Multiscale mechanics and temporal evolution of vimentin intermediate filament networks

The cytoskeleton, an intricate network of protein filaments, motor proteins, and cross-linkers, largely determines the mechanical properties of cells. Among the three filamentous components, F-actin, microtubules, and intermediate filaments (IFs), the IF network is by far the most extensible and resilient to stress. We present a multiscale approach to disentangle the three main contributions to vimentin IF network mechanics-single-filament mechanics, filament length, and interactions between filaments- including their temporal evolution. Combining particle tracking, quadruple optical trapping, and computational modeling, we derive quantitative information on the strength and kinetics of filament interactions. Specifically, we find that hydrophobic contributions to network mechanics enter mostly via filamentelongation kinetics, whereas electrostatics have a direct influence on filament-filament interactions.

Automated summary

The mechanical properties of cells are largely determined by the cytoskeleton, with the intermediate filament network being the most extensible and stress-resilient. A multiscale approach is used to analyze the contributions of single-filament mechanics, filament length, and interactions between filaments to vimentin IF network mechanics. Hydrophobic contributions primarily affect filament elongation kinetics, while electrostatics influence filament-filament interactions.