Seminar “Nonequilibrium dynamics and fluctuations in the cytoskeleton”

Date

Thursday, 23th of May of 2019

Time

10:00 am – 11:00 am

Place

University of Barcelona
Faculty of Physics Building
Room 3.20, 3rd floor 

Speaker

Dr Fred MacKintosh, Rice University (USA)

Abstract

Much like the bones in our bodies, the cytoskeleton consisting of filamentous proteins largely determines the mechanical response and stability of cells. Unlike passive materials, however, living cells are kept far out of equilibrium by metabolic processes and energy-consuming molecular motors that generate forces to drive the machinery behind various cellular processes.

We describe recent advances both in theoretical modeling of such active gels, as well as experiments on reconstituted in vitro acto-myosin networks and living cells. We show how such internal force generation by motors can lead to dramatic mechanical effects, including strong mechanical stiffening.

Furthermore, stochastic motor activity can lead to non-equilibrium diffusive-like motion in cells. As a result of enzymatic activity at the molecular scale, living systems characteristically violate detailed balance, a fundamental principle of equilibrium statistical mechanics. We discuss fundamental non-equilibrium signatures of living systems, including violations of detailed balance at the meso-scale of whole cells.