Actin filaments growing against a barrier with fluctuating shape

• Published in: arXiv.org
• Main Authors: Sadhu, Raj Kumar, Chatterjee, Sakuntala
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 24.06.2016
• Subjects: Energy costs; Filaments; Mean field theory; Physics - Biological Physics; Physics - Statistical Mechanics; Quantitative Biology - Subcellular Processes; Variation
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1606.07553

We study force generation by a set of parallel actin filaments growing against a non-rigid obstacle, in 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 non-rigid 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 affects 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 calculation within mean-field theory shows reasonable agreement with our simulation results.