Internalization and intracellular trafficking of G protein-coupled receptors (GPCR) plays an important role in the signal transduction. These processes are often highly dynamic and take place rapidly. In the past 10 years, it became obvious that internalized GPCRs are also capable of signaling via arrestin or heterotrimeric G proteins within the endosomal compartment. Real-time imaging of receptors in living cells can help to evaluate the temporal and spatial localization. We achieved a two-color pulse-chase labeling approach, which allowed the tracking of the human neuropeptide Y₂ receptor (hY₂R) in the same cell at different times. The ability to visualize the internalization pathway of two separately labeled and separately stimulated subsets of hY₂R in a time-resolved manner revealed a rapid trafficking. Fusion of the two hY₂R subsets was already observed 10 min after stimulation in the early endosomal compartment without subsequent separation of the fused receptor populations. The results demonstrate that the cells do not discriminate between receptors that were stimulated and internalized at different time points.

中文翻译：

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时间分辨跟踪的两种颜色脉冲追踪分别内在化的神经肽Y ₂受体。

G蛋白偶联受体（GPCR）的内在化和细胞内运输在信号转导中起重要作用。这些过程通常是高度动态的，并且会迅速发生。在过去的十年中，很明显，内在的GPCR还能够通过内体区室中的抑制蛋白或异源三聚体G蛋白发出信号。活细胞中受体的实时成像可以帮助评估时间和空间定位。我们实现了两种颜色的脉冲追踪标记方法，该方法可以跟踪同一细胞在不同时间的人类神经肽Y ₂受体（hY ₂ R）。可视化hY的两个分别标记和分别刺激的子集的内在化途径的能力₂ R以时间分辨的方式显示出人口贩运迅速。在早期的内体区室中刺激后10分钟，已经观察到两个hY ₂ R子集的融合，而没有随后分离融合的受体群。结果表明，细胞不能区分在不同时间点被刺激和内在化的受体。