Non-equilibrium fluctuations of a semi-flexible filament driven by active cross-linkers

¹ Department of Physics, Saarland University - D-66123 Saarbrücken, Germany
² Laboratoire de Physique Théorique, CNRS (UMR 8627), Univ. Paris-Sud, Univ. Paris-Saclay F-91405 Orsay, France
³ Laboratoire de Physique Théorique et Modèles Statistiques, CNRS (UMR 8626), Univ. Paris-Sud, Univ. Paris-Saclay - F-91405 Orsay, France

Received: 25 October 2017
Accepted: 8 January 2018

Abstract

The cytoskeleton is an inhomogeneous network of semi-flexible filaments, which are involved in a wide variety of active biological processes. Although the cytoskeletal filaments can be very stiff and embedded in a dense and cross-linked network, it has been shown that, in cells, they typically exhibit significant bending on all length scales. In this work we propose a model of a semi-flexible filament deformed by different types of cross-linkers for which one can compute and investigate the bending spectrum. Our model allows to couple the evolution of the deformation of the semi-flexible polymer with the stochastic dynamics of linkers which exert transversal forces onto the filament. We observe a dependence of the bending spectrum for some biologically relevant parameters and in a certain range of wave numbers q, as observed in some experiments. However, generically, the spatially localized forcing and the non-thermal dynamics both introduce deviations from the thermal-like spectrum.