Cell Reports
Volume 21, Issue 10, 5 December 2017, Pages 2696-2705
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Report
Structure and Function of an Actin-Based Filter in the Proximal Axon

https://doi.org/10.1016/j.celrep.2017.11.046Get rights and content
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Highlights

  • Dynamic actin patches are present in the proximal axon of live neurons

  • Patches are present shortly after axonal specification in culture and in vivo

  • Constitutively active plus-end-directed myosins localize to the soma and dendrites

  • ARP2/3 is present in patches and is necessary for localization of dendritic proteins

Summary

The essential organization of microtubules within neurons has been described; however, less is known about how neuronal actin is arranged and the functional implications of its arrangement. Here, we describe, in live cells, an actin-based structure in the proximal axon that selectively prevents some proteins from entering the axon while allowing the passage of others. Concentrated patches of actin in proximal axons are present shortly after axonal specification in rat and zebrafish neurons imaged live, and they mark positions where anterogradely traveling vesicles carrying dendritic proteins halt and reverse. Patches colocalize with the ARP2/3 complex, and when ARP2/3-mediated nucleation is blocked, a dendritic protein mislocalizes to the axon. Patches are highly dynamic, with few persisting longer than 30 min. In neurons in culture and in vivo, actin appears to form a contiguous, semipermeable barrier, despite its apparently sparse distribution, preventing axonal localization of constitutively active myosin Va but not myosin VI.

Cited by (0)

2

Present address: Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA

3

Present address: Department of Neuroscience and Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA

4

These authors contributed equally

5

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