Active restructuring of cytoskeleton composites leads to increased mechanical stiffness, memory, and heterogeneity

@inproceedings{Sheung2021ActiveRO,
  title={Active restructuring of cytoskeleton composites leads to increased mechanical stiffness, memory, and heterogeneity},
  author={Janet Y Sheung and Daisy H. Achiriloaie and Karthik Reddy Peddireddy and Gloria Lee and Michael J Rust and Moumita Das and Jennifer L. Ross and Rae M. Robertson-Anderson},
  year={2021}
}
The composite cytoskeleton, comprising interacting networks of semiflexible actin and rigid microtubules, actively generates forces and restructures using motor proteins such as myosins to enable key mechanical processes including cell motility and mitosis. Yet, how motor-driven activity alters the mechanics of cytoskeleton composites remains an open challenge. Here, we perform optical tweezers microrheology on actin-microtubule composites driven by myosin II motors to show that motor activity… 
2 Citations

Figures from this paper

Multiscale architecture: Mechanics of composite cytoskeletal networks

TLDR
This review discusses the work on networks consisting of one, two, or all three types of filaments, entangled or cross-linked, and considers active elements such as molecular motors and dynamically growing filaments.

DNA topology dictates emergent bulk elasticity and hindered macromolecular diffusion in DNA-dextran composites

Polymer architecture plays critical roles in both bulk rheological properties and microscale macromolecular dynamics in entangled polymer solutions and composites. Ring polymers, in particular, have…

References

SHOWING 1-10 OF 34 REFERENCES

Varying crosslinking motifs drive the mesoscale mechanics of actin-microtubule composites

The cytoskeleton dynamically tunes its mechanical properties by altering the interactions between semiflexible actin filaments, rigid microtubules, and crosslinking proteins. Here, we use optical…

Non-monotonic dependence of stiffness on actin crosslinking in cytoskeleton composites.

TLDR
This work uses optical tweezers microrheology and fluorescence confocal microscopy to reveal the surprising ways in which actin crosslinking tunes the viscoelasticity and mobility of actin-microtubule composites from steady-state to the highly nonlinear regime.

Myosin-driven actin-microtubule networks exhibit self-organized contractile dynamics

TLDR
This work combines dynamic differential microscopy, particle image velocimetry, and particle tracking to show that both actin and microtubules undergo ballistic contraction with unexpectedly indistinguishable characteristics, suggesting that micro Tubules enable self-organized myosin-driven contraction by providing flexural rigidity and enhanced connectivity to actin networks.

An active biopolymer network controlled by molecular motors

TLDR
An active polymer network in which processive molecular motors control network elasticity is described and suggests that adherent cells exert mechanical control by operating in a nonlinear regime where cell stiffness is sensitive to changes in motor activity.

Co-entangled actin-microtubule composites exhibit tunable stiffening and power-law stress relaxation

We use optical tweezers microrheology and fluorescence microscopy to characterize the nonlinear mesoscale mechanics and mobility of in vitro co-entangled actin-microtubule composites. We create a…

Active contractility in actomyosin networks

TLDR
A microscopic dynamic model is presented that incorporates two essential aspects of actomyosin self-organization: the asymmetric load response of individual actin filaments and the correlated motor-driven events mimicking myosin-induced filament sliding.

Molecular motor-induced instabilities and cross linkers determine biopolymer organization.

TLDR
This work reports a mechanism whereby the molecular motor myosin II can cause near-instantaneous order-disorder transitions in reconstituted cytoskeletal actin solutions, and illustrates that the interplay between passive crosslinking and molecular motor activity plays a substantial role in dynamic cellular organization.

A quantitative analysis of contractility in active cytoskeletal protein networks.

TLDR
The results suggest that cellular contractility can be sensitively regulated by tuning the (local) activity of molecular motors and the cross-linker density and binding affinity.

Geometrical Origins of Contractility in Disordered Actomyosin Networks

TLDR
A mathematical model of the actin scaffold’s local two- or three-dimensional mechanics is developed and it is predicted that one mechanism dominates, whereby local deformations of theActin break the balance between contraction and extension.

Active multistage coarsening of actin networks driven by myosin motors

TLDR
It is proposed that the physical origin of this multistage aggregation is the highly asymmetric load response of actin filaments: they can support large tensions but buckle easily under piconewton compressive loads.