Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Molecular Motors
BP 16.8: Vortrag
Mittwoch, 28. März 2012, 17:15–17:30, H 1028
Microtubules search for lost kinetochores by pivoting around the spindle pole — •Damien Ramunno-Johnson1, Iana Kalinina1, Amitabha Nandi2, Alexander Krull1, Benjamin Lindner2, Nenad Pavin1,3, and Iva Tolic-Norrelykke1 — 1MPI-CBG, Dresden, Germany — 2MPI-PKS, Dresden, Germany — 3University of Zagreb, Zagreb, Croatia
For a mother cell to divide its genetic material equally between the two daughter cells, the chromosomes have to attach to microtubules, which will pull them apart. The linkers between chromosomes and microtubules are kinetochores, protein complexes on the chromosome. The pioneering idea explaining how microtubules find kinetochores, termed "search-and-capture," states that microtubules grow radially from a centrosome in all directions and shrink back, thereby exploring the intracellular space and by chance hitting and capturing the kinetochores. In fission yeast, kinetochore capture by microtubules can be observed when kinetochores are lost in the nucleoplasm, which can be induced by spindle disassembly during metaphase. It is, however, unknown how microtubules find lost kinetochores. We observed that lost kinetochores are captured by microtubules pivoting around the spindle pole body, instead of extending towards the kinetochores. By introducing a theoretical model, we show that the observed random movement of microtubules is sufficient to explain the process of kinetochore capture. We thus reveal a mechanism where microtubules explore space by pivoting, as they search for intracellular targets.