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

Ines Weber 1, 2 Cecile Appert-Rolland 2 Gregory Schehr 3 Ludger Santen 1

EPL - Europhysics Letters, European Physical Society/EDP Sciences/Società Italiana di Fisica/IOP Publishing, 2017

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 $q^{-2}$ dependence of the bending spectrum for some biologically relevant parameters and in a certain range of wavenumbers $q$. However, generically, the spatially localized forcing and the non-thermal dynamics both introduce deviations from the thermal-like $q^{-2}$ spectrum.

  • 1. Saarland University [Saarbrücken]
  • 2. LPT - Laboratoire de Physique Théorique d'Orsay [Orsay]
  • 3. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques