When neurons migrate, there is a leading process in the front of the cell body and a trailing process. The leading process contains actin filaments that enable the cell body of the neuron to move forward. A recent paper describes how the microtubule-based motor kinesin-6 plays an important role in neuronal migration. Kinesin-6 is best known for its role in cytokinesis, the physical division of a cell after mitosis. Falnikar and colleagues found that kinesin-6 concentrates in the same region as actin filaments in the leading process of a migrating neuron. Without kinesin-6, neurons lose their bipolar leading-trailing process morphology, concentrate actin filaments in more than one process, and either remain stationary or continually change the direction of migration. In addition, Falnikar and colleagues found that kinesin-6 signals through the GTPase activating protein MgcRacGAP to regulate the actin cytoskeleton, as it does during cytokinesis. In the images above, control neurons (top time-lapse series) moved in a single direction, while neurons depleted of kinesin-6 bottom) frequently changed directions.
BONUS!! Check out a movie of a wandering, migrating kinesin-6-depleted neuron below.
Aditi Falnikar, Shubha Tole, Mei Liu, Judy S. Liu, & Peter W. Baas (2013). Polarity in Migrating Neurons Is Related to a Mechanism Analogous to Cytokinesis Current Biology, 23 (13), 1215-1220 DOI: 10.1016/j.cub.2013.05.027 Copyright ©2013 Elsevier Ltd. All rights reserved.