Crystal structure of Ankyrin-G in complex with a fragment of Neurofascin reveals binding mechanisms required for integrity of the axon initial segment.
Crystal structure of Ankyrin-G in complex with a fragment of Neurofascin reveals binding mechanisms required for integrity of the axon initial segment.
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锚蛋白-G 与神经成束蛋白片段复合物的晶体结构揭示了轴突起始段完整性所需的结合机制
DOI：
10.1016/j.jbc.2022.102272
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发表时间：
2022-09
影响因子：
4.8
通讯作者：
Wang, Chao
中科院分区：
文献类型：
--
作者：
He, Liping;Jiang, Wenli;Li, Jianchao;Wang, Chao
轴突起始段（AIS）在神经元中具有电压门控钠通道（Nav）、细胞粘附分子神经成束蛋白186（Nfasc）和神经元支架蛋白AnkG（AnkG）的特征性密集聚集，其促进动作电位的产生和轴突极性的维持。然而，AIS的组装，维护和可塑性的机制仍然知之甚少。在这里，我们报告的AnkG锚蛋白重复（ANK重复）域的高分辨率晶体结构的复杂性与其结合位点的Nfasc胞质尾，显示，结合亲和力测定与系列截断变体，AnkG-Nfasc结合的分子基础。我们确认AnkG与Nfasc中的FIGQY基序相互作用，并且我们鉴定了它们高亲和力结合所需的另一个区域。我们的结构分析显示，ANK重复序列在AnkG内沟中形成4个疏水或亲水层，这些层与必需的Nfasc残基（包括F1202、E1204和Y1212）协调相互作用。此外，我们显示AnkG-Nfasc复合物的破坏废除了培养的小鼠海马神经元中AIS处的Nfasc富集。最后，我们的结构和生化分析表明，L1综合征相关突变L1 CAM，一个成员的L1免疫球蛋白家族蛋白，包括Nfasc，L1 CAM，NrCAM，和CHL 1，妥协与锚蛋白的结合。总之，这些结果定义了AnkG-Nfasc复合物形成的机制，并表明AIS完整性需要Nfasc的AnkG依赖性聚集。
The axon initial segment (AIS) has characteristically dense clustering of voltage-gated sodium channels (Nav), cell adhesion molecule Neurofascin 186 (Nfasc), and neuronal scaffold protein Ankyrin-G (AnkG) in neurons, which facilitates generation of an action potential and maintenance of axonal polarity. However, the mechanisms underlying AIS assembly, maintenance, and plasticity remain poorly understood. Here, we report the high-resolution crystal structure of the AnkG ankyrin repeat (ANK repeat) domain in complex with its binding site in the Nfasc cytoplasmic tail that shows, in conjunction with binding affinity assays with serial truncation variants, the molecular basis of AnkG–Nfasc binding. We confirm AnkG interacts with the FIGQY motif in Nfasc, and we identify another region required for their high affinity binding. Our structural analysis revealed that ANK repeats form 4 hydrophobic or hydrophilic layers in the AnkG inner groove that coordinate interactions with essential Nfasc residues, including F1202, E1204, and Y1212. Moreover, we show disruption of the AnkG–Nfasc complex abolishes Nfasc enrichment at the AIS in cultured mouse hippocampal neurons. Finally, our structural and biochemical analysis indicated that L1 syndrome-associated mutations in L1CAM, a member of the L1 immunoglobulin family proteins including Nfasc, L1CAM, NrCAM, and CHL1, compromise binding with ankyrins. Taken together, these results define the mechanisms underlying AnkG–Nfasc complex formation and show that AnkG-dependent clustering of Nfasc is required for AIS integrity.
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影响因子：
7.7
作者：
Ghosh A;Malavasi EL;Sherman DL;Brophy PJ
通讯作者：
Brophy PJ
影响因子：
25
作者：
Chang, Kae-Jiun;Zollinger, Daniel R.;Susuki, Keiichiro;Sherman, Diane L.;Makara, Michael A.;Brophy, Peter J.;Cooper, Edward C.;Bennett, Vann;Mohler, Peter J.;Rasband, Matthew N.
通讯作者：
Rasband, Matthew N.
影响因子：
5.3
作者：
Alpizar, Scott A.;Baker, Arielle L.;Hoppa, Michael B.
通讯作者：
Hoppa, Michael B.
DOI：
10.1073/pnas.1416544112
发表时间：
2015-01-27
影响因子：
11.1
作者：
Jenkins, Paul M.;Kim, Namsoo;Bennett, Vann
通讯作者：
Bennett, Vann
影响因子：
25
作者：
Kole, Maarten H. P.;Stuart, Greg J.
通讯作者：
Stuart, Greg J.