Identification of a minimal segment of complexin II essential for preferential distribution in axons
Identification of a minimal segment of complexin II essential for preferential distribution in axons
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DOI：
10.1111/j.1471-4159.2009.05874.x
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发表时间：
2009-03-01
影响因子：
4.7
通讯作者：
Takahashi, Masami
中科院分区：
文献类型：
--
作者：
Kataoka, Masakazu;Sekiguchi, Mariko;Takahashi, Masami
复合蛋白II(CPLX2)是一种可溶的突触前蛋白，被认为调节突触前终末的神经递质释放。CPLX2在成熟脑中定位于突触前终末，但其选择性定位机制尚不清楚。在这里，我们确定了CPLX2的一个优先轴突分布的必要片段。在培养的大鼠海马神经元中表达MYC标记的CPLX2，并通过免疫细胞化学和图像分析比较其在轴突和树突之间的分布。在轴突和树突中都检测到了荧光信号，但它们各自的分布差异很大。尽管信号强度从树突的底部到顶端几乎呈线性下降，但沿着轴突，即使在靠近顶端的位置，信号强度也保持在相当高的水平。用一系列突变体进行的图像分析表明，与N-乙基马来酰亚胺敏感因子结合蛋白受体蛋白结合的“中心核心”中19个氨基酸残基G71-p89的缺失导致了优先轴突分布的丧失。与G71-p89片段融合的增强型绿色荧光蛋白衍生物与野生型CPLX2的定位相似，表明CPLX2的G71-p89区域是优先轴突分布的必要条件和充分条件。
Complexin II (CPLX2) is a soluble pre-synaptic protein believed to regulate neurotransmitter release from pre-synaptic terminals. CPLX2 is localized in pre-synaptic terminals in mature brain, but the mechanism of selective localization remains unclear. Here we identified an essential segment of CPLX2 for preferential axonal distribution. Myc-tagged CPLX2 was expressed in cultured rat hippocampal neurons and its distribution between axons and dendrites was compared by immunocytochemistry and image analysis. Fluorescence signals were detected in both axons and dendrites; however, their respective distribution varied significantly. Despite the fact that signal intensity decreased almost linearly from the base to the tip of the dendrite, a substantial level was sustained along the axon, even at a position near the tip. Image analyses using a series of mutants indicated that the deletion of 19 amino acid residues, G71-P89, within the 'central core' for binding to soluble N-ethylmaleimide sensitive factor attachment protein receptor proteins resulted in the loss of preferential axonal distribution. The enhanced green fluorescent protein derivative fused with the G71-P89 fragment exhibited a similar localization to that of wild type CPLX2, indicating that the G71-P89 region of CPLX2 is essential and sufficient for preferential axonal distribution.