The ability of neurons to generate multiple arbor terminals from a single axon is crucial for establishing proper neuronal wiring. While growth and retraction of arbor terminals are differentially regulated within the axon, the mechanisms by which neurons locally control their structure remain largely unknown. In the present study, we found that the head domain of kinesin-1 (K5H) preferentially marks a subset of arbor terminals. Time-lapse imaging clarified that these arbor terminals are more stable than others, because of low retraction rate. Local inhibition of kinesin-1 in the arbor terminal by chromophore-assisted light inactivation (CALI) enhanced retraction rate. The microtubule turnover is locally regulated depending on the length from the branching point to the terminal end, but does not directly correlate with K5H. Conversely, F-actin signal values in arbor terminals correlate spatiotemporally with K5H, and inhibition of actin turnover prevented retraction. Results from the present study revealed a novel system mediated by kinesin-1 sorting in axons, which differentially controls stability of arbor terminals.
- Received November 23, 2015.
- Accepted August 2, 2016.
- © 2016. Published by The Company of Biologists Ltd