Feedback-Driven Assembly of the Axon Initial Segment

Amélie Fréal, Dipti Rai, Roderick P Tas, Xingxiu Pan, Eugene A Katrukha, Dieudonnée van de Willige, Riccardo Stucchi, Amol Aher, Chao Yang, A F Maarten Altelaar, Karin Vocking, Jan Andries Post, Martin Harterink, Lukas C Kapitein, Anna Akhmanova*, Casper C Hoogenraad*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

28 Citations (Web of Science)

Abstract

The axon initial segment (AIS) is a unique neuronal compartment that plays a crucial role in the generation of action potential and neuronal polarity. The assembly of the AIS requires membrane, scaffolding, and cytoskeletal proteins, including Ankyrin-G and TRIM46. How these components cooperate in AIS formation is currently poorly understood. Here, we show that Ankyrin-G acts as a scaffold interacting with End-Binding (EB) proteins and membrane proteins such as Neurofascin-186 to recruit TRIM46-positive microtubules to the plasma membrane. Using in vitro reconstitution and cellular assays, we demonstrate that TRIM46 forms parallel microtubule bundles and stabilizes them by acting as a rescue factor. TRIM46-labeled microtubules drive retrograde transport of Neurofascin-186 to the proximal axon, where Ankyrin-G prevents its endocytosis, resulting in stable accumulation of Neurofascin-186 at the AIS. Neurofascin-186 enrichment in turn reinforces membrane anchoring of Ankyrin-G and subsequent recruitment of TRIM46-decorated microtubules. Our study reveals feedback-based mechanisms driving AIS assembly.

Original languageEnglish
Pages (from-to)305-321.e8
Number of pages25
JournalNeuron
Volume104
Issue number2
DOIs
Publication statusPublished - 23 Oct 2019
Externally publishedYes

Keywords

  • Animals
  • Ankyrins/metabolism
  • Axon Initial Segment/metabolism
  • Axonal Transport
  • COS Cells
  • Cell Adhesion Molecules/metabolism
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Cytoskeleton
  • Endocytosis
  • Feedback, Physiological
  • HEK293 Cells
  • Hippocampus/cytology
  • Humans
  • Microtubule-Associated Proteins/metabolism
  • Microtubules/metabolism
  • Nerve Growth Factors/metabolism
  • Neurons/metabolism
  • Rats
  • Tripartite Motif Proteins/metabolism
  • GIANT ANKYRIN-G
  • CARGO TRANSPORT
  • ACTIVITY-DEPENDENT RELOCATION
  • LOCALIZATION
  • MICROTUBULES
  • NEUROFASCIN
  • MOTIF
  • MAINTENANCE
  • NEURONAL POLARITY
  • END-BINDING-PROTEIN

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