Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 22: Posters: Cytoskeletal filaments
BP 22.1: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster A
Novel class of microtubules regulates the forces present in the mitotic spindle — •Maja Novak1, Janko Kajtez2, Anastasia Solomatina2, Matko Glunčić1, Iva M. Tolić2,3, and Nenad Pavin1 — 1Department of Physics, Faculty of Science, University of Zagreb, Croatia (Hrvatska) — 2Max Planck Institute of Molecular Cell Biology and Genetics, Germany — 3Division of Molecular Biology, Rudjer Bošković Institute, Zagreb, Croatia (Hrvatska)
During cell division, the cell forms a spindle in which k-fibers, microtubules that connect chromosomes with the spindle poles, exert forces on the chromosomes via protein complexes termed kinetochores. However, the forces acting on k-fibers and kinetochores are not known. We introduce a simple model in which pairwise k-fibers are described as elastic slender rods, with their tips being connected in a freely joint manner. Model includes a novel class of microtubules, termed bridging microtubules, that extend between the opposite spindle poles and laterally connect k-fibers. This is consistent with our experimental finding in which microtubules between kinetochores have been observed. Our model predicts, for the biologically relevant region of parameters, that the forces acting on k-fibers are compressive despite of the fact that kinetochores are under the tension, which we confirmed by our experiments. The model also predicts that kinetochores are typically located outwards with respect to the bridging microtubules, as we confirmed experimentally, thereby showing the role of the novel class of microtubules in the mitotic spindle.