Kinesin 5-independent poleward flux of kinetochore microtubules in PtK1 cells

Lisa A. Cameron, Ge Yang, Daniela Cimini, Julie C. Canman, Olga Kisurina-Evgenieva, Alexey Khodjakov, Gaudenz Danuser, E. D. Salmon

Research output: Contribution to journalArticle

81 Scopus citations

Abstract

Forces in the spindle that align and segregate chromosomes produce a steady poleward flux of kinetochore microtubules (MTs [kMTs]) in higher eukaryotes. In several nonmammalian systems, flux is driven by the tetrameric kinesin Eg5 (kinesin 5), which slides antiparallel MTs toward their minus ends. However, we find that the inhibition of kinesin 5 in mammalian cultured cells (PtK1) results in only minor reduction in the rate of kMT flux from ∼0.7 to ∼0.5 μm/min, the same rate measured in monopolar spindles that lack antiparallel MTs. These data reveal that the majority of poleward flux of kMTs in these cells is not driven by Eg5. Instead, we favor a polar "pulling-in" mechanism in which a depolymerase localized at kinetochore fiber minus ends makes a major contribution to poleward flux. One candidate, Kif2a (kinesin 13), was detected at minus ends of fluxing kinetochore fibers. Kif2a remains associated with the ends of K fibers upon disruption of the spindle by dynein/dynactin inhibition, and these K fibers flux.

Original languageEnglish (US)
Pages (from-to)173-179
Number of pages7
JournalJournal of Cell Biology
Volume173
Issue number2
DOIs
StatePublished - Apr 24 2006

ASJC Scopus subject areas

  • Cell Biology

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    Cameron, L. A., Yang, G., Cimini, D., Canman, J. C., Kisurina-Evgenieva, O., Khodjakov, A., Danuser, G., & Salmon, E. D. (2006). Kinesin 5-independent poleward flux of kinetochore microtubules in PtK1 cells. Journal of Cell Biology, 173(2), 173-179. https://doi.org/10.1083/jcb.200601075