Regular Article

The European Physical Journal E

, Volume 21, Issue 3, pp 209-222

Growth of attached actin filaments

  • J. ZhuAffiliated withDepartment of Physics, Washington University Email author 
  • , A. E. CarlssonAffiliated withDepartment of Physics, Washington University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract.

In several studies of actin-based cellular motility, the barbed ends of actin filaments have been observed to be attached to moving obstacles. Filament growth in the presence of such filament-obstacle interactions is studied via Brownian dynamics simulations of a three-dimensional energy-based model. We find that with a binding energy greater than 24k B T and a highly directional force field, a single actin filament is able to push a small obstacle for over a second at a speed of half of the free filament elongation rate. These results are consistent with experimental observations of plastic beads in cell extracts. Calculations of an external force acting on a single-filament-pushed obstacle show that for typical in vitro free-actin concentrations, a 3pN pulling force maximizes the obstacle speed, while a 4pN pushing force almost stops the obstacle. Extension of the model to treat beads propelled by many filaments suggests that most of the propulsive force could be generated by attached filaments.

PACS.

82.35.Pq Biopolymers, biopolymerization 87.15.Aa Theory and modeling; computer simulation 87.15.Rn Reactions and kinetics; polymerization