Cell Biology Institute, University of Bonn, Ulrich-Haberland-Strasse 61a, 53121 Bonn, Germany.
Proc Natl Acad Sci U S A. 2010 Nov 30;107(48):20726-31. doi: 10.1073/pnas.1007295107. Epub 2010 Nov 11.
Uptake of microorganisms by professional phagocytic cells leads to formation of a new subcellular compartment, the phagosome, which matures by sequential fusion with early and late endocytic compartments, resulting in oxidative and nonoxidative killing of the enclosed microbe. Few tools are available to study membrane fusion between phagocytic and late endocytic compartments in general and with pathogen-containing phagosomes in particular. We have developed and applied a fluorescence microscopy assay to study fusion of microbe-containing phagosomes with different-aged endocytic compartments in vitro. This revealed that fusion of phagosomes containing nonpathogenic Escherichia coli with lysosomes requires Rab7 and SNARE proteins but not organelle acidification. In vitro fusion experiments with phagosomes containing pathogenic Salmonella enterica serovar Typhimurium indicated that reduced fusion of these phagosomes with early and late endocytic compartments was independent of endosome and cytosol sources and, hence, a consequence of altered phagosome quality.
专业吞噬细胞摄取微生物会导致形成一个新的细胞内隔室，即吞噬体，它通过与早期和晚期内体的连续融合而成熟，从而实现对被包裹微生物的氧化和非氧化杀伤。目前很少有工具可用于研究吞噬细胞和晚期内体之间的膜融合，特别是包含病原体的吞噬体。我们开发并应用了荧光显微镜检测法来研究体外含菌吞噬体与不同年龄的内体之间的融合。结果表明，含有非致病性大肠杆菌的吞噬体与溶酶体的融合需要 Rab7 和 SNARE 蛋白，但不需要细胞器酸化。用含有致病性沙门氏菌肠炎血清型 Typhimurium 的吞噬体进行的体外融合实验表明，这些吞噬体与早期和晚期内体的融合减少与内体和细胞质来源无关，因此是吞噬体质量改变的结果。
