Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 42: Cytoskeletal filaments (joint BP/CPP)
BP 42.1: Hauptvortrag
Donnerstag, 19. März 2015, 09:30–10:00, H 1028
Microtubules adapt to mechanical stress through spontaneous intra-lattice repair — Laura Schaedel1, Karin John1, Jeremie Gaillard1, Maxence Nachury2, Laurent Blanchoin1, and •Manuel Thery1,3 — 1UMR5168, CEA/CNRS/INRA/Université Grenoble-Alpes, Grenoble, France — 2Stanford University School of Medicine, CA 94305, USA. — 3Hôpital Saint Louis, UMRS1160, INSERM/AP-HP/Université Paris Diderot, Paris, France
Microtubule arrays define the shape of axons, cilia and flagella, and provide tracks for intracellular transport. Although microtubules assembled in vitro are stiffer than other cytoskeletal polymers by several orders of magnitude, intracellular forces lead to the formation of highly bent microtubules. It is currently not known how microtubules tolerate the vast forces exerted on them. It is likely that physical constraints affect microtubule structure and stiffness. Using a newly developed microfluidic device, we find that microtubule stiffness decreases incrementally with each cycle of bending and release. Similar to other cases of material fatigue, rather than a homogenous distribution of stress, the concentration of mechanical stresses turns pre-existing defects in the microtubule lattice into larger damages. Strikingly, damaged microtubules are able to recover their initial stiffness by spontaneously incorporating tubulin into their lattice. These findings demonstrate that microtubules are ductile materials with self-healing properties. Microtubule dynamics is thus not exclusive to the ends and intra-lattice incorporation of tubulin enables spontaneous adaptation to mechanical stresses.