Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session K07: Intracellular Transport II: Transport at the Cellular Scale
3:00 PM–6:00 PM,
Tuesday, March 15, 2022
Room: McCormick Place W-179A
Sponsoring Unit: DBIO
Chair: Lena Koslover, University of California San Diego
Abstract: K07.00013 : Large deformations in the cytoplasm and cytoskeleton plasticity
5:48 PM–6:00 PM
David A Weitz
In this experiment work, we use an electrical magnetic tweezer to pull ferromagnetic particles through the cytoplasm. We induce large deformations and measure the plasticity of the cytoplasm. Further, we visualize how fluorescently-tagged cytoskeleton filaments: microtubules and vimentin reorganize themselves during this process. We find that the strain rate of large deformations has a distinct limit, independent of the applied force. This strain rate limit is dictated by the cytoskeleton dynamics. It can be altered by chemical treatments that either change the cytoskeleton density or inhibit the cytoskeleton dynamics.
We were also able to differentiate the role of each filament type. In the mouse embryonic fibroblast cell line, we find the microtubules and the intermediate filaments are important in the cytoplasm plastic deformation due to their abundance. In addition, they act synergistically to generate deformation resistance: removal of either filament completely changes the physics of the large deformation.
This research joins two longtime biophysics concepts together: the capacity of the cell to deform over time,e.g. cargo transport, cell migration, cell division, and the cytoskeleton dynamics. We hope this study can enrich the mechanical and physical understanding of the complicated and fascinating cellular biosystem.
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