scholarly journals Requirement of subunit co-assembly and ankyrin-G for M-channel localization at the axon initial segment

2007 ◽  
Vol 120 (6) ◽  
pp. 953-963 ◽  
Author(s):  
H. B. Rasmussen ◽  
C. Frokjaer-Jensen ◽  
C. S. Jensen ◽  
H. S. Jensen ◽  
N. K. Jorgensen ◽  
...  
Keyword(s):  
Initial Segment ◽  
Axon Initial Segment ◽  
Ankyrin G

scholarly journals Ankyrin-G induces nucleoporin Nup358 to associate with the axon initial segment of neurons

2019 ◽  
Vol 132 (18) ◽  
pp. jcs222802 ◽  
Author(s):  
Bouchra Khalaf ◽  
Alessandro Roncador ◽  
Francesca Pischedda ◽  
Antonio Casini ◽  
Sabine Thomas ◽  
...  
Keyword(s):  
Initial Segment ◽  
Axon Initial Segment ◽  
Ankyrin G

scholarly journals Nanoscale architecture of the axon initial segment reveals an organized and robust scaffold

2015 ◽  
Author(s):  
Christophe Leterrier ◽  
Jean Potier ◽  
Ghislaine Caillol ◽  
Claire Debarnot ◽  
Fanny Rueda Boroni ◽  
...  
Keyword(s):  
Action Potentials ◽  
Initial Segment ◽  
Axon Initial Segment ◽  
Molecular Architecture ◽  
Physiological Functions ◽  
Structural Stabilization ◽  
Ankyrin G ◽  
Stochastic Optical Reconstruction Microscopy ◽  
Optical Reconstruction ◽  
Actin Rings

The Axon Initial Segment [AIS], located within the first 30 μm of the axon, has two essential roles in generating action potentials and maintaining axonal identity. AIS assembly depends on a βIV-spectrin / ankyrin G scaffold, but its macromolecular arrangement is not well understood. Here we quantitatively determined the AIS nanoscale architecture using STochastic Optical Reconstruction Microscopy [STORM]. First we directly demonstrate that the 190-nm periodicity of the AIS submembrane lattice results from longitudinal, head-to-head βIV-spectrin molecules connecting actin rings. Using multicolor 3D-STORM, we resolve the nanoscale organization of ankyrin G: its aminoterminus associates with the submembrane lattice, whereas the carboxyterminus radially extends (~32 nm on average) toward the cytosol. This AIS nano-architecture is highly resistant to cytoskeletal perturbations, advocating its role in structural stabilization. Our findings provide a comprehensive view of the AIS molecular architecture, and will help understanding the crucial physiological functions of this compartment.

scholarly journals End-binding proteins EB3 and EB1 link microtubules to ankyrin G in the axon initial segment

2011 ◽  
Vol 108 (21) ◽  
pp. 8826-8831 ◽  
Author(s):  
C. Leterrier ◽  
H. Vacher ◽  
M.-P. Fache ◽  
S. A. d'Ortoli ◽  
F. Castets ◽  
...  
Keyword(s):  
Initial Segment ◽  
Binding Proteins ◽  
Axon Initial Segment ◽  
Ankyrin G

scholarly journals M-current inhibition rapidly induces a unique CK2-dependent plasticity of the axon initial segment

2017 ◽  
Vol 114 (47) ◽  
pp. E10234-E10243 ◽  
Author(s):  
Jonathan Lezmy ◽  
Maya Lipinsky ◽  
Yana Khrapunsky ◽  
Eti Patrich ◽  
Lia Shalom ◽  
...  
Keyword(s):  
Initial Segment ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Primary Cultures ◽  
Axon Initial Segment ◽  
Channel Activity ◽  
Hippocampal Pyramidal Neurons ◽  
M Current ◽  
Ankyrin G ◽  
Trigger Zone

Alterations in synaptic input, persisting for hours to days, elicit homeostatic plastic changes in the axon initial segment (AIS), which is pivotal for spike generation. Here, in hippocampal pyramidal neurons of both primary cultures and slices, we triggered a unique form of AIS plasticity by selectively targeting M-type K+ channels, which predominantly localize to the AIS and are essential for tuning neuronal excitability. While acute M-current inhibition via cholinergic activation or direct channel block made neurons more excitable, minutes to hours of sustained M-current depression resulted in a gradual reduction in intrinsic excitability. Dual soma–axon patch-clamp recordings combined with axonal Na+ imaging and immunocytochemistry revealed that these compensatory alterations were associated with a distal shift of the spike trigger zone and distal relocation of FGF14, Na+, and Kv7 channels but not ankyrin G. The concomitant distal redistribution of FGF14 together with Nav and Kv7 segments along the AIS suggests that these channels relocate as a structural and functional unit. These fast homeostatic changes were independent of l-type Ca2+ channel activity but were contingent on the crucial AIS protein, protein kinase CK2. Using compartmental simulations, we examined the effects of varying the AIS position relative to the soma and found that AIS distal relocation of both Nav and Kv7 channels elicited a decrease in neuronal excitability. Thus, alterations in M-channel activity rapidly trigger unique AIS plasticity to stabilize network excitability.

scholarly journals Cooperative Interactions between 480 kDa Ankyrin-G and EB Proteins Assemble the Axon Initial Segment

2016 ◽  
Vol 36 (16) ◽  
pp. 4421-4433 ◽  
Author(s):  
A. Freal ◽  
C. Fassier ◽  
B. Le Bras ◽  
E. Bullier ◽  
S. De Gois ◽  
...  
Keyword(s):  
Initial Segment ◽  
Axon Initial Segment ◽  
Cooperative Interactions ◽  
Ankyrin G

scholarly journals Ankyrin G membrane partners drive the establishment and maintenance of the axon initial segment

2016 ◽  
Author(s):  
Christophe Leterrier ◽  
Nadine Clerc ◽  
Fanny Rueda-Boroni ◽  
Audrey Montersino ◽  
Bénédicte Dargent ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Adhesion Molecules ◽  
Hippocampal Neurons ◽  
Initial Segment ◽  
Neuronal Development ◽  
Axon Initial Segment ◽  
Membrane Anchor ◽  
Ankyrin G ◽  
Membrane Components ◽  
Cultured Hippocampal Neurons

The axon initial segment (AIS) is a specialized neuronal compartment that plays a key role in neuronal development and excitability. It concentrates multiple ion channels and cell adhesion molecules. The anchoring of these AIS membrane components is known to be highly dependent of the scaffold protein ankyrin G (ankG) but whether ankG membrane partners play a reciprocal role in ankG targeting and stabilization has not been studied yet. In cultured hippocampal neurons and cortical organotypic slices, we found that shRNA-mediated knockdown of ankG membrane partners led to a decrease of ankG concentration and perturbed the AIS formation and maintenance. These perturbations were rescued by expressing an AIS-targeted sodium channel, or a minimal construct containing the ankyrin-binding domain of Nav1.2 and a membrane anchor. We thus demonstrate that a tight and precocious association of ankG to its membrane partners is crucial for the establishment and maintenance of the AIS.

scholarly journals Ankyrin G Membrane Partners Drive the Establishment and Maintenance of the Axon Initial Segment

2017 ◽  
Vol 11 ◽  
Author(s):  
Christophe Leterrier ◽  
Nadine Clerc ◽  
Fanny Rueda-Boroni ◽  
Audrey Montersino ◽  
Bénédicte Dargent ◽  
...  
Keyword(s):  
Initial Segment ◽  
Axon Initial Segment ◽  
Ankyrin G
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