Actin crosslinker density tunes mesoscale mechanics in actin-microtubule composites

ORAL

Abstract

The physical interactions between semiflexible actin filaments, rigid microtubules and the suit of smaller proteins that crosslink both filaments, allows the cytoskeleton to precisely tune its structure and mechanics to enable a vast array of cellular processes such as cytokinesis. Here we use optical tweezers microrheology to determine how steric entanglements versus chemical crosslinking impacts the nonlinear mesoscale mechanics of actin-microtubule composites. We create co-polymerized and co-entangled composites of actin and microtubules with varying concentrations of actin crosslinkers. We optically drive microspheres through the crosslinked composites at speeds much faster than the relaxation rates and distances larger than network mesh size. We simultaneously measure the force the filaments exert on the microspheres during and following the strain. We map network stiffness, relaxation profiles, and spatial heterogeneities to the concentration of actin crosslinkers in composites.

*This work was funded by a NSF CAREER Award #1255446, a NIH NNIGMS Award #R15GM123420, and a W.M. Keck Foundation Research Grant.

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Presenters

  • Shea Ricketts

    • University of San Diego
    • Physics, University of San Diego

Authors

  • Shea Ricketts

    • University of San Diego
    • Physics, University of San Diego

  • Madison Francis

    • University of San Diego

  • Leila Farhadi

    • University of Massachusetts Amherst
    • University of Massachusetts, Amherst

  • Jacob Wales

    • Rochester Institute of Technology

  • Michael Rust

    • University of Chicago
    • Molecular Genetics and Cell Biology Institute for Genomics and Systems Biology, University of chicago

  • Moumita Das

    • School of Physics and Astronomy, Rochester Institute of Technology
    • Rochester Institute of Technology
    • physics, Rochester Instituted of Technology
    • Department of Physics, Rochester institute of technology

  • Jennifer Ross

    • University of Massachusetts Amherst
    • University of Massachusetts, Amherst
    • Department of Physics, University of Massachusetts, Amherst
    • Physics, University of Massachusetts Amherst

  • Rae Robertson-Anderson

    • University of San Diego
    • Physics, University of San Diego
    • Physics and Biophysics, University of San Diego