Zhu Xiaowei, Yu Yanyan, Jiang Zhuqian, Otani Yoshinori, Fujitani Masashi
Department of Anatomy and Neuroscience, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-shi 693-8501, Shimane, Japan.
Biomolecules. 2025 Jun 19;15(6):901. doi: 10.3390/biom15060901.
The axon initial segment (AIS) is a specialized subcellular domain that plays an essential role in action potential initiation and the diffusion barrier. A key organizer of the AIS is Ankyrin-G, a scaffolding protein responsible for clustering voltage-gated ion channels, cell adhesion molecules (CAMs), and cytoskeletal components at this critical neuronal domain. Recent proteomic analyses have revealed a complex network of proteins in the AIS, emphasizing Ankyrin-G's central role in its molecular architecture. This review discusses new findings in the study of AIS-associated proteins. It explains how Ankyrin-G and its binding partners (such as ion channels, CAMs, spectrins, actin, and microtubule-associated proteins including end-binding protein 3, tripartite motif-containing protein 46, and calmodulin-regulated spectrin-associated protein 2) organize their structure. Understanding the dynamic regulation and molecular interactions within the AIS offers insights into neuronal excitability and reveals potential therapeutic targets for axonal dysfunction-related diseases. Through these dynamic interactions, Ankyrin-G ensures the proper alignment and dense clustering of key channel complexes, thereby maintaining the AIS's distinctive molecular and functional identity. By further unraveling the complexity of Ankyrin-G's interactome, our understanding of AIS formation, maintenance, and plasticity will be considerably enhanced, contributing to the elucidation of the pathogenesis of neurological and neuropsychiatric disorders.
轴突起始段(AIS)是一个特殊的亚细胞结构域,在动作电位起始和扩散屏障中发挥着至关重要的作用。AIS的关键组织者是锚蛋白G,它是一种支架蛋白,负责在这个关键的神经元结构域聚集电压门控离子通道、细胞粘附分子(CAMs)和细胞骨架成分。最近的蛋白质组学分析揭示了AIS中复杂的蛋白质网络,强调了锚蛋白G在其分子结构中的核心作用。这篇综述讨论了AIS相关蛋白研究中的新发现。它解释了锚蛋白G及其结合伙伴(如离子通道、CAMs、血影蛋白、肌动蛋白和微管相关蛋白,包括末端结合蛋白3、含三方基序蛋白46和钙调蛋白调节的血影蛋白相关蛋白2)是如何组织其结构的。了解AIS内的动态调节和分子相互作用有助于深入了解神经元兴奋性,并揭示轴突功能障碍相关疾病的潜在治疗靶点。通过这些动态相互作用,锚蛋白G确保关键通道复合物的正确排列和密集聚集,从而维持AIS独特的分子和功能特性。通过进一步揭示锚蛋白G相互作用组的复杂性,我们对AIS形成、维持和可塑性的理解将得到显著增强,有助于阐明神经和神经精神疾病的发病机制。