Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Molecular Machines
BP 22.3: Vortrag
Donnerstag, 29. März 2007, 10:15–10:30, H43
Microtubule crosslinking triggers the directional motility of Kinesin-5 — Lukas C. Kapitein1, Benjamin H. Kwok2, Tarun M. Kapoor2, Erwin J.G. Peterman1, and •Christoph F. Schmidt1,3 — 1Department of Physics and Astronomy and Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands — 2Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10021, USA — 3III. Physikalisches Institut, Fakultät für Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Tetrameric kinesin-5 motor proteins are needed for eukaryotic cell division. Assembly and maintenance of the spindle is a highly controlled process. Some kinesins have been found to be cargo-activated, but for a tetrameric motor such was Eg5 it is not obvious how a corresponding mechanism could function. Here we examine factors that influence the switching of Eg5 between the a directional and a diffusive mode, varying buffers and microtubule-binding geometries. We found that at moderate ionic strength, Eg5 moves directionally. In contrast, at higher ionic strength Eg5 diffuses along microtubules without directional bias. Remarkably, under these conditions Eg5 still moves directionally when bound between two microtubules. In the spindle, this functional specialization might allow Eg5 to diffuse on single microtubules without hydrolyzing ATP until the motor gets activated by binding another microtubule.