The non-selective cation-permeable channel TRPC3 is a tetrahedron with a cap on the large cytoplasmic end
The non-selective cation-permeable channel TRPC3 is a tetrahedron with a cap on the large cytoplasmic end
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DOI：
10.1016/j.bbrc.2005.05.181
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发表时间：
2005-08-05
影响因子：
3.1
通讯作者：
Sato, C
中科院分区：
文献类型：
--
作者：
Mio, K;Ogura, T;Sato, C
TRPC3在神经元分化和免疫细胞成熟中起重要作用，它通过调节磷脂酶C激活、钙耗竭和甘油二酯刺激所产生的阳离子电流而发挥重要作用。在这里，我们使用糖基化四聚体纯化了TRPC3通道，并用电子显微镜观察了结构。阴性染色的标本显示均一的蛋白质颗粒含有内腔样结构。这些颗粒图像由自动拾取程序拾取，对齐，并通过生长神经气体网络方法进行分类。类似的定向投影被平均以降低信噪比。平均图像从顶视图前进到侧视图，侧视图代表它们的原始图像。顶视图证实了四区结构的假设，侧视图显示了一个大的细胞质结构域，底部有一个帽状结构，接近预测的离子释放轨迹。蛋白质的总图像是一个200x200x235埃的钝边梯形。凝胶过滤层析获得的斯托克斯半径(92A)也支持TRPC3的这种大尺寸。(C)2005 Elsevier Inc.保留所有权利。
TRPC3 plays important roles in neuronal differentiation and immune cell maturation by mediating the cationic current in response to phospholipase C activation, Ca2+ depletion, and diacylglycerol stimulation. Here, we purified the TRPC3 channel using a glycosylated tetramer and observed the structure using electron microscopy. Negatively stained specimens demonstrate homogeneous protein particles containing an internal cavity-like structure. These particle images were picked up by automated pick-up programs, aligned, and classified by the growing neural gas network method. Similarly oriented projections were averaged to decrease the signal-to-noise ratio. The averaged images progress from the top view to the side views, which are representative of their raw images. The top view confirmed the hypothesis of a four-domain structure, and the side view demonstrates a large cytoplasmic domain with a capped structure at the bottom, which is near a predicted locus of ion release. The total image of the protein is a blunt-edged trapezoid of 200 x 200 x 235 angstrom. This large dimension of TRPC3 is also supported by the Stokes radius (92 A) obtained from gel filtration chromatography. (c) 2005 Elsevier Inc. All rights reserved.