The components of an electrical synapse as revealed by expansion microscopy of a single synaptic contact.
The components of an electrical synapse as revealed by expansion microscopy of a single synaptic contact.
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通过单个突触接触的扩展显微镜揭示的电突触的组成部分。
DOI：
10.1101/2023.07.25.550347
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Pereda,AlbertoE
中科院分区：
文献类型：
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作者：
Cárdenas-García,SandraP;Ijaz,Sundas;Pereda,AlbertoE
大多数神经系统结合了联合收割机和直接细胞间通讯，分别称为“化学”和“电”突触。化学突触可以通过它们的多种结构成分来识别。另一方面，电突触通常由两个神经元过程之间的“间隙连接”（细胞间通道簇）的存在来定义。然而，虽然间隙连接提供了通信机制，但尚不清楚电传输是否需要额外的细胞结构的贡献。我们研究了这个问题，在可识别的单一突触接触的斑马鱼Mauthner细胞，在间隙连接共存的神经递质释放的专业化和接触明确定义的解剖学限制的突触。这些单接触的扩展显微镜揭示了与各种突触结构有关的蛋白质的发病率和空间分布的详细地图。不同大小的多个缝隙连接通过其分子组分的存在来鉴定。值得注意的是，大部分突触接触的表面被交错的间隙连接和粘附连接的组件所占据，这表明这两个结构之间存在密切的功能关联。相比之下，谷氨酸受体仅限于接触的小的外围部分，表明大部分突触区域作为电突触发挥作用。因此，我们的研究结果揭示了电突触的总体组织，其与不是一个而是多个间隙连接一起工作，与已知为粘附连接组件的结构和信号分子密切相关。这些细胞间结构之间的关系将有助于建立在整个动物连接体中发现的电突触的边界，并提供洞察电突触的结构组织和功能多样性。
Most nervous systems combine both transmitter-mediated and direct cell–cell communication, known as ‘chemical’and ‘electrical’synapses, respectively. Chemical synapses can be identified by their multiple structural components. Electrical synapses are, on the other hand, generally defined by the presence of a ‘gap junction’(a cluster of intercellular channels) between two neuronal processes. However, while gap junctions provide the communicating mechanism, it is unknown whether electrical transmission requires the contribution of additional cellular structures. We investigated this question at identifiable single synaptic contacts on the zebrafish Mauthner cells, at which gap junctions coexist with specializations for neurotransmitter release and where the contact unequivocally defines the anatomical limits of a synapse. Expansion microscopy of these single contacts revealed a detailed map of the incidence and spatial distribution of proteins pertaining to various synaptic structures. Multiple gap junctions of variable size were identified by the presence of their molecular components. Remarkably, most of the synaptic contact’s surface was occupied by interleaving gap junctions and components of adherens junctions, suggesting a close functional association between these two structures. In contrast, glutamate receptors were confined to small peripheral portions of the contact, indicating that most of the synaptic area functions as an electrical synapse. Thus, our results revealed the overarching organization of an electrical synapse that operates with not one, but multiple gap junctions, in close association with structural and signaling molecules known to be components of adherens junctions. The relationship between these intercellular structures will aid in establishing the boundaries of electrical synapses found throughout animal connectomes and provide insight into the structural organization and functional diversity of electrical synapses.