Macro- and microrheology of Intermediate Filaments

The cellular cytoskeleton consists of three types of filaments: microtubules, actin filaments, and intermediate filaments (IFs). In contrast to actin and tubulin, that can be stretched only up to 50% of strain, individual IFs can resist deformations even up to 300% of strain. This surprisingly high extensibility of IFs is caused by their complex internal architecture,which allows for axial sliding of subunits. This makes those filaments more flexible than other cytoskeletal filaments, even though their diameter is comparable to the diameter of actin filaments.
IFs, like other biopolymers, create networks that strain-stiffen. It is unclear, however, whether the origin of the network elasticity  is entropic or enthalpic. To answer this question, we study the viscoelastic properties of networks of IFs (vimentin and GFAP) in the linear and non-linear regime were measured using video tracking microrheology and standard bulk rheometry.

More information: Izabela Piechocka

Collaborators:
Prof. Harald Herrmann, DKFZ Heidelberg
Dr. Elly M. Hol, Oscar Stassen, Martina Mouton, NIN Amsterdam

Confocal microscopy image of a 2 mg/ml fluorescent vimentin network.
Confocal microscopy image of a 2 mg/ml fluorescent vimentin network.
Microrheolgy data of tracers embedded in a vimentin network.
Microrheolgy data of tracers embedded in a vimentin network.
Strain-stiffening of different concentrated vimentin networks under applied shear measured by rheometry.
Strain-stiffening of different concentrated vimentin networks under applied shear measured by rheometry.