TY - JOUR
T1 - Feedback-Driven Assembly of the Axon Initial Segment
AU - Fréal, Amélie
AU - Rai, Dipti
AU - Tas, Roderick P
AU - Pan, Xingxiu
AU - Katrukha, Eugene A
AU - van de Willige, Dieudonnée
AU - Stucchi, Riccardo
AU - Aher, Amol
AU - Yang, Chao
AU - Altelaar, A F Maarten
AU - Vocking, Karin
AU - Post, Jan Andries
AU - Harterink, Martin
AU - Kapitein, Lukas C
AU - Akhmanova, Anna
AU - Hoogenraad, Casper C
N1 - Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.
PY - 2019
Y1 - 2019
N2 - 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.
AB - 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.
U2 - 10.1016/j.neuron.2019.07.029
DO - 10.1016/j.neuron.2019.07.029
M3 - Article
C2 - 31474508
SN - 0896-6273
VL - 104
SP - 305-321.e8
JO - Neuron
JF - Neuron
IS - 2
ER -