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BP: Fachverband Biologische Physik
BP 6: Cytoskeletal Filaments I
BP 6.3: Talk
Monday, March 12, 2018, 15:30–15:45, H 1058
Metaphase kinetochore movements are regulated by kinesin-8 motors and microtubule dynamic instability — •Agneza Bosilj1, Anna Klemm2, Iva Tolic2,3, and Nenad Pavin1 — 1Department of Physics, Faculty of Science, University of Zagreb, Bijenicka cesta 32, 10000 Zagreb, Croatia — 2Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany — 3Division of Molecular Biology, Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb, Croatia
During metaphase, sister chromatids are connected to microtubules (MTs) extending from the opposite spindle poles via kinetochores, protein complexes on the chromosome. Kinetochores congress to the equatorial plane of the spindle and oscillate around it, with kinesin-8 motors restricting these movements. Yet, the physical mechanism underlying kinetochore movements is unclear. We show that kinetochore movements in the fission yeast Schizosaccharomyces pombe are regulated by kinesin-8-promoted MT catastrophe, force-induced rescue and MT dynamic instability. A candidate screen showed that only kinesin-8 motors Klp5/Klp6 are required for kinetochore centering. Our theoretical model with Langevin description of MT dynamic instability shows that kinesin-8 motors are required for kinetochore centering, whereas sensitivity of rescue to force is necessary for the generation of oscillations. We found that irregular kinetochore movements occur for a broader range of parameters than regular oscillations. Thus, our work shows how regulation of MT dynamic instability contributes to kinetochore congression and the accompanying oscillations.