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Proc Natl Acad Sci U S A. 2012 Apr 24;109(17):6446-51. doi: 10.1073/pnas.1204205109. Epub 2012 Apr 9.

Active contractility in actomyosin networks.

Author information

  • 1Department of Physics, Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093, USA.

Abstract

Contractile forces are essential for many developmental processes involving cell shape change and tissue deformation. Recent experiments on reconstituted actomyosin networks, the major component of the contractile machinery, have shown that active contractility occurs above a threshold motor concentration and within a window of cross-link concentration. We present a microscopic dynamic model 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. Using computer simulations, we examine how the concentration and susceptibility of motors contribute to their collective behavior and interplay with the network connectivity to regulate macroscopic contractility. Our model is shown to capture the formation and dynamics of contractile structures and agree with the observed dependence of active contractility on microscopic parameters, including the contractility onset. Cooperative action of load-resisting motors in a force-percolating structure integrates local contraction/buckling events into a global contractile state via an active coarsening process, in contrast to the flow transition driven by uncorrelated kicks of susceptible motors.

PMID:
22493220
[PubMed - indexed for MEDLINE]
PMCID:
PMC3340076
Free PMC Article

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