Rapid and convenient detection of protein–protein interactions (PPIs) is of great significance for understanding function of protein. For efficiently detecting PPIs, we used the changes of proteins fluorescence localization to design a novel system, fluorescence translocation co-localization (FTCL), based on nuclear localization signal (NLS) in living cells. Depending on the original state of protein localization (both in the cytoplasm, both in the nucleus, one in the nucleus and another in the cytoplasm), two target proteins can be partitioned into the cytoplasm and nucleus by adding a NLS or mutating an existing NLS. Three independent results display that the changes of protein fluorescence co-localization were observed following co-expression of the two target proteins. At the same time, we verified the accuracy of fluorescence co-localization by co-immunoprecipitation. There FTCL system provided a novel detection method for PPIs, regardless of protein localization in the nucleus or cytoplasm. More importantly, this study provides a new strategy for future protein interaction studies through organelle localization (such as mitochondria, Golgi and cytomembrane, etc.).

中文翻译：

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一种基于荧光共定位快速检测蛋白质-蛋白质相互作用 (PPI) 的新系统

快速方便地检测蛋白质-蛋白质相互作用（PPI）对于理解蛋白质的功能具有重要意义。为了有效检测 PPI，我们利用蛋白质荧光定位的变化设计了一种新的系统，即基于活细胞核定位信号 (NLS) 的荧光易位共定位 (FTCL)。根据蛋白质定位的原始状态（都在细胞质中，都在细胞核中，一个在细胞核中，另一个在细胞质中），可以通过添加 NLS 或突变现有的 NLS 将两种靶蛋白分配到细胞质和细胞核中. 三个独立的结果表明，在两种靶蛋白共表达后观察到蛋白质荧光共定位的变化。同时，我们通过免疫共沉淀验证了荧光共定位的准确性。FTCL 系统为 PPI 提供了一种新的检测方法，无论蛋白质在细胞核或细胞质中的定位如何。更重要的是，该研究为未来通过细胞器定位（如线粒体、高尔基体和细胞膜等）的蛋白质相互作用研究提供了新的策略。