Physics of Actin Filaments

Friction between actin filaments in a bundle

Macroscopic deformations of filamentous bundles are accompanied by local sliding and stretching of the constituent filaments. Yet the nature of the sliding friction between two aligned filaments interacting through multiple contacts remains largely unexplored. We directly measure the forces between two bundled F-actin filaments.

Read more in A. Ward et. al. Nature Materials 14 (2015)

Bundling Actin filaments with laser Tweezers

Actin Rings and Their Supercoiling Transition

When confined to 2D surface, actin rings will spontaneously anneal end-to-end  and form ring like structures. Furthermore rings labeled with rhodamine phalloidin will spontaneously supercoil, a process that can be directly visualize with video microscopy.

This phenomena has been described by Sanchez et. al. PRL 104 (2010) 098103.

Supercoiling of actin rings

Actin Racquets

In the presence of attractive interactions semi-flexible actin filaments collapse into ring or racquet like structures. Analysis of the resulting racquets yields a new method of measuring the strength of the attractive potential between a pair of filaments.

This work has been described by Lau et al. EPL 87 (2009) 48006.


Actin filament racquets

Bending Rigidity of Actin

Fluctuations of a semi-flexible actin filament confined to a quasi 2D chamber. The methods developed to extract the bending rigidity are described by Brangwyne et al. Biophys. J. 93 (2007),  346-359.