architecture of branched MT networks.</p>

Alternate JournalElife
PubMed ID31066674
PubMed Central IDPMC6519983
Grant List2014-40376 / / David and Lucile Packard Foundation / International
1DP2GM123493-01 / GM / NIGMS NIH HHS / United States
PHY-1734030 / / National Science Foundation / International
00027340 / / Pew Charitable Trusts / International
DP2 GM123493 / GM / NIGMS NIH HHS / United States
17PRE33660328 / / American Heart Association / International