Abstract：
The evolution of ion channel clustering at nodes of Ranvier enabled the development of complex vertebrate nervous systems. At mammalian nodes, the K+ leak channels TRAAK and TREK-1 underlie membrane repolarization. Despite the molecular similarities between nodes and the axon initial segment (AIS), TRAAK and TREK-1 are reportedly node-specific, suggesting a unique clustering mechanism. However, we show that TRAAK and TREK-1 are enriched at both nodes and AIS through a common mechanism. We identified a motif near the C-terminus of TRAAK that is necessary and sufficient for its clustering. The motif first evolved among cartilaginous fish. Using AnkyrinG (AnkG) conditional knockout mice, CRISPR/Cas9-mediated disruption of AnkG, co-immunoprecipitation, and surface recruitment assays, we show that TRAAK forms a complex with AnkG and that AnkG is necessary for TRAAK\'s AIS and nodal clustering. In contrast, TREK-1\'s clustering requires TRAAK. Our results expand the repertoire of AIS and nodal ion channel clustering mechanisms and emphasize AnkG\'s central role in assembling excitable domains.
摘要：
Ranvier节点上离子通道簇的演化使复杂的脊椎动物神经系统得以发展。在哺乳动物节点，K+泄漏通道TRAAK和TREK-1位于膜复极化之下。尽管节点和轴突初始片段(AIS)之间存在分子相似性，据报道，TRAAK和TREK-1是特定于节点的，提出了一种独特的聚类机制。然而,我们表明TRAAK和TREK-1通过共同的机制在两个节点和AIS上都得到了丰富。我们确定了TRAAKC末端附近的基序，这对于其聚类是必要且足够的。该主题首先在软骨鱼中进化。使用AnkyrinG（AnkG）条件敲除小鼠，CRISPR/Cas9介导的AnkG破坏，免疫共沉淀,和表面募集化验，我们证明TRAAK与AnkG形成一个复合体，AnkG对于TRAAK的AIS和节点聚类是必需的。相比之下,TREK-1的群集需要TRAAK。我们的结果扩展了AIS和节点离子通道聚类机制的库，并强调了AnkG在组装可兴奋域中的核心作用。
