Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 58: Cytoskeletal Filaments
BP 58.4: Vortrag
Donnerstag, 10. März 2016, 10:30–10:45, H44
Microtubule bundle formation is driven by angular diffusion of microtubules and forces exerted by cross-linkers — •Marcel Prelogović1, Lora Winters2, Ana Milas3, Iva Tolić3, and Nenad Pavin1 — 1Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia — 2Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany — 3Division of Molecular Biology, Ruder Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
During mitosis, microtubules (MTs) form a spindle, which is responsible for proper segregation of the genetic material. Most of the spindle MTs are organized into bundles by cross-linking proteins. A key question is what are the physical principles underlying the formation and stability of MT bundles. Here we show (Prelogović et.al., submitted), by introducing a model and experimentally testing its predictions, that random angular movement of MTs around the spindle pole and forces exerted by passive cross-linking proteins are sufficient for the formation of stable MT bundles. Our model predicts that the time needed for bundle formation depends mainly on the concentration of cross-linking proteins and the angular diffusion of the MT, but weakly on MT length. We confirmed these predictions by experiments in wild-type and ase1Δ fission yeast cells. In conclusion, the angular motion drives the alignment of MTs, which in turn allows the cross-linking proteins to connect the MTs into a stable bundle.