Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Molecular Motors
BP 16.6: Vortrag
Mittwoch, 28. März 2012, 16:45–17:00, H 1028
Direct observation of single dyneins diffusing and interacting with microtubules in vivo — •Nenad Pavin1,2, Vaishnavi Ananthanarayanan1, Martin Schattat1, Sven Vogel1, Alexander Krull1, and Iva Tolic-Norrelykke1 — 1Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany — 2Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
Cytoplasmic dynein is a motor protein that exerts force on microtubules and in doing so, drives a myriad of intracellular activities from mitotic spindle positioning to chromosome movements in meiotic prophase. These forces require dynein to be anchored, where the anchoring sites are typically found at the cell cortex. The key question is which mechanism single dyneins use to accumulate at sites where they can generate large collective forces. Here we directly observe single dyneins in fission yeast, which allowed us to identify key steps of the dynein binding process: (i) from the cytoplasm to the microtubule, and (ii) from the microtubule to the cortical anchors. We uncovered that dyneins on the microtubule move, surprisingly, either in a diffusive or a directed manner, where the switch from diffusion to directed movement occurs upon binding of dynein to the cortex. This dual behavior of dynein on the microtubule, together with the two steps of binding, constitute the mechanism how dynein finds cortical anchors in order to generate large-scale movements in the cell.