Force Amplification Response of Actin Filaments under Confined Compression

Buckling of semiflexible filaments under compression

A model for filament buckling at finite temperatures is presented. Starting from the classical worm-like chain model under constant compression, we use a mean-field approach for filament inextensibility to find the complete partition function. We find that there is a simple interpolation formula that describes the free energy of chains or filaments as a function of end-to-end separation, which ...

Effects of Hydrolysis on Force Generation by Actin Filaments

The effects of ATP hydrolysis on actin polymerization-based force generation are calculated using a multistate two-state Brownian-ratchet model based on measured polymerization curves. For ensembles of filaments pushing against a rigid obstacle, the stall force per filament can be much less than the equilibrium ATP-actin stall force. PACS numbers: 87.15.Rn,87.17.Jj,87.16.Ac,87.15.Cc

Force-Velocity Measurements of a Few Growing Actin Filaments

The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filame...

Actin Filaments

Buckling of viscous filaments of a fluid under compression stresses.

We study the compression of viscous filaments at constant velocity. If slender enough, the filament bends, a viscous analogue of Euler elastic buckling. We measure the characteristic time of this viscous buckling and discuss the link with the elastic critical compression. We show that the analogy only holds in the limit of large capillary numbers. Otherwise capillarity has a stabilizing effect,...