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BP: Fachverband Biologische Physik
BP 24: Systems biology
BP 24.3: Vortrag
Mittwoch, 2. April 2014, 10:15–10:30, ZEU 250
Centrosomes are autocatalytic droplets of pericentriolar material organized by centrioles — •David Zwicker1, Markus Decker2, Steffen Jaensch2, Anthony A. Hyman2, and Frank Jülicher1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
During cell division, the mitotic spindle is organized with the help of two centrosomes located at the spindle poles. Centrosomes consist of centrioles that are surrounded by pericentriolar material. The physical nature of centrosomes and in particular of the pericentriolar material remain unclear. We describe centrosomes as liquid-like droplets and study their assembly using a general theoretical description. Our model is based on two forms of the centrosome components: A soluble form in the cytoplasm and a form that tends to phase separate and forms droplets. We show that an autocatalytic chemical transition between these forms can account for the experimentally observed growth dynamics of centrosomes. Such autocatalytic growth requires an initial trigger, which we propose is provides by a catalytic activity of the centrioles. This activity provides a nucleation mechanism that puts centrosome formation under the reliable control by centrioles. Spontaneous homogeneous or heterogeneous nucleation is strongly suppressed in this scenario. Autocatalytic growth can explain rapid centrosome assembly from material provided in the cytoplasm while the control of nucleation by centrioles is reliable. Our theory highlights the role of phase separation in the spatial organization of cells.