Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 75: Active Matter (joint session BP/CPP/DY)

DY 75.9: Vortrag

Freitag, 16. März 2018, 11:30–11:45, H 1058

Hydrodynamic theory of aster positioning by motor proteins — •Andrej Vilfan — J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia

In fertilized egg cells of certain species the male pronucleus is transported to the center of the cell by growing an asymmetric microtubule aster, which then serves as a track for motor proteins carrying vesicles towards the center. Because these vesicles experience a viscous drag in the surrounding cytoplasm, the motors exert the opposite force on the microtubules. The asymmetry of the aster then leads to a net pulling force towards the cell center. Yet hydrodynamic interactions make the understanding of the process difficult.

Here we discuss a coarse-grained approach where we describe the aster as a porous medium and the moving vesicles as sources of an active pressure gradient. In parallel, we use computational models to determine the parameters of the continuum model. For realistic parameters, we show that a significant proportion (10-20%) of the motor force is converted to a pressure gradient and contributes to aster centering. We conclude that vesicle transport in a viscous environment is a surprisingly efficient way of force generation.