Chlamydia trachomatis uses host cell dynein to traffic to the microtubule-organizing center in a p50 dynamitin-independent process
Chlamydia trachomatis uses host cell dynein to traffic to the microtubule-organizing center in a p50 dynamitin-independent process
复制标题
DOI：
10.1242/jcs.00695
复制
发表时间：
2003-09-15
影响因子：
4
通讯作者：
Hackstadt, T
中科院分区：
文献类型：
--
作者：
Grieshaber, SS;Grieshaber, NA;Hackstadt, T
衣原体是具有双相发育周期的致病性专性细胞内细菌，其涉及适于细胞外存活（基本体，EB）和细胞内增殖（网状体，RB）的细胞类型。衣原体的细胞内发育完全发生在被称为包涵体的膜结合的液泡内。在进入宿主细胞后2小时内，沙眼衣原体EB被运输到宿主细胞的核周区域，并保持在高尔基体附近，在那里它们开始与含有鞘磷脂的宿主囊泡的子集融合。在这里，我们提供的证据表明，衣原体迁移从细胞周边的高尔基体周围地区类似于宿主细胞囊泡贩运。衣原体向微管的负端移动，并在微管组织中心（MTOC）聚集。在哺乳动物细胞中，最重要的负末端导向微管马达是细胞质动力蛋白。显微注射抗体的细胞质动力蛋白的一个亚基抑制运动的衣原体的MTOC，而显微注射抗体的正向微管电机，驱动蛋白，没有效果。令人惊讶的是，蛋白质p50 dynamitin，一个亚基的dynactin复合物，连接囊泡货物的动力蛋白马达负定向囊泡运输，并没有废除衣原体迁移，即使主机囊泡运输受到抑制。然而，新生衣原体包涵体与P150（（Glued））dynactin亚基共定位，这表明p150（（Glued））可能是动力蛋白激活或持续合成所必需的，但由p50 dynamitin亚基和可能的其他亚基提供的dynactin的货物结合活性不是。由于衣原体转录和翻译所需的这种细胞内运输，衣原体蛋白质修饰的包涵体膜的细胞质面是可能的候选人的蛋白质履行这一功能。
Chlamydiae are pathogenic obligate intracellular bacteria with a biphasic developmental cycle that involves cell types adapted for extracellular survival (elementary bodies, EBs) and intracellular multiplication (reticulate bodies, RBs). The intracellular development of chlamydiae occurs entirely within a membrane-bound vacuole termed an inclusion. Within 2 hours after entry into host cells, Chlamydia trachomatis EBs are trafficked to the perinuclear region of the host cell and remain in close proximity to the Golgi apparatus, where they begin to fuse with a subset of host vesicles containing sphingomyelin. Here, we provide evidence that chlamydial migration from the cell periphery to the peri-Golgi region resembles host cell vesicular trafficking. Chlamydiae move towards the minus end of microtubules and aggregate at the microtubule-organizing center (MTOC). In mammalian cells the most important minus-end-directed microtubule motor is cytoplasmic dynein. Microinjection of antibodies to a subunit of cytoplasmic dynein inhibited movement of chlamydiae to the MTOC, whereas microinjection of antibodies to the plus-directed microtubule motor, kinesin, had no effect. Surprisingly, overexpression of the protein p50 dynamitin, a subunit of the dynactin complex that links vesicular cargo to the dynein motor in minus directed vesicle trafficking, did not abrogate chlamydial migration even though host vesicle transport was inhibited. Nascent chlamydial inclusions did, however, colocalize with the P150((Glued)) dynactin subunit, which suggests that p150((Glued)) may be required for dynein activation or processivity but that the cargo-binding activity of dynactin, supplied by p50 dynamitin subunits and possibly other subunits, is not. Because chlamydial transcription and translation were required for this intracellular trafficking, chlamydial proteins modifying the cytoplasmic face of the inclusion membrane are probable candidates for proteins fulfilling this function.