A Plasmodium phospholipase is involved in disruption of the liver stage parasitophorous vacuole membrane.
A Plasmodium phospholipase is involved in disruption of the liver stage parasitophorous vacuole membrane.
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DOI：
10.1371/journal.ppat.1004760
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发表时间：
2015-03
期刊：
影响因子：
6.7
通讯作者：
Heussler VT
中科院分区：
文献类型：
--
作者：
Burda PC;Roelli MA;Schaffner M;Khan SM;Janse CJ;Heussler VT
细胞内病原体从宿主细胞中协调退出是感染成功和传播的关键过程。虽然磷脂酶已被证明在细菌宿主细胞出口和毒力中发挥重要作用，但它们在释放细胞内真核寄生虫方面的作用在很大程度上是未知的。我们检测了一种具有磷脂酶活性的疟疾寄生虫蛋白，发现它与肝细胞外流有关。在肝细胞中，寄生虫被寄生虫空泡膜(PVM)包围，在寄生虫释放到血液中之前，必须破坏PVM膜。然而，在分子基础上，人们对PVM是如何破裂的知之甚少。我们发现伯氏疟原虫磷脂酶PbPL定位于感染肝细胞的PVM。我们提供的证据表明，缺乏PbPL的寄生虫经历了完全正常的肝期发育，直到产生裂殖子，但从宿主肝细胞的出口存在缺陷。为了进一步研究这一点，我们建立了一种基于活细胞成像的分析方法，使我们能够定量研究PVM破裂的时间动力学。利用这一检测方法，我们可以证明PbPL缺陷的寄生虫表现出PVM破裂受损，导致寄生虫排出延迟。通过基因互补可以重建野生型的表型，证明了PbPL缺失表型的特异性。总之，我们首次发现了一种对PVM破裂和随后寄生虫从受感染的肝细胞中排出至关重要的疟原虫磷脂酶，从而确立了寄生虫磷脂酶在排泄中的关键作用。离开宿主细胞是细胞内病原体的一个关键过程，允许其他细胞成功感染，从而传播感染。疟原虫感染肝细胞和红细胞，在这些细胞内，它们像许多其他细胞内病原体一样被包含在一个液泡中。在寄生虫感染其他细胞之前，周围的寄生液泡膜(PVM)需要破裂。然而，在分子水平上对这一过程知之甚少，到目前为止还没有鉴定出在寄生虫出口过程中介导PVM裂解的疟原虫蛋白。在这项研究中，我们鉴定了一种疟原虫磷脂酶，并证明它定位于肝细胞内寄生虫的PVM。我们证明，缺乏这种蛋白的寄生虫在PVM破裂方面存在缺陷，因此在宿主细胞出口方面也存在缺陷。总之，我们的研究首次表明，磷脂酶在细胞内真核寄生虫的PVM破坏中发挥作用。
The coordinated exit of intracellular pathogens from host cells is a process critical to the success and spread of an infection. While phospholipases have been shown to play important roles in bacteria host cell egress and virulence, their role in the release of intracellular eukaryotic parasites is largely unknown. We examined a malaria parasite protein with phospholipase activity and found it to be involved in hepatocyte egress. In hepatocytes, Plasmodium parasites are surrounded by a parasitophorous vacuole membrane (PVM), which must be disrupted before parasites are released into the blood. However, on a molecular basis, little is known about how the PVM is ruptured. We show that Plasmodium berghei phospholipase, PbPL, localizes to the PVM in infected hepatocytes. We provide evidence that parasites lacking PbPL undergo completely normal liver stage development until merozoites are produced but have a defect in egress from host hepatocytes. To investigate this further, we established a live-cell imaging-based assay, which enabled us to study the temporal dynamics of PVM rupture on a quantitative basis. Using this assay we could show that PbPL-deficient parasites exhibit impaired PVM rupture, resulting in delayed parasite egress. A wild-type phenotype could be re-established by gene complementation, demonstrating the specificity of the PbPL deletion phenotype. In conclusion, we have identified for the first time a Plasmodium phospholipase that is important for PVM rupture and in turn for parasite exit from the infected hepatocyte and therefore established a key role of a parasite phospholipase in egress. Leaving their host cell is a crucial process for intracellular pathogens, allowing successful infection of other cells and thereby spreading of infection. Plasmodium parasites infect hepatocytes and red blood cells, and inside these cells they are contained within a vacuole like many other intracellular pathogens. Before parasites can infect other cells, the surrounding parasitophorous vacuole membrane (PVM) needs to be ruptured. However, little is known about this process on a molecular level and Plasmodium proteins mediating lysis of the PVM during parasite egress have not so far been identified. In this study, we characterize a Plasmodium phospholipase and show that it localizes to the PVM of parasites within hepatocytes. We demonstrate that parasites lacking this protein have a defect in rupture of the PVM and thereby in host cell egress. In conclusion, our study shows for the first time that a phospholipase plays a role in PVM disruption of an intracellular eukaryotic parasite.
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影响因子：
3.7
作者：
Helm S;Lehmann C;Nagel A;Stanway RR;Horstmann S;Llinas M;Heussler VT
通讯作者：
Heussler VT
影响因子：
3.7
作者：
Lin JW;Annoura T;Sajid M;Chevalley-Maurel S;Ramesar J;Klop O;Franke-Fayard BM;Janse CJ;Khan SM
通讯作者：
Khan SM
影响因子：
3.4
作者：
Carey, Allison F.;Singer, Mirko;Amino, Rogerio
通讯作者：
Amino, Rogerio
影响因子：
3.1
作者：
Noronha, FSM;Cruz, JS;Horta, MF
通讯作者：
Horta, MF
影响因子：
4.7
作者：
Graewe, Stefanie;Retzlaff, Silke;Heussler, Volker T.
通讯作者：
Heussler, Volker T.