Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 45: Systems biology
BP 45.1: Talk
Thursday, March 19, 2015, 15:00–15:15, H 1028
Centriole Centering in Centrosomes: Behavior of Catalytic Particles in Active Droplets — •David Zwicker1,2, Anthony A. Hyman3, and Frank Jülicher2 — 1Harvard University, Cambridge MA, USA — 2Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 3Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
Centrosomes are membrane-less organelles, which are important for cell division. A centrosome consist of liquid-like pericentriolar material that accumulates around a centriole pair. We describe the centrosome as an active droplet, where the pericentriolar material is created from soluble building blocks by chemical reactions that are catalyzed both inside the droplet and at the centrioles [D. Zwicker, M. Decker, S. Jaensch, A. A. Hyman, F. Jülicher, PNAS 111 E2636-45 (2014)]. This model accounts for the observed nucleation and growth behavior as well as the suppression of Ostwald ripening.
Here, we analyze this model further and focus on the effects of the material fluxes that are created by the interplay of chemical reactions and diffusion. In particular, we show that centrioles exhibit an effective centering force if their catalytic activity is large enough. Furthermore, fluctuations of the spherical droplet shape are suppressed, even for an arbitrarily small surface tension. The non-equilibrium conditions created by the chemical reactions thus allow to control important properties of active droplets.