Berlin 2018 – scientific programme

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BP: Fachverband Biologische Physik

BP 23: Bioimaging and Biopspectroscopy II

BP 23.7: Talk

Wednesday, March 14, 2018, 16:45–17:00, H 2013

Non-equilibrium forces drive the anomalous diffusion of vital cell constituents — •Lorenz Stadler, Konstantin Speckner, and Matthias Weiss — Experimentalphysik 1, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth

Diffusion is the basic mode of motion for supra-molecular assemblies in living cells, often with an anomalous scaling of the mean square displacement, with $ text $. Considerable effort has been invested to uncover the underlying types of subdiffusive processes, yet often with the tacit assumption that the involved random forces are mostly of thermal origin. Contrary to this simple assumption, our single-particle tracking data on the subdiffusive motion of telomeres in the nucleus of mammalian cells reveals an important role of cytoskeleton-associated non-equilibrium forces [1]. In line with this finding, we also have found strong non-equilibrium contributions in the trajectories of membrane domains in the cells’ Endoplasmic Reticulum (so-called ’ER exit sites’). Due to the complex topology of the ER, exit sites not only are shaken by the cytoskeleton-driven motion of the entire ER network but they also show an (activated) subordinated motion on individual ER tubules. Altogether, our data show that even subdiffusive motion patterns in cells may not represent simple thermal transport process but rather are non-equilibrium events.

[1] Stadler & Weiss, New J. Phys. (in press) 2017