Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Transport Processes and Cellular Trafficking
BP 22.2: Vortrag
Donnerstag, 26. März 2009, 14:45–15:00, ZEU 260
Time-resolved analysis of active and passive transport in living cells — •Doris Heinrich1, Delphine Arcizet1, Börn Meier1, Erich Sackmann2, and Joachim Rädler1 — 1Biophysics of Cell Dynamics Group at the Chair of Soft Condensed Matter and Biophysics, Fakultät für Physik und Center for NanoScience (CeNS), Ludwig-Maximilians Universitaet, D-80539 Muenchen, Germany — 2Physik Department E22, Technische Universitaet Muenchen, D-85748 Garching, Germany
The cellular cytoskeleton is a fascinating active network with exceptional dynamic properties due to the presence of ATP-driven motion. In particular, intracellular transport of cargos is effectively mediated by successive phases of diffusion and active cargo movement along microtubule filaments. We investigated the active and passive intracellular transport phenomena by tracking tracer particles in Dictyostelium discoideum cells and analysing the traces with a novel time-resolved mean-square displacement algorithm [1]. By reliably separating both motion types in a statistical analysis, we were able to determine active velocity distributions as well as diffusion coefficient distributions. The exponential decay of active lifetimes reveals a characteristic life time of cargos on microtubules of t=0.65 s. Further, the active velocity distributions exhibit several peaks, revealing the signature of a finite number of molecular motors working collectively.
[1] D. Arcizet, B. Meier, E. Sackmann, J. Raedler and D. Heinrich. Temporal Analysis of Active and Passive Transport in Living Cells, Phys. Rev. Lett., in press