Dynamic Role of Cross-Linking Proteins in Actin Rheology

We develop a computational model to compare the relative importance of unbinding and unfolding of actin cross-linking proteins (ACPs) in the dynamic properties of the actin cytoskeleton. We show that in the strain-stiffening regime with typical physiological and experimental strain rates, unbinding...

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Bibliographic Details
Main Authors: Kim, Taeyoon, Hwang, Wonmuk, Kamm, Roger Dale
Other Authors: Massachusetts Institute of Technology. Department of Biological Engineering
Format: Article
Language:en_US
Published: Elsevier 2014
Online Access:http://hdl.handle.net/1721.1/92328
https://orcid.org/0000-0002-7232-304X
Description
Summary:We develop a computational model to compare the relative importance of unbinding and unfolding of actin cross-linking proteins (ACPs) in the dynamic properties of the actin cytoskeleton. We show that in the strain-stiffening regime with typical physiological and experimental strain rates, unbinding events are predominant with negligible unfolding. ACPs unbound by greater forces experience larger displacements, with a tendency to rebind to different filaments. At constant strain, stress relaxes to physiological levels by unbinding only—not unfolding—of ACPs, which is consistent with experiments. Also, rebinding of ACPs dampens full relaxation of stress. When the network is allowed to return to a stress-free state after shear deformation, plastic deformation is observed only with unbinding. These results suggest that despite the possibility of unfolding, unbinding of ACPs is the major determinant for the rheology of the actin network.