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BP: Fachverband Biologische Physik

BP 42: Cytoskeletal filaments (joint BP/CPP)

BP 42.4: Vortrag

Donnerstag, 19. März 2015, 10:30–10:45, H 1028

The Dynamics of cross-linked Microtubules in Neurons — •Maximilian Jakobs — University of Cambridge — Universität zu Köln

Microtubule bundles play a central role in the initiation and growth of cellular processes such as neuronal axons and dendrites. However, a quantitative understanding of the involved mechanisms is still lacking. Here, we developed computer simulations that mimic the 1D dynamics of microtubule bundles, cross-linked by ensembles of molecular motors, to investigate the mechanics of growth. We demonstrated that unipolar motors (such as cytoplasmic dynein and most kinesins) are much more effective in initiating axon growth than bipolar motors (such as kinesin 5). The latter, however, are in turn more efficient in filament sorting. We furthermore investigated axon growth dynamics as a function of the restoring forces acting on MT bundles. Our calculations demonstrated that the maximum force such bundles may exert increases monotonically with the elastic rigidity of the opposing membrane, and that it is insensitive to the polarity of filaments in the bundle. Finally, we found that the motor density must exceed a percolation threshold, which depends on the number of filaments in the bundle, before any force can be exerted. Future experiments and considerations might reveal an important contribution of microtubule-generated forces to neuronal symmetry breaking.