Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München, Munich, Germany.
PLoS Pathog. 2011 Sep;7(9):e1002283. doi: 10.1371/journal.ppat.1002283. Epub 2011 Sep 29.
Chlamydiae are obligate intracellular bacteria that propagate in a cytosolic vacuole. Recent work has shown that growth of Chlamydia induces the fragmentation of the Golgi apparatus (GA) into ministacks, which facilitates the acquisition of host lipids into the growing inclusion. GA fragmentation results from infection-associated cleavage of the integral GA protein, golgin-84. Golgin-84-cleavage, GA fragmentation and growth of Chlamydia trachomatis can be blocked by the peptide inhibitor WEHD-fmk. Here we identify the bacterial protease chlamydial protease-like activity factor (CPAF) as the factor mediating cleavage of golgin-84 and as the target of WEHD-fmk-inhibition. WEHD-fmk blocked cleavage of golgin-84 as well as cleavage of known CPAF targets during infection with C. trachomatis and C. pneumoniae. The same effect was seen when active CPAF was expressed in non-infected cells and in a cell-free system. Ectopic expression of active CPAF in non-infected cells was sufficient for GA fragmentation. GA fragmentation required the small GTPases Rab6 and Rab11 downstream of CPAF-activity. These results define CPAF as the first protein that is essential for replication of Chlamydia. We suggest that this role makes CPAF a potential anti-infective therapeutic target.
衣原体是一种专性细胞内细菌，在细胞质空泡中繁殖。最近的研究表明，衣原体的生长诱导高尔基体（GA）碎片化成小堆栈，这有利于将宿主脂质摄取到正在生长的包涵体中。GA 碎片化是由与感染相关的完整 GA 蛋白，即 golgin-84 的切割引起的。衣原体属蛋白样活性因子（CPAF）可阻断衣原体内切酶、GA 碎片化和沙眼衣原体的生长。我们在这里鉴定出细菌蛋白酶，作为介导 golgin-84 切割的因子，也是 WEHD-fmk 抑制的靶标。WEHD-fmk 阻断了沙眼衣原体和肺炎衣原体感染过程中 golgin-84 的切割以及已知的 CPAF 靶标的切割。当在非感染细胞中和无细胞系统中表达活性 CPAF 时，也观察到相同的效果。在非感染细胞中异位表达活性 CPAF 足以导致 GA 碎片化。GA 碎片化需要 CPAF 活性下游的小 GTPases Rab6 和 Rab11。这些结果将 CPAF 定义为第一个对衣原体复制至关重要的蛋白质。我们认为，这一作用使 CPAF 成为一种有潜力的抗感染治疗靶点。
