title: Actin filaments growing against a barrier with fluctuating shape.
abstract: We study force generation by a set of parallel actin filaments growing against a nonrigid obstacle, in the presence of an external load. The filaments polymerize by either moving the whole obstacle, with a large energy cost, or by causing local distortion in its shape which costs much less energy. The nonrigid obstacle also has local thermal fluctuations due to which its shape can change with time and we describe this using fluctuations in the height profile of a one-dimensional interface with Kardar-Parisi-Zhang dynamics. We find the shape fluctuations of the barrier strongly affect the force generation mechanism. The qualitative nature of the force-velocity curve is crucially determined by the relative time scale of filament and barrier dynamics. The height profile of the barrier also shows interesting variation with the external load. Our analytical calculations within mean-field theory show reasonable agreement with our simulation results.
authors.affiliation: Department of Theoretical Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Sadhu
authors.affiliation: Department of Theoretical Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
authors.forename: Sakuntala
authors.initials: S
authors.lastname: Chatterjee
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology*; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D008954:Models, Biological