Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network

Cells dynamically change their viscoelastic properties by restructuring networks of actin filaments in the cytoskeleton, enabling diverse mechanical processes such as mobility and apoptosis. This restructuring is modulated, in part, by actin-binding proteins, such as myosin II, as well as counterion...

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Autores principales:	Bekele J. Gurmessa, Michael J. Rust, Moumita Das, Jennifer L. Ross, Rae M. Robertson-Anderson
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	optical tweezers microrheology actin myosin microfluidics counterion condensation Physics QC1-999
Acceso en línea:	https://doaj.org/article/a3ea0d52cb9840bab76dc70a3a96f914
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spelling	oai:doaj.org-article:a3ea0d52cb9840bab76dc70a3a96f9142021-11-19T05:12:08ZSalt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network2296-424X10.3389/fphy.2021.760340https://doaj.org/article/a3ea0d52cb9840bab76dc70a3a96f9142021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fphy.2021.760340/fullhttps://doaj.org/toc/2296-424XCells dynamically change their viscoelastic properties by restructuring networks of actin filaments in the cytoskeleton, enabling diverse mechanical processes such as mobility and apoptosis. This restructuring is modulated, in part, by actin-binding proteins, such as myosin II, as well as counterions such as Mg2+ and K+. While high concentrations of Mg2+ can induce bundling and crosslinking of actin filaments, high concentrations of K+ destabilize myosin II minifilaments necessary to crosslink actin filaments. Here, we elucidate how the mechanics and structure of actomyosin networks evolve under competing effects of varying Mg2+ and K+ concentrations. Specifically, we couple microfluidics with optical tweezers microrheology to measure the time-varying linear viscoelastic moduli of actin networks crosslinked via myosin II as we cycle between low and high Mg2+ and K+ concentrations. Our complementary confocal imaging experiments correlate the time-varying viscoelastic properties with salt-mediated structural evolution. We find that the elastic modulus displays an intriguing non-monotonic time dependence in high-salt conditions, that correlates with structural changes, and that this process is irreversible, with the network evolving to a new steady-state as Mg2+ and K+ decrease back to their initial concentrations.Bekele J. GurmessaBekele J. GurmessaMichael J. RustMoumita DasJennifer L. RossRae M. Robertson-AndersonFrontiers Media S.A.articleoptical tweezersmicrorheologyactinmyosinmicrofluidicscounterion condensationPhysicsQC1-999ENFrontiers in Physics, Vol 9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	optical tweezers microrheology actin myosin microfluidics counterion condensation Physics QC1-999
spellingShingle	optical tweezers microrheology actin myosin microfluidics counterion condensation Physics QC1-999 Bekele J. Gurmessa Bekele J. Gurmessa Michael J. Rust Moumita Das Jennifer L. Ross Rae M. Robertson-Anderson Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
description	Cells dynamically change their viscoelastic properties by restructuring networks of actin filaments in the cytoskeleton, enabling diverse mechanical processes such as mobility and apoptosis. This restructuring is modulated, in part, by actin-binding proteins, such as myosin II, as well as counterions such as Mg2+ and K+. While high concentrations of Mg2+ can induce bundling and crosslinking of actin filaments, high concentrations of K+ destabilize myosin II minifilaments necessary to crosslink actin filaments. Here, we elucidate how the mechanics and structure of actomyosin networks evolve under competing effects of varying Mg2+ and K+ concentrations. Specifically, we couple microfluidics with optical tweezers microrheology to measure the time-varying linear viscoelastic moduli of actin networks crosslinked via myosin II as we cycle between low and high Mg2+ and K+ concentrations. Our complementary confocal imaging experiments correlate the time-varying viscoelastic properties with salt-mediated structural evolution. We find that the elastic modulus displays an intriguing non-monotonic time dependence in high-salt conditions, that correlates with structural changes, and that this process is irreversible, with the network evolving to a new steady-state as Mg2+ and K+ decrease back to their initial concentrations.
format	article
author	Bekele J. Gurmessa Bekele J. Gurmessa Michael J. Rust Moumita Das Jennifer L. Ross Rae M. Robertson-Anderson
author_facet	Bekele J. Gurmessa Bekele J. Gurmessa Michael J. Rust Moumita Das Jennifer L. Ross Rae M. Robertson-Anderson
author_sort	Bekele J. Gurmessa
title	Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
title_short	Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
title_full	Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
title_fullStr	Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
title_full_unstemmed	Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network
title_sort	salt-mediated stiffening, destruction, and resculpting of actomyosin network
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/a3ea0d52cb9840bab76dc70a3a96f914
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Salt-Mediated Stiffening, Destruction, and Resculpting of Actomyosin Network

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