Novel subcellular distribution pattern of A-type K+ channels on neuronal surface.
Novel subcellular distribution pattern of A-type K+ channels on neuronal surface.
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神经元表面A型K+通道的新型亚细胞分布模式。
DOI：
10.1523/jneurosci.5257-05.2006
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发表时间：
2006-03-08
影响因子：
5.3
通讯作者：
Nusser, Zoltan
中科院分区：
文献类型：
--
作者：
Kollo, Mihaly;Holderith, Noemi B;Nusser, Zoltan
钾通道构成了最多样的离子通道家族。在神经细胞中，它们在突触整合和输出产生中的关键作用已经被证明。在这里，我们为预测K+通道在中枢神经系统中的新作用的分布提供了证据。我们的实验揭示了Kv4.3A型K+通道亚单位在攀爬纤维和小脑GABA能中间神经元之间的特殊连接处高度选择性地聚集。高分辨率超微结构和免疫组织化学实验表明，这些连接不同于已知的化学和电(缝隙连接)突触，也不同于粘附点。每个小脑中间神经元都含有许多这样的富含K+通道的特化细胞，它们似乎分布在整个躯体树突表面。我们还表明，这种富含K+通道的特化不仅存在于小脑，而且广泛存在于大鼠中枢神经系统。例如，主嗅球的二尖瓣细胞彼此之间建立Kv4.2亚单位阳性的专门化。在这些特化中，两个相对的膜都有高密度的K+通道，表明双向信号转导。缰核内侧核的神经细胞之间也观察到类似的特化，Kv4.2和4.3亚基明显共同聚集。根据我们的结果和已知的A型K+通道的特性，我们认为在独特的膜特化上策略性地聚集K+通道可能介导一种新型的神经细胞之间的通讯。
Potassium channels comprise the most diverse family of ion channels. In nerve cells, their critical roles in synaptic integration and output generation have been demonstrated. Here, we provide evidence for a distribution that predicts a novel role of K+ channels in the CNS. Our experiments revealed a highly selective clustering of the Kv4.3 A-type K+ channel subunits at specialized junctions between climbing fibers and cerebellar GABAergic interneurons. High-resolution ultrastructural and immunohistochemical experiments demonstrated that these junctions are distinct from known chemical and electrical (gap junctions) synapses and also from puncta adherentia. Each cerebellar interneuron contains many such K+ channel-rich specializations, which seem to be distributed throughout the somatodendritic surface. We also show that such K+ channel-rich specializations are not only present in the cerebellum but are widespread in the rat CNS. For example, mitral cells of the main olfactory bulb establish Kv4.2subunit-positive specializations with each other. At these specializations, both apposing membranes have a high density of K+ channels, indicating bidirectional signaling. Similar specializations with pronounced coclustering of the Kv4.2 and 4.3 subunits were observed between nerve cells in the medial nucleus of the habenula. Based on our results and on the known properties of A-type K+ channels, we propose that strategically clustered K+ channels at unique membrane specializations could mediate a novel type of communication between nerve cells.