Microtubule retrograde flow retains neuronal polarization in a fluctuating state
1 German Center for Neurodegenerative Diseases, Bonn
In developing neurons, a neurite is formed by more than a hundred microtubules. This microtubule network has been thought to act as stationary tracks, in which only individual microtubules could be transported. Using live cell imaging of microtubule patches in neurons, we found that instead the whole microtubule network flows retrogradely into the soma. This microtubule retrograde flow enables neurons to probe various locations with their neurites in a random, fluctuating manner before developing the axon, the long-sought mechanism to singling one neurite out to become the axon. Thus, microtubule retrograde flow provides neurons with the initial plasticity of their polarization program to direct their morphogenetic transformation.