Depletion-Driven Morphological Control of Bundled Actin Networks

Fuente: arXiv
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Main Authors: Clarke, James, Cavanna, Francis, Crowell, Anne D., Melcher, Lauren, Houser, Justin R., Graham, Kristin, Green, Allison, Stachowiak, Jeanne C., Truskett, Thomas M., Milliron, Delia J., Rosales, Adrianne M., Das, Moumita, Alvarado, José
Format: Preprint
Published: 2022
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author Clarke, James
Cavanna, Francis
Crowell, Anne D.
Melcher, Lauren
Houser, Justin R.
Graham, Kristin
Green, Allison
Stachowiak, Jeanne C.
Truskett, Thomas M.
Milliron, Delia J.
Rosales, Adrianne M.
Das, Moumita
Alvarado, José
author_facet Clarke, James
Cavanna, Francis
Crowell, Anne D.
Melcher, Lauren
Houser, Justin R.
Graham, Kristin
Green, Allison
Stachowiak, Jeanne C.
Truskett, Thomas M.
Milliron, Delia J.
Rosales, Adrianne M.
Das, Moumita
Alvarado, José
contents The actin cytoskeleton is a semiflexible biopolymer network whose morphology is controlled by a wide range of biochemical and physical factors. Actin is known to undergo a phase transition from a single-filament state to a bundled state by the addition of polyethylene glycol (PEG) molecules in sufficient concentration. While the depletion interaction experienced by these biopolymers is well-known, the effect of changing the molecular weight of the depletant is less well understood. Here, we experimentally identify a phase transition in solutions of actin from networks of filaments to networks of bundles by varying the molecular weight of PEG polymers, while holding the concentration of these PEG polymers constant. We examine the states straddling the phase transition in terms of micro and macroscale properties. We find that the mesh size, bundle diameter, persistence length, and intra-bundle spacing between filaments across the line of criticality do not show significant differences, while the relaxation time, storage modulus, and degree of bundling change between the two states do show significant differences. Our results demonstrate the ability to tune actin network morphology and mechanics by controlling depletant size, a property which could be exploited to develop actin-based materials with switchable rigidity.
format Preprint
id arxiv_https___arxiv_org_abs_2205_01864
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Depletion-Driven Morphological Control of Bundled Actin Networks
Clarke, James
Cavanna, Francis
Crowell, Anne D.
Melcher, Lauren
Houser, Justin R.
Graham, Kristin
Green, Allison
Stachowiak, Jeanne C.
Truskett, Thomas M.
Milliron, Delia J.
Rosales, Adrianne M.
Das, Moumita
Alvarado, José
Soft Condensed Matter
Biological Physics
The actin cytoskeleton is a semiflexible biopolymer network whose morphology is controlled by a wide range of biochemical and physical factors. Actin is known to undergo a phase transition from a single-filament state to a bundled state by the addition of polyethylene glycol (PEG) molecules in sufficient concentration. While the depletion interaction experienced by these biopolymers is well-known, the effect of changing the molecular weight of the depletant is less well understood. Here, we experimentally identify a phase transition in solutions of actin from networks of filaments to networks of bundles by varying the molecular weight of PEG polymers, while holding the concentration of these PEG polymers constant. We examine the states straddling the phase transition in terms of micro and macroscale properties. We find that the mesh size, bundle diameter, persistence length, and intra-bundle spacing between filaments across the line of criticality do not show significant differences, while the relaxation time, storage modulus, and degree of bundling change between the two states do show significant differences. Our results demonstrate the ability to tune actin network morphology and mechanics by controlling depletant size, a property which could be exploited to develop actin-based materials with switchable rigidity.
title Depletion-Driven Morphological Control of Bundled Actin Networks
topic Soft Condensed Matter
Biological Physics
url https://arxiv.org/abs/2205.01864