Loss of Neurofascin-186 Disrupts Alignment of AnkyrinG Relative to Its Binding Partners in the Axon Initial Segment
Loss of Neurofascin-186 Disrupts Alignment of AnkyrinG Relative to Its Binding Partners in the Axon Initial Segment
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DOI：
10.3389/fncel.2019.00001
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发表时间：
2019-01-22
影响因子：
5.3
通讯作者：
Hoppa, Michael B.
中科院分区：
文献类型：
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作者：
Alpizar, Scott A.;Baker, Arielle L.;Hoppa, Michael B.
轴突起始段（AIS）是轴突近端部分内的一个特殊区域，它启动动作电位在很大程度上要归功于钠通道的富集。支架蛋白锚蛋白 G (AnkG) 对于钠通道以及其他几种细胞内和细胞外蛋白向 AIS 的募集至关重要。在本研究中，我们探讨了细胞粘附分子（CAM）神经成束蛋白-186（NF-186）在排列培养的大鼠海马神经元中 AIS 的各个分子成分中的作用。使用 CRISPR 耗竭策略来消除 NF 表达，我们发现 NF 的缺失选择性地扰乱 AnkG 积累及其在 AIS 内的相对近端分布。我们发现钠通道的过度表达可以恢复 AnkG 的积累，但不能恢复其在不存在 NF 的情况下在 AIS 内的分布改变。我们继续证明，尽管 NF 的丧失改变了 AnkG 分布，但 AIS 内的钠通道功能仍然正常。总而言之，这些结果表明 AIS 内 AnkG 和钠通道积累的调节可以彼此独立发生，可能由其他结合配偶体（例如 NF）介导。
The axon initial segment (AIS) is a specialized region within the proximal portion of the axon that initiates action potentials thanks in large part to an enrichment of sodium channels. The scaffolding protein ankyrinG (AnkG) is essential for the recruitment of sodium channels as well as several other intracellular and extracellular proteins to the AIS. In the present study, we explore the role of the cell adhesion molecule (CAM) neurofascin-186 (NF-186) in arranging the individual molecular components of the AIS in cultured rat hippocampal neurons. Using a CRISPR depletion strategy to ablate NF expression, we found that the loss of NF selectively perturbed AnkG accumulation and its relative proximal distribution within the AIS. We found that the overexpression of sodium channels could restore AnkG accumulation, but not its altered distribution within the AIS without NF present. We go on to show that although the loss of NF altered AnkG distribution, sodium channel function within the AIS remained normal. Taken together, these results demonstrate that the regulation of AnkG and sodium channel accumulation within the AIS can occur independently of one another, potentially mediated by other binding partners such as NF.