PDF(Pubmed)
Abstract：
The digestion of pathogens inside phagosomes by immune cells occurs through a sequence of reactions including acidification and proteolysis, but how the reactions are orchestrated in the right order is unclear due to a lack of methods to simultaneously measure more than one reaction in phagosomes. Here we report a bifunctional Janus-particle probe to simultaneously monitor acidification and proteolysis in single phagosomes in live cells. Each probe consists of a pH reporter and a proteolysis reporter that are spatially separated but function concurrently. Using the Janus probes, we found the acidic pH needed to initiate and maintain proteolysis, revealing the mechanism for the sequential occurrence of both reactions during pathogen digestion. We showed how bacterium-derived lipopolysaccharides alter the acidification and proteolysis in phagosomes. This study showcases Janus-particle probes as a generally applicable tool for monitoring multiple reactions in intracellular vesicles.
摘要：
免疫细胞消化吞噬体内的病原体是通过一系列反应发生的，包括酸化和蛋白水解，但是，由于缺乏同时测量吞噬体中一个以上反应的方法，这些反应是如何按正确的顺序编排的，目前尚不清楚。在这里，我们报告了一种双功能Janus颗粒探针，可同时监测活细胞中单个吞噬体中的酸化和蛋白水解。每个探针由在空间上分开但同时起作用的pH报告物和蛋白水解报告物组成。使用Janus探测器,我们发现启动和维持蛋白水解所需的酸性pH值，揭示了病原体消化过程中两种反应相继发生的机制。我们展示了细菌来源的脂多糖如何改变吞噬体中的酸化和蛋白水解。这项研究展示了Janus颗粒探针作为监测细胞内囊泡中多个反应的普遍适用工具。
