Actin Filament Length Tunes Elasticity of Flexibly Cross-Linked Actin Networks

Abstract

Networks of the cytoskeletal biopolymer actin cross-linked by the compliant protein filamin form soft gels that stiffen dramatically under shear stress. We demonstrate that the elasticity of these networks shows a strong dependence on the mean length of the actin polymers, unlike networks with small, rigid cross-links. This behavior is in agreement with a model of rigid filaments connected by multiple flexible linkers.

The role of structure in the nonlinear mechanics of cross-linked semiflexible polymer networks

“…Future work can be aimed at elucidating the individual roles of fiber properties (e.g., d, L, l p , and E) and cross-linker properties (e.g., k cl and r 0 ), which will enable more quantitative comparison to other experimental and theoretical works. 22,24,28,51 These properties, or the distribution thereof, 21,52,53 are likely to affect the structural network response by varying the length-scale difference between the heterogeneous and the homogeneous scales.…”

Imperfect asymmetry: The mechanism governing asymmetric partitioning of damaged cellular components during mitosis

“…[63][64][65] Not all of these effects can be attributed to the role of actin in replicative rejuvenationclearly actin is also essential for maintaining cellular homeostasis, proper protein movement, and cytoplasmic organization. 66 However, the above-mentioned experiments clearly demonstrate an essential role for actin-based rejuvenation in maintaining cellular fitness. Hence, in looking for the mechanism of mammalian cell asymmetry, the cytoskeleton is an obvious target.…”

Cross-link debonding in actin networks - influence on mechanical properties

“…From typical properties of actin filaments found in the literature (Furuike et al, 2001;Kamm and Mofrad, 2006;Gardel and Nakamura, 2006;Gardel et al, 2004Gardel et al, , 2008, we choose to use a diameter of 6 nm and Young's modulus of 1.8 GPa. The filament length of this baseline model -the reference case to compare influence of parameter variation with -is set to what is typically found experimentally in reconstituted actin networks (Kasza et al, 2010;Xu et al, 2000;Nunnally et al, 1980), 15 μm. Of course, not all filaments can be expected to have an equal length -an exponential distribution is most commonly found in reconstituted networks.…”