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Nat Commun. 2018 Nov 23;9(1):4948. doi: 10.1038/s41467-018-07413-5.

Entropy production rate is maximized in non-contractile actomyosin.

Author information

1
Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA.
2
Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA.
3
Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA.
4
Department of Physics & Astronomy, and Department of Biology, University of Rochester, Rochester, NY, 14627, USA.
5
Physics Department, University of Northern Iowa, Cedar Falls, IA, 50614, USA.
6
Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, Gower Street, London, WC1E 6BT, UK. shiladitya.banerjee@ucl.ac.uk.
7
Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA. michael.murrell@yale.edu.
8
Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA. michael.murrell@yale.edu.
9
Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA. michael.murrell@yale.edu.

Abstract

The actin cytoskeleton is an active semi-flexible polymer network whose non-equilibrium properties coordinate both stable and contractile behaviors to maintain or change cell shape. While myosin motors drive the actin cytoskeleton out-of-equilibrium, the role of myosin-driven active stresses in the accumulation and dissipation of mechanical energy is unclear. To investigate this, we synthesize an actomyosin material in vitro whose active stress content can tune the network from stable to contractile. Each increment in activity determines a characteristic spectrum of actin filament fluctuations which is used to calculate the total mechanical work and the production of entropy in the material. We find that the balance of work and entropy does not increase monotonically and the entropy production rate is maximized in the non-contractile, stable state of actomyosin. Our study provides evidence that the origins of entropy production and activity-dependent dissipation relate to disorder in the molecular interactions between actin and myosin.

PMID:
30470750
PMCID:
PMC6251913
DOI:
10.1038/s41467-018-07413-5
[Indexed for MEDLINE]
Free PMC Article

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