Rupture Mechanics of Vimentin Intermediate Filament Tetramers

Abstract

Together with the globular proteins, microtubules and microfilaments, intermediate filaments are one of the three major components of the cytoskeleton in eukaryotic cells. They consist of a dimeric coiled-coil building block, assembled in a very precise, hierarchical fashion into tetramers, forming filaments with characteristic dimensions on the order of several micrometers. Here we focus on the theoretical analysis of the deformation mechanics of vimentin intermediate filaments, a type of intermediate filament expressed in leukocytes, blood vessel endothelial cells, some epithelial cells, and mesenchymal cells such as fibroblasts. The main contribution of this paper is the study of the rupture mechanics of intermediate filament tetramers, representing an assembly of two dimers, by utilizing a statistical Bell model adapted to describe the rupture dynamics of intermediate filaments. Possible deformation mechanisms, including interdimer sliding and uncoiling of the dimer, are illustrated in light of the interdimer adhesion and dimer stability. The analysis reveals that the dominating deformation mechanism depends critically on the interdimer adhesion, solvent condition, and deformation rate.