The axon is a long projection connecting a neuron to its targets. Here, the axons of cultured rat cortical neurons were isolated with micropatterned chips that enable the separation of axons from their cell bodies. Proteins extracted from isolated axons and whole neurons were subjected to analyses using two-dimensional liquid chromatography–tandem mass spectrometry (2D-LC–MS/MS) analyses without and with stable isotope dimethyl labeling, resulting in the identification of >2500 axonal proteins and 103 axon-enriched proteins. A strong correlation exists between the abundances of axonal proteins and their counterparts in whole neurons. The proteomic results confirm the axonal protein constituents of the subcellular structures documented in earlier electron microscopic studies. Cortical axons have proteins that are components of machineries for protein degradation and the synthesis of soluble, membrane, and secretory proteins, although axons lack conventional Golgi apparatus. Despite the fact that axons lack nucleus, nuclear proteins were identified, and 67 of them were found enriched in axons. Some of the results obtained by the MS-based studies were validated by quantitative Western blotting and immunofluorescence staining analyses. The results represent the first comprehensive description of the axonal protein landscape. The MS proteomics data are available via ProteomeXchange with identifier PXD005527.

中文翻译：

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培养大鼠皮质神经元轴突的无偏蛋白质组学研究

轴突是将神经元连接到其目标的长投影。在这里，用微模式芯片分离了培养的大鼠皮质神经元的轴突，从而使轴突从它们的细胞体中分离出来。从分离的轴突和整个神经元中提取的蛋白质经过二维液相色谱-串联质谱分析（2D-LC-MS / MS）进行分析，而无和具有稳定的同位素二甲基标记，从而鉴定出> 2500种轴突蛋白质和103轴突富集的蛋白质。在整个神经元中，轴突蛋白的丰度与其对应物之间存在很强的相关性。蛋白质组学结果证实了早期电子显微镜研究中记录的亚细胞结构的轴突蛋白成分。皮质轴突具有蛋白质，这些蛋白质是蛋白质降解以及可溶性，膜和分泌性蛋白质合成的机械设备的组成部分，尽管轴突缺乏常规的高尔基体。尽管轴突缺乏细胞核的事实，但已鉴定出核蛋白，并发现其中67个富含轴突。通过基于MS的研究获得的一些结果已通过定量Western印迹和免疫荧光染色分析得到了验证。结果代表了轴突蛋白景观的第一个全面描述。MS蛋白质组学数据可通过ProteomeXchange获得，其标识符为PXD005527。其中67个被发现富含轴突。通过基于MS的研究获得的一些结果已通过定量Western印迹和免疫荧光染色分析得到了验证。结果代表了轴突蛋白景观的第一个全面描述。MS蛋白质组学数据可通过ProteomeXchange获得，其标识符为PXD005527。其中67个被发现富含轴突。通过基于MS的研究获得的一些结果已通过定量Western印迹和免疫荧光染色分析得到了验证。结果代表了轴突蛋白景观的第一个全面描述。MS蛋白质组学数据可通过ProteomeXchange获得，其标识符为PXD005527。