Lakadamyali Melike, Rust Michael J, Babcock Hazen P, Zhuang Xiaowei
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9280-5. doi: 10.1073/pnas.0832269100. Epub 2003 Jul 25.
Influenza is a paradigm for understanding viral infections. As an opportunistic pathogen exploiting the cellular endocytic machinery for infection, influenza is also a valuable model system for exploring the cell's constitutive endocytic pathway. We have studied the transport, acidification, and fusion of single influenza viruses in living cells by using real-time fluorescence microscopy and have dissected individual stages of the viral entry pathway. The movement of individual viruses revealed a striking three-stage active transport process that preceded viral fusion with endosomes starting with an actin-dependent movement in the cell periphery, followed by a rapid, dynein-directed translocation to the perinuclear region, and finally an intermittent movement involving both plus- and minus-end-directed microtubule-based motilities in the perinuclear region. Surprisingly, the majority of viruses experience their initial acidification in the perinuclear region immediately following the dynein-directed rapid translocation step. This finding suggests a previously undescribed scenario of the endocytic pathway toward late endosomes: endosome maturation, including initial acidification, largely occurs in the perinuclear region.
流感是理解病毒感染的一个范例。作为一种利用细胞内吞机制进行感染的机会性病原体，流感也是探索细胞组成型内吞途径的一个有价值的模型系统。我们通过实时荧光显微镜研究了活细胞中单个流感病毒的运输、酸化和融合，并剖析了病毒进入途径的各个阶段。单个病毒的运动揭示了一个显著的三阶段主动运输过程，该过程先于病毒与内体融合，始于细胞周边依赖肌动蛋白的运动，接着是由动力蛋白引导的快速转运至核周区域，最后是在核周区域涉及正向和负向微管运动的间歇性运动。令人惊讶的是，大多数病毒在动力蛋白引导的快速转运步骤之后，立即在核周区域经历其初始酸化。这一发现提示了一种以前未描述的朝向晚期内体的内吞途径情形：内体成熟，包括初始酸化，主要发生在核周区域。
