Microtubule Sliding within the Bridging Fiber Pushes Kinetochore Fibers Apart to Segregate Chromosomes

Vukušić, Kruno and Buđa, Renata and Bosilj, Agneza and Milas, Ana and Pavin, Nenad and Tolić, Iva Marija (2017) Microtubule Sliding within the Bridging Fiber Pushes Kinetochore Fibers Apart to Segregate Chromosomes. Developmental Cell, 43 (1). pp. 11-23. ISSN 1534-5807

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During cell division, mitotic spindle microtubules segregate chromosomes by exerting forces on kinetochores. What forces drive chromosome segregation in anaphase remains a central question. The current model for anaphase in human cells includes shortening of kinetochore fibers and separation of spindle poles. Both processes require kinetochores to be linked with the poles. Here we show, by combining laser ablation, photoactivation, and theoretical modeling, that kinetochores can separate without any attachment to one spindle pole. This separation requires the bridging fiber, a microtubule bundle that connects sister kinetochore fibers. Bridging fiber microtubules in intact spindles slide apart with kinetochore fibers, indicating strong crosslinks between them. We conclude that sliding of microtubules within the bridging fibers drives pole separation and pushes kinetochore fibers poleward by the friction of passive crosslinks between these fibers. Thus, sliding within the bridging fiber works together with the shortening of kinetochore fibers to segregate chromosomes.

Item Type: Article
Keywords: mitotic spindle, laser ablation, kinetochore microtubules, overlap microtubules, chromosome segregation, anaphase, bridging microtubules, anaphase model, pole separation, mitosis
Date: 2017
Subjects: NATURAL SCIENCES > Mathematics
Additional Information: © 2017 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). This work was funded by the European Research Council (ERC, GA number 647077).
Divisions: Faculty of Science > Department of Physics
Project code: 647077
Publisher: Elsevier
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 20 Nov 2017 09:09
Last Modified: 20 Nov 2017 09:09
URI: http://digre.pmf.unizg.hr/id/eprint/5665

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