Single Actin Bundle Rheology

Molecules

卷:22

Dan Strehle¹  Martin Glaser¹  Tom Golde¹  Josef A. Käs¹  Carsten Schuldt¹  Jörg Schnauß¹  Paul Mollenkopf¹ 

[1] Faculty of Physics and Earth Sciences, Peter Debye Institute, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany;

关键词: biopolymers;    actin;    bundles;    optical tweezers;    rheology;    mechanical properties;    dynamics;   

DOI  :  10.3390/molecules22101804

来源: DOAJ

【 摘 要 】

Bundled actin structures play an essential role in the mechanical response of the actin cytoskeleton in eukaryotic cells. Although responsible for crucial cellular processes, they are rarely investigated in comparison to single filaments and isotropic networks. Presenting a highly anisotropic structure, the determination of the mechanical properties of individual bundles was previously achieved through passive approaches observing bending deformations induced by thermal fluctuations. We present a new method to determine the bending stiffness of individual bundles, by measuring the decay of an actively induced oscillation. This approach allows us to systematically test anisotropic, bundled structures. Our experiments revealed that thin, depletion force-induced bundles behave as semiflexible polymers and obey the theoretical predictions determined by the wormlike chain model. Thickening an individual bundle by merging it with other bundles enabled us to study effects that are solely based on the number of involved filaments. These thicker bundles showed a frequency-dependent bending stiffness, a behavior that is inconsistent with the predictions of the wormlike chain model. We attribute this effect to internal processes and give a possible explanation with regard to the wormlike bundle theory.

【 授权许可】

Unknown