Neuronal cell morphogenesis depends on the proper regulation of microtubule-based transport, but the underlying mechanisms are not well understood. Here, we report our study of MAP7, a unique microtubule-associated protein that interacts with both microtubules and the motor protein kinesin-1. Structure-function analysis in rat embryonic sensory neurons shows that the kinesin-1 interacting domain in MAP7 is required for axon and branch growth but not for branch formation. Also, two unique microtubule binding sites are found in MAP7 that have distinct dissociation kinetics and are both required for branch formation. Furthermore, MAP7 recruits kinesin-1 dynamically to microtubules, leading to alterations in organelle transport behaviors, particularly pause/speed switching frequency. As MAP7 is localized to branch sites, our results suggest a novel mechanism mediated by the dual interactions between MAP7 with microtubules and kinesin-1 in the precise control of microtubule-based transport during axon morphogenesis.
- Le Ma
- Le Ma
- Kristen J Verhey
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: The study was performed in strict accordance with the Guidelines for the Care and Use of Laboratory Animals of the National Institutes of Health and the approved IACUC protocol (#01560) of the Thomas Jefferson University.
- Kang Shen, Stanford University, United States
© 2018, Tymanskyj et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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