Condensation of actin filaments pushing against a barrier

Abstract

We develop a model to describe the force generated by the polymerization of an array of parallel biofilaments. The filaments are assumed to be coupled only through mechanical contact with a movable barrier. We calculate the filament density distribution and the force-velocity relation with a mean-field approach combined with simulations. We identify two regimes: a non-condensed regime at low force in which filaments are spread out spatially, and a condensed regime at high force in which filaments accumulate near the barrier. We confirm a result previously known from other related studies, namely that the stall force is equal to N times the stall force of a single filament. In the model studied here, the approach to stalling is very slow, and the velocity is practically zero at forces significantly lower than the stall force.

21 pages, 6 figures: Combined figures, fixed typos, added extra material, altered symbolism to avoid confusion. Accepted by New Journal of Physics

References in corpus (4)

• Dynamics of Microtubule Growth and Catastrophe
• Stall force of polymerizing microtubules and filament bundles
• Zipping mechanism for force-generation by growing filament bundles
• Coupling of actin hydrolysis and polymerization: Reduced description with two nucleotide states

Cited by in corpus (15)

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• Actin filaments growing against an elastic membrane: Effect of membrane tension
• Actin filaments growing against a barrier with fluctuating shape
• Compressive force generation by a bundle of living biofilaments
• Solvable model of a many-filament Brownian ratchet
• A semi-flexible model prediction for the polymerization force exerted by a living F-actin filament on a fixed wall
• On the force--velocity relationship of a bundle of rigid living filaments
• Interplay between surface and bending energy helps membrane protrusion formation
• On the pressure exerted by a bundle of independent living filaments
• Filament flexibility enhances power transduction of F-actin bundles
• On the Properties of a Bundle of Flexible Actin Filaments in an Optical Trap
• Actin filaments pushing against a barrier: Comparison between two force generation mechanisms