Functional characterization of phospholipases in the malaria parasite Plasmodium falciparum

疟疾寄生虫恶性疟原虫中磷脂酶的功能特征

• 批准号: 414222880
• 负责人: Dr. Paul-Christian Burda
• 金额: --
• 依托单位: Zentrum für strukturelle Systembiologie (CSSB)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/414222880?language=en
• 关键词: Functional; characterization; phospholipases; malaria; parasite

Plasmodium parasites, the causative agents of malaria, infect hepatocytes and red blood cells (RBCs). Within these cells, parasites are surrounded by a parasitophorous vacuole membrane (PVM). Consequently, for their release from host cells and to propagate their infection, parasites have to disrupt the PVM and the host cell membrane. How this membrane rupture occurs on a molecular level and how it is controlled is only partially understood and only a very limited number of parasite proteins involved in this process have been identified so far. We previously showed that a parasite phospholipase mediates PVM rupture during parasite egress from hepatocytes. Whether parasite phospholipases are similarly involved in parasite release from RBCs is not known and most of the Plasmodium phospholipases are not characterized. In this project, it is thus proposed to functionally analyze the role of phospholipases of the human malaria parasite Plasmodium falciparum during its development within red blood cells. First, we will probe into the redundancy of those enzymes that show expression in asexual blood stage parasites by targeted gene disruption. Essential genes, which cannot be deleted using conventional knockout techniques, will further be analyzed using conditional systems, their loss-of-function phenotypes analyzed and their cellular localization elucidated. In order to reveal a potential interplay and synergistic functions between different phospholipases, double knockout parasites targeting a subset of enzymes will be generated and analyzed. Finally, we aim to investigate, whether parasite phospholipases are activated by proteolytic cleavage of the egress-associated subtilisin-like serine protease SUB1. For this, the functional importance of predicted SUB1 cleavage sites identified in several putative phospholipases will be tested. In conclusion, our work will increase our knowledge of the molecular machinery leading to parasite release from host cells and might lead to the identification of novel targets for parasite-specific intervention strategies.

疟疾寄生虫是疟疾的病原体，可感染肝细胞和红细胞 (RBC)。在这些细胞内，寄生虫被寄生液泡膜（PVM）包围。因此，为了从宿主细胞中释放并传播感染，寄生虫必须破坏 PVM 和宿主细胞膜。这种膜破裂如何在分子水平上发生以及如何控制它仅被部分了解，并且迄今为止仅鉴定了非常有限数量的参与该过程的寄生虫蛋白。我们之前表明，寄生虫磷脂酶在寄生虫从肝细胞排出过程中介导 PVM 破裂。寄生虫磷脂酶是否同样参与红细胞中寄生虫的释放尚不清楚，并且大多数疟原虫磷脂酶尚未被表征。因此，在该项目中，建议对人类疟原虫恶性疟原虫磷脂酶在红细胞内发育过程中的作用进行功能分析。首先，我们将通过靶向基因破坏来探讨那些在无性血液阶段寄生虫中表达的酶的冗余。无法使用传统敲除技术删除的必需基因将使用条件系统进行进一步分析，分析其功能丧失表型并阐明其细胞定位。为了揭示不同磷脂酶之间潜在的相互作用和协同功能，将生成并分析针对酶子集的双敲除寄生虫。最后，我们的目的是研究寄生虫磷脂酶是否被出口相关的枯草杆菌蛋白酶样丝氨酸蛋白酶 SUB1 的蛋白水解裂解所激活。为此，将测试在几种假定的磷脂酶中鉴定的预测 SUB1 切割位点的功能重要性。总之，我们的工作将增加我们对导致寄生虫从宿主细胞释放的分子机制的了解，并可能导致确定寄生虫特异性干预策略的新靶标。