Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity

The axon initial segment (AIS) is a specialized structure in neurons that resides in between axonal and somatodendritic domains. The localization of the AIS in neurons is ideal for its two major functions: it serves as the site of action potential firing and helps to maintain neuron polarity. It has...

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Main Authors: Steven L. Jones, Tatyana M. Svitkina
Format: Article
Language:English
Published: Wiley 2016-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2016/6808293
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author Steven L. Jones
Tatyana M. Svitkina
author_facet Steven L. Jones
Tatyana M. Svitkina
author_sort Steven L. Jones
collection DOAJ
description The axon initial segment (AIS) is a specialized structure in neurons that resides in between axonal and somatodendritic domains. The localization of the AIS in neurons is ideal for its two major functions: it serves as the site of action potential firing and helps to maintain neuron polarity. It has become increasingly clear that the AIS cytoskeleton is fundamental to AIS functions. In this review, we discuss current understanding of the AIS cytoskeleton with particular interest in its unique architecture and role in maintenance of neuron polarity. The AIS cytoskeleton is divided into two parts, submembrane and cytoplasmic, based on localization, function, and molecular composition. Recent studies using electron and subdiffraction fluorescence microscopy indicate that submembrane cytoskeletal components (ankyrin G, βIV-spectrin, and actin filaments) form a sophisticated network in the AIS that is conceptually similar to the polygonal/triangular network of erythrocytes, with some important differences. Components of the AIS cytoplasmic cytoskeleton (microtubules, actin filaments, and neurofilaments) reside deeper within the AIS shaft and display structural features distinct from other neuronal domains. We discuss how the AIS submembrane and cytoplasmic cytoskeletons contribute to different aspects of AIS polarity function and highlight recent advances in understanding their AIS cytoskeletal assembly and stability.
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spelling doaj-art-e5181c02da9145ffa96ddf4b6bf0f65c2025-08-20T02:21:18ZengWileyNeural Plasticity2090-59041687-54432016-01-01201610.1155/2016/68082936808293Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron PolaritySteven L. Jones0Tatyana M. Svitkina1Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Biology, University of Pennsylvania, Philadelphia, PA 19104, USAThe axon initial segment (AIS) is a specialized structure in neurons that resides in between axonal and somatodendritic domains. The localization of the AIS in neurons is ideal for its two major functions: it serves as the site of action potential firing and helps to maintain neuron polarity. It has become increasingly clear that the AIS cytoskeleton is fundamental to AIS functions. In this review, we discuss current understanding of the AIS cytoskeleton with particular interest in its unique architecture and role in maintenance of neuron polarity. The AIS cytoskeleton is divided into two parts, submembrane and cytoplasmic, based on localization, function, and molecular composition. Recent studies using electron and subdiffraction fluorescence microscopy indicate that submembrane cytoskeletal components (ankyrin G, βIV-spectrin, and actin filaments) form a sophisticated network in the AIS that is conceptually similar to the polygonal/triangular network of erythrocytes, with some important differences. Components of the AIS cytoplasmic cytoskeleton (microtubules, actin filaments, and neurofilaments) reside deeper within the AIS shaft and display structural features distinct from other neuronal domains. We discuss how the AIS submembrane and cytoplasmic cytoskeletons contribute to different aspects of AIS polarity function and highlight recent advances in understanding their AIS cytoskeletal assembly and stability.http://dx.doi.org/10.1155/2016/6808293
spellingShingle Steven L. Jones
Tatyana M. Svitkina
Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
Neural Plasticity
title Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
title_full Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
title_fullStr Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
title_full_unstemmed Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
title_short Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity
title_sort axon initial segment cytoskeleton architecture development and role in neuron polarity
url http://dx.doi.org/10.1155/2016/6808293
work_keys_str_mv AT stevenljones axoninitialsegmentcytoskeletonarchitecturedevelopmentandroleinneuronpolarity
AT tatyanamsvitkina axoninitialsegmentcytoskeletonarchitecturedevelopmentandroleinneuronpolarity