Dynamic Role of Cross-Linking Proteins in Actin Rheology
Author(s)Kim, Taeyoon; Hwang, Wonmuk; Kamm, Roger Dale
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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.
DepartmentMassachusetts Institute of Technology. Department of Biological Engineering; Massachusetts Institute of Technology. Department of Mechanical Engineering
Kim, Taeyoon, Wonmuk Hwang, and Roger D. Kamm. “Dynamic Role of Cross-Linking Proteins in Actin Rheology.” Biophysical Journal 101, no. 7 (October 2011): 1597–1603. © 2011 Biophysical Society.
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