Measuring and modeling polymer gradients argues that spindle microtubules regulate their own nucleation

ORAL

Abstract

Spindle microtubules are nucleated by accessory proteins whose activity is
spatially regulated. It was shown that many spindle assembly factors bind
microtubules. Here, we investigate whether binding microtubules changes the
activity of nucleators. To study this issue, we use novel FLIM-FRET measurements
to map the concentration of microtubules and monomeric tubulin in and around the
spindle. We find that oligomeric tubulin is constrained to the spindle, with no
detectable gradient around it. This argues that microtubule nucleation is
restricted to the spindle. Using mathematical modelling we demonstrate that this
is indicative of a feedback from microtubule binding to nucleator activity. Our
results strongly suggest that nucleators binding to microtubules stimulates
their activity.

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Presenters

  • Sebastian Fuerthauer

    Flatiron Institute, Simons Foundation

Authors

  • Bryan Kaye

    SEAS, Harvard University

  • olivia steihl

    SEAS, Harvard University

  • Peter Foster

    Dept. of Physics, MIT, SEAS, Harvard University

  • Michael Shelley

    Center for Computational Biology, Simons Foundation; Courant Institute of Mathematical Science, New York University, New York University, Courant Institute/Flatiron Institute, Center for Computational Biology, Flatiron Institute, Simons Foundation, Flatiron Institute, Simons Foundation, Center for Computational Biology, Flatiron Institute, Flatiron Institute, CCB, Flatiron Institute

  • Daniel Needleman

    School of Engineering, Harvard University, SEAS, Harvard University, MCB/SEAS, Harvard University

  • Sebastian Fuerthauer

    Flatiron Institute, Simons Foundation