Spindles and active vortices

David A. Head, W. J. Briels, Gerhard Gompper

    Research output: Chapter in Book/Report/Conference proceedingChapterAcademicpeer-review


    Robust self-organization of subcellular structures is a key principle governing the dynamics and evolution of cellular life. In fission yeast cells undergoing division, the mitotic spindle spontaneously emerges from the interaction of microtubules, motor proteins and the confining cell walls, and asters and vortices have been observed to self-assemble in quasi-two dimensional microtubule-kinesin assays. There is no clear microscopic picture of the role of the active motors driving this pattern formation, and the relevance of continuum modeling to filament-scale structures remains uncertain. Here results of numerical simulations of a discrete filament-motor protein model confined to a pressurised cylindrical box. Stable spindles, nematic configurations, asters and high-density semi-asters spontaneously emerge, the latter pair having also been observed in cytosol confined within emulsion droplets. State diagrams are presented delineating each stationary state as the pressure, motor speed, and motor density are varied. The parameter regime where vortices form exhibiting collective rotation of all filaments have a finite life-time before contracting to a semi-aster. The quantifying the distribution of life-times suggests this contraction is a Poisson process. Equivalent systems with fixed volume exhibit persistent vortices with stochastic switching in the direction of rotation, with switching times obeying similar statistics to contraction times in pressurised systems. Furthermore, we show that increasing the detachment rate of motors from filament plus-ends can both destroy vortices and turn some asters into vortices.

    Original languageEnglish
    Title of host publicationTrends in Biophysics
    Subtitle of host publicationFrom Cell Dynamics Toward Multicellular Growth Phenomena
    PublisherApple Academic Press
    Number of pages23
    ISBN (Electronic)9781466584105
    ISBN (Print)9781926895369
    Publication statusPublished - 1 Jan 2013


    • Eukaryotic cells
    • Filamentous proteins
    • Fission yeast cells
    • Spindles
    • Steady-States


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