Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 8: Cell Motility: Neuronal Growth

AKB 8.2: Vortrag

Dienstag, 28. März 2006, 10:30–10:45, ZEU 260

Filopodia orientation determines neurite turning — •Allen Ehrlicher, Timo Betz, Michael Gögler, Daniel Koch, Björn Stuhrmann, and Josef Käs — University of Leipzig, Linnéstr. 5 Abt PWM 04103 Leipzig Germany

Neurons must migrate through a complex array of tissues, chemical signals, and mechanical stimuli to form the connections necessary for life. At the leading edge of neuronal extensions are highly dynamic structures called growth cones, which navigate through the body, interpreting the myriad of signals into appropriate attractive or repulsive responses. Extending beyond the growth cone are spike-like bundles of actin known as filopodia, which communicate many of these environmental cues to the cell, and probe the immediate area of the cell for the best path. We have observed that the orientation of these filopodia strongly predicts growth cone turn behavior. Furthermore, using optical tweezers we directly manipulate the position and orientation of filopodia, and thus are able to induce growth cone turning. All of a cell’s movements are generated by its polymeric cytoskeleton, which is composed principally by actin, microtubules, and motor proteins such as myosin, though the relevance of each constituent is yet unclear. Our observations strengthen the hypothesis that microtubule extension into the growth cone’s peripheral region along filopodia is the dominating factor for neurite turning, and not asymmetry in the polymerizing actin meshwork.