TY - JOUR
T1 - Strain hardening of actin filament networks
T2 - Regulation by the dynamic cross-linking protein α-actinin
AU - Xu, J.
AU - Tseng, Y.
AU - Wirtz, D.
PY - 2000/11/17
Y1 - 2000/11/17
N2 - Mechanical stresses applied to the plasma membrane of an adherent cell induces strain hardening of the cytoskeleton, i.e. the elasticity of the cytoskeleton increases with its deformation. Strain hardening is thought to mediate the transduction of mechanical signals across the plasma membrane through the cytoskeleton. Here, we describe the strain dependence of a model system consisting of actin filaments (F-actin), a major component of the cytoskeleton, and the F-actin cross-linking protein α-actinin, which localizes along contractile stress fibers and at focal adhesions. We show that the amplitude and rate of shear deformations regulate the resilience of F-actin networks. At low temperatures, for which the lifetime of binding of α-actinin to F-actin is long, F-actin/α-actinin networks exhibit strong strain hardening at short time scales and soften at long time scales. For F-actin networks in the absence of α-actinin or for F-actin/α-actinin networks at high temperatures, strain hardening appears only at very short time scales. We propose a model of strain hardening for F-actin networks, based on both the intrinsic rigidity of F-actin and dynamic topological constraints formed by the cross-linkers located at filaments entanglements. This model offers an explanation for the origin of strain hardening observed when shear stresses are applied against the cellular membrane.
AB - Mechanical stresses applied to the plasma membrane of an adherent cell induces strain hardening of the cytoskeleton, i.e. the elasticity of the cytoskeleton increases with its deformation. Strain hardening is thought to mediate the transduction of mechanical signals across the plasma membrane through the cytoskeleton. Here, we describe the strain dependence of a model system consisting of actin filaments (F-actin), a major component of the cytoskeleton, and the F-actin cross-linking protein α-actinin, which localizes along contractile stress fibers and at focal adhesions. We show that the amplitude and rate of shear deformations regulate the resilience of F-actin networks. At low temperatures, for which the lifetime of binding of α-actinin to F-actin is long, F-actin/α-actinin networks exhibit strong strain hardening at short time scales and soften at long time scales. For F-actin networks in the absence of α-actinin or for F-actin/α-actinin networks at high temperatures, strain hardening appears only at very short time scales. We propose a model of strain hardening for F-actin networks, based on both the intrinsic rigidity of F-actin and dynamic topological constraints formed by the cross-linkers located at filaments entanglements. This model offers an explanation for the origin of strain hardening observed when shear stresses are applied against the cellular membrane.
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U2 - 10.1074/jbc.M002377200
DO - 10.1074/jbc.M002377200
M3 - Article
C2 - 10954703
AN - SCOPUS:0034680846
SN - 0021-9258
VL - 275
SP - 35886
EP - 35892
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 46
ER -