Measuring Cohesion between Macromolecular Filaments One Pair at a Time: Depletion-Induced Microtubule Bundling

Hilitski, Feodor; Ward, Andrew; Cajamarca, Luis; Hagan, Michael F.; Grason, Gregory M.; Dogic, Zvonimir

doi:10.1103/physrevlett.114.138102

Cited by 67 publications

(63 citation statements)

References 60 publications

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“…Stress-induced weakening of the actin cytoskeleton by cross-linker breakage suggests that the active behaviour of the entire cell may result from the slow unbuckling of microtubules. In turn, this suggests an entropic origin of the effect, which has been previously reported for both actin and microtubules [58,78,[80][81][82][83][84]. Destabilizing microtubules resulted in a lack of relaxation, i.e.…”

Section: Microtubules Determine Cell Relaxation At Small Strainssupporting

confidence: 71%

Actin and microtubule networks contribute differently to cell response for small and large strains

et al. 2017

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Cytoskeletal filaments provide cells with mechanical stability and organization. The main key players are actin filaments and microtubules governing a cell's response to mechanical stimuli. We investigated the specific influences of these crucial components by deforming MCF-7 epithelial cells at small (5% deformation) and large strains (>5% deformation). To understand specific contributions of actin filaments and microtubules, we systematically studied cellular responses after treatment with cytoskeleton influencing drugs. Quantification with the microfluidic optical stretcher allowed capturing the relative deformation and relaxation of cells under different conditions. We separated distinctive deformational and relaxational contributions to cell mechanics for actin and microtubule networks for two orders of magnitude of drug dosages. Disrupting actin filaments via latrunculin A, for instance, revealed a strain-independent softening. Stabilizing these filaments by treatment with jasplakinolide yielded cell softening for small strains but showed no significant change at large strains. In contrast, cells treated with nocodazole to disrupt microtubules displayed a softening at large strains but remained unchanged at small strains. Stabilizing microtubules within the cells via paclitaxel revealed no significant changes for deformations at small strains, but concentration-dependent impact at large strains. This suggests that for suspended cells, the actin cortex is probed at small strains, while at larger strains; the whole cell is probed with a significant contribution from the microtubules.

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Section: Microtubules Determine Cell Relaxation At Small Strainssupporting

confidence: 71%

Actin and microtubule networks contribute differently to cell response for small and large strains

et al. 2017

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“…To apply the Asakura-Oosawa model, 42 flexible polymers like MC are typically treated as freely interpenetrating hard spheres of the radius R AO , which are excluded from the colloid surface by a thin layer of thickness R AO . 23,44 Here, if we consider the force of each kinesin as ∼5 pN, 45 the total force of kinesins interacting with each microtubule on the surface should be several tens of pN. Then the size of the depletion force was calculated as ∼0.11 pN which was almost comparable to that of PEG or MC reported in the previous literature.…”

Section: Resultssupporting

confidence: 52%

Depletion force induced collective motion of microtubules driven by kinesin

et al. 2015

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“…See Section 5.2 for an example of the further steps required to derive the final, ready‐to‐use expressions in case of vdW interactions. To give but one example for a recent experimental work, which could serve as the basis for the second option listed above, we refer to Reference measuring cohesive interactions between a single pair of microtubules. Postulating an SSIP and studying the global system response in numerical simulations could also be used as a verification of theoretical predictions for the system behavior.…”

Section: Application Of the General Ssip Approach To Specific Types Omentioning

confidence: 99%

A computational model for molecular interactions between curved slender fibers undergoing large 3D deformations with a focus on electrostatic, van der Waals, and repulsive steric forces

Grill

Wall

Meier

2020

Numerical Meth Engineering

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Summary This contribution proposes the first three‐dimensional (3D) beam‐beam interaction model for molecular interactions between curved slender fibers undergoing large deformations. While the general model is not restricted to a specific beam formulation, in the present work, it is combined with the geometrically exact beam theory and discretized via the finite element method. A direct evaluation of the total interaction potential for general 3D bodies requires the integration of contributions from molecule or charge distributions over the volumes of the interaction partners, leading to a six‐dimensional integral (two nested 3D integrals) that has to be solved numerically. Here, we propose a novel strategy to formulate reduced section‐section interaction laws for the resultant interaction potential between a pair of cross‐sections of two slender fibers such that only two one‐dimensional integrals along the fibers' length directions have to be solved numerically. This section‐section interaction potential (SSIP) approach yields a significant gain in efficiency, which is essential to enable the simulation of relevant time and length scales for many practical applications. In a first step, the generic structure of SSIP laws, which is suitable for the most general interaction scenario (eg, fibers with arbitrary cross‐section shape and inhomogeneous atomic/charge density within the cross‐section) is presented. Assuming circular, homogeneous cross‐sections, in a next step, specific analytical expressions for SSIP laws describing short‐range volume interactions (eg, van der Waals (vdW) or steric interactions) and long‐range surface interactions (eg, Coulomb interactions) are proposed. Besides ready‐to‐use expressions for the total interaction potential, also the resulting virtual work contributions, its finite element discretizations, as well as a suitable numerical regularization for the limit of zero separation are derived. The validity of the SSIP laws, as well as the accuracy and robustness of the general SSIP approach to beam‐beam interactions, is thoroughly verified by means of a set of numerical examples considering steric repulsion, electrostatic, or vdW adhesion.

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Measuring Cohesion between Macromolecular Filaments One Pair at a Time: Depletion-Induced Microtubule Bundling

Cited by 67 publications

References 60 publications

Actin and microtubule networks contribute differently to cell response for small and large strains

Actin and microtubule networks contribute differently to cell response for small and large strains

Depletion force induced collective motion of microtubules driven by kinesin

A computational model for molecular interactions between curved slender fibers undergoing large 3D deformations with a focus on electrostatic, van der Waals, and repulsive steric forces

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