Topography of Native SK Channels Revealed by Force Nanoscopy in Living Neurons
Topography of Native SK Channels Revealed by Force Nanoscopy in Living Neurons
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DOI：
10.1523/jneurosci.1785-12.2012
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发表时间：
2012-08-15
影响因子：
5.3
通讯作者：
Lykotrafitis, George
中科院分区：
文献类型：
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作者：
Maciaszek, Jamie L.;Soh, Heun;Lykotrafitis, George
离子通道的空间分布是神经元兴奋性的重要决定因素。然而，目前还没有定量技术来映射活细胞中具有单通道分辨率的内源性离子通道。在这里，我们证明了药理学与单分子原子力显微镜（AFM）的集成允许在活神经元中的天然钾通道的高分辨率映射。我们专注于钙激活的小电导（SK）钾通道，这在大脑生理学中起着至关重要的作用。通过连接apamin，毒素，特异性结合SK通道，AFM悬臂的尖端，我们能够检测apamin和SK通道之间的结合事件。我们发现，从大鼠海马神经元的本地SK通道主要驻留在树突作为单一实体和成对的。我们还发现SK通道的树突状分布是动态的，并受蛋白激酶A的控制。我们的研究表明，毒素药理学与单分子原子力显微镜的集成可以用来定量映射活细胞中的单个天然离子通道，从而为细胞生理学中的离子通道研究提供了一种新的工具。
The spatial distribution of ion channels is an important determinant of neuronal excitability. However, there are currently no quantitative techniques to map endogenous ion channels with single-channel resolution in living cells. Here, we demonstrate that integration of pharmacology with single-molecule atomic force microscopy (AFM) allows for the high-resolution mapping of native potassium channels in living neurons. We focus on calcium-activated small conductance (SK) potassium channels, which play a critical role in brain physiology. By linking apamin, a toxin that specifically binds to SK channels, to the tip of an AFM cantilever, we are able to detect binding events between the apamin and SK channels. We find that native SK channels from rat hippocampal neurons reside primarily in dendrites as single entities and in pairs. We also show that SK channel dendritic distribution is dynamic and under the control of protein kinase A. Our study demonstrates that integration of toxin pharmacology with single-molecule AFM can be used to quantitatively map individual native ion channels in living cells, and thus provides a new tool for the study of ion channels in cellular physiology.