Regensburg 2002 – wissenschaftliches Programm

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SYBM: Physik biologischer Materie

SYBM 401: Physics of biological matter: Poster

SYBM 401.43: Poster

Dienstag, 12. März 2002, 18:00–19:30, H37

A quasi-solid drag force arises during enforced actin motion through the entangled actin gel. — •Nikita Ter-Oganessian, Marius Dichtl, Erich Sackmann und Alexei Boulbitch — Dept. fuer Biophysik E22, Technische Universitaet Muenchen, James-Franck-Str. 1, D-85747 Garching bei Muenchen

We report low-frequency magnetic tweezers measurements of viscoelasticity of entangled actin networks with either magnetic beads or beads attached to the tip of a fluorescently labeled actin filament.

We present experimental evidence that the motion of the bead gives rise to pronounced creep of those actin filaments in its close environment, which are relatively straight. In contrast the initially bent filaments experience a deformation rather than a creep.

We further show experimentally that during the enforced filament motion it is trapped by the gel as soon as it is bent.

On the basis of these experiments a theoretical model of the low-frequency friction in the entangled actin gel is proposed. It is based on the concept of an amplification of the filament friction due to its bending.