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BP: Fachverband Biologische Physik
BP 10: Posters: Molecular Motors
BP 10.1: Poster
Tuesday, April 1, 2014, 09:30–12:30, P1
The role of kinesin-8 in chromosome movements on the mitotic spindle — •Anna H. Klemm1, Nenad Pavin2, and Iva M. Tolic-Norrelykke1 — 1Max Planck Institute CBG, Germany — 2Department of Physics, University of Zagreb, Croatia
During cell division, replicated chromosomes move back and forth around the spindle midzone before they are segregated evenly on the two daughter cells. In a screen in the fission yeast Schizosaccharomyces pombe we studied the role of all known fission yeast kinesin-motors, dynein heavy chain and the microtubule (MT) crosslinking protein ase1 on these movements. We found that the movement was only changed by deletion of the kinesin-8 motor klp5/6, but not by deletion of the other motors. It is known that the motor protein kinesin-8 influences chromosome movements by regulating MT catastrophe. However, the mechanics of how the cell coordinates the movement is unknown. Here we saw that in cells lacking klp5/6 replicated centromeres move over the entire spindle length and switch less often the direction of motion, whereas in wild-type cells, the replicated centromere covers only the central third of the spindle. The centromeres spend a significantly longer time in proximity of the spindle pole body in klp5/6-deleted cells in comparison with wild-type cells. Also, comparable to interphase MT and in vitro studies, klp5-GFP accumulates at the plus-end of polar spindle MTs as they grow and then disappears when the polar spindle MT undergoes catastrophe. We conclude that klp5/6 causes centromere movements away from the spindle pole bodies, most likely by increasing microtubule catastrophe in a length-dependent manner.