Article
Neurosciences
Jian Hao Liu, Jeet Bahadur Singh, Margaret Lin Veruki, Espen Hartveit
Summary: AII amacrine cells in mammalian retinas exhibit a unique process resembling an axon initial segment, with the ability to generate action potentials, which may be related to extrasynaptic neurotransmission.
JOURNAL OF COMPARATIVE NEUROLOGY
(2021)
Article
Neurosciences
Israt Jahan, Ryota Adachi, Ryo Egawa, Haruka Nomura, Hiroshi Kuba
Summary: This study reveals that microtubule reorganization via activation of CDK5 plays a role in the plasticity of the axon initial segment (AIS). Treatment with a high-K+ medium shortened the AIS, specifically in neurons tuned to high-frequency sound. CDK5/p35-mediated AIS shortening is achieved by promoting disassembly of microtubules at distal AIS.
JOURNAL OF NEUROSCIENCE
(2023)
Article
Multidisciplinary Sciences
Aurelie Fekete, Norbert Ankri, Romain Brette, Dominique Debanne
Summary: The distal shift of the axon initial segment (AIS) position increases axial resistance and excitability in L-5 pyramidal neurons, resulting in a decrease in the voltage threshold of the somatic action potential.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Cell Biology
Chen Chen, Chien-Hsi Chu, Ying Chu, Ting-Ya Chang, Sheng-Wen Chen, Shu-Yang Liang, Yun-Chi Tsai, Bi-Chang Chen, Hsiung-Lin Tu, Pei-Lin Cheng
Summary: Soft tissue environments play an important role in neuronal morphogenesis. This study reveals that drebrin, a growth cone T-zone protein, modulates growth cone turning in response to brain-derived neurotrophic factor (BDNF) on soft substrates. Structurally, axonal growth cones on soft hydrogels have an expanded T zone with integrated drebrin, F-actin and microtubules. Biochemically, paxillin interacts with drebrin specifically on soft hydrogels. Functionally, BDNF-induced growth cone turning and force generation on soft substrates require phosphorylation of drebrin and association of paxillin with drebrin.
Article
Neurosciences
Anna M. Lipkin, Margaret M. Cunniff, Perry W. E. Spratt, Stefan M. Lemke, Kevin J. Bender
Summary: The study revealed that in mouse layer 5 prefrontal pyramidal neurons, calcium channels were distributed differently, with Ca(V)3 channels leading to high-spot calcium influx in specific regions, while Ca(V)2 channels localized to non-hotspot areas.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Cell Biology
Yuki Ogawa, Matthew N. Rasband
Summary: The study found that the anti-Ranbp2 antibody used previously is not specific for Ranbp2. Experimental results showed that endogenously expressed Ranbp2 is not found at the AIS, but an exogenously expressed N-terminal fragment of Ranbp2 can localize at the AIS and interact with stable microtubules.
JOURNAL OF CELL SCIENCE
(2021)
Article
Neurosciences
Ankang Hu, Rui Zhao, Baihui Ren, Yang Li, Jiangteng Lu, Yilin Tai
Summary: Two types of pyramidal neurons (PyNs) in the prelimbic cortex (PL) of mice, projecting to either the contralateral PL or the ipsilateral basal lateral amygdala, possess distinct axon initial segment (AIS) properties including morphology, ion channel expression, action potential initiation, and axo-axonic synaptic inputs from chandelier cells. The heterogeneity of AISs is more prominent in the superficial layer compared to the deep layer. These findings reveal the cortical layer- and axon projection-specific heterogeneity of PyN AISs, which may contribute to the modulation of spiking properties in different PyN types.
NEUROSCIENCE BULLETIN
(2023)
Review
Cell Biology
Juan Jose Garrido
Summary: Brain channelopathies are neurological disorders caused by genetic mutations that affect ion channels in the brain. These specialized proteins control the electrical activity of nerve cells, and when they do not function properly, they can lead to a range of neurological symptoms. This review focuses on how alterations in the structure, plasticity, and composition of the axon initial segment (AIS) can result in changes in action potentials and neuronal dysfunction, leading to brain diseases.
Article
Neurosciences
Hiromi Tamada, Sumiko Kiryu-Seo, Sohgo Sawada, Hiroshi Kiyama
Summary: This study revealed changes in the extracellular glial environment and intracellular mitochondrial localization in the AIS after axonal injury. Microglial adhesions to the AIS and an increase in mitochondrial abundance within the AIS were observed post-injury. These alterations may play crucial roles in the regeneration of injured neurons following axonal injury.
JOURNAL OF COMPARATIVE NEUROLOGY
(2021)
Article
Neurosciences
Merci N. Best, Yunu Lim, Nina N. Ferenc, Nayoung Kim, Lia Min, Dora Bigler Wang, Kamyar Sharifi, Anna E. Wasserman, Sloane A. McTavish, Karsten H. Siller, Marieke K. Jones, Paul M. Jenkins, James W. Mandell, George S. Bloom
Summary: xcTauOs are sensitive to the AIS structure, which can cause AIS shortening and decrease in TRIM46 concentration. It has been demonstrated through experiments that this damage is dependent on intracellular tau. The observed AIS reduction in AD neurons may also be attributed to the combined effect of xcTauOs and endogenous neuronal tau.
JOURNAL OF ALZHEIMERS DISEASE
(2023)
Review
Neurosciences
Tiago Ferreira da Silva, Luis S. Granadeiro, Diogo Bessa-Neto, Liliana L. Luz, Boris V. Safronov, Pedro Brites
Summary: This study reveals a previously unknown mechanism that links the phospholipid composition of the neuronal membrane to the positional assembly of the AIS. Deficiency of plasmalogens is shown to displace the AIS to more distal positions and reduce excitability, leading to potential implications for neurodegenerative diseases characterized by plasmalogen defects such as Alzheimer's and Parkinson's disease. Rescuing the impaired AKT signaling pathway normalizes AIS position independently of the biochemical defect.
PROGRESS IN NEUROBIOLOGY
(2021)
Article
Neurosciences
Luiza Filipis, Marco Canepari
Summary: **This study presents the first optical measurement of Na+ currents in the axon initial segment (AIS) of pyramidal neurons in the somatosensory cortex, demonstrating the ability to track the kinetics of Na+ current during action potential generation more effectively. The results also show a correlation between the kinetics of Na+ current at different distances from the soma and the somatic action potential. Additionally, comparison with computer simulations of NEURON models revealed the potential of this approach in estimating the native behavior of Na+ channels accurately.
JOURNAL OF PHYSIOLOGY-LONDON
(2021)
Article
Anatomy & Morphology
Yiming Wang, Meiling Guan, Yan Zhang, Karl Zhanghao, Peng Xi
Summary: Glucose triggers the plasticity of axon initial segment (AIS) in cultured neurons. Structured illumination microscopy imaging reveals an increased spacing in the AIS lattice structure under glucose treatment. The 480-kDa AnkG plays a crucial role in AIS plasticity.
MICROSCOPY RESEARCH AND TECHNIQUE
(2022)
Article
Neurosciences
Wei Zhang, Maria Ciorraga, Pablo Mendez, Diana Retana, Norah Boumedine-Guignon, Beatriz Achon, Michael Russier, Dominique Debanne, Juan Jose Garrido
Summary: The axon initial segment (AIS) is crucial for neuronal function, with the actin and microtubule cytoskeleton playing a key role in regulating AIS structure and function, and formins playing a critical role in maintaining AIS composition and stability.
MOLECULAR NEUROBIOLOGY
(2021)
Article
Neurosciences
Xuanyuan Wu, Haixiang Li, Jiechang Huang, Mengqi Xu, Cheng Xiao, Shuijin He
Summary: COUP-TFI is a crucial regulator of AIS diameter in both developing and adult mouse neocortex, influencing changes in AIS diameter and impairment of AP generation. Overexpression of COUP-TFI increases AIS diameter and facilitates AP generation, but weakens the receiving spontaneous network.
NEUROSCIENCE BULLETIN
(2022)
