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Cyclic nucleotide signalling in malaria parasite differentiation

疟疾寄生虫分化中的环核苷酸信号传导

基本信息

批准号：
1618511
负责人：
金额：
--
依托单位：
London School of Hygiene & Tropical Medicine
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1618511
关键词：
Cyclic nucleotide signalling malaria parasite

项目摘要

Strategic Research Priority: World Class BiosciencesAbstract Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) are important signalling molecules which regulate critical events across all stages of the malaria parasite lifecycle. To further our understanding of how this signalling pathway governs important events involved in egress and invasion, this study investigates two different members of this signalling cascade in Plasmodium falciparum parasites.Project Guanylyl Cyclase a (GCa) is a large predicted bifunctional enzyme which is a key component of the signalling pathway. It consists of an ATPase domain, which is thought to flip phospholipids; and a GC domain, which is responsible for generating cGMP. Using the dimerisable Cre recombinase system (DiCre), an inducible GCa knockout line was generated, confirming that GCa is essential and required for egress. GCa-deficient parasites can be rescued by chemically complementing with a cGMP analogue. Although the exact role of the ATPase remains unknown, mutagenesis of this domain indicate that it performs an essential function.Activation of this signalling cascade culminates in the phosphorylation of several effector proteins, many of which form part of the glideosome. This includes the actomyosin motor protein, Myosin A (MyoA), which is phosphorylated at a single site, Ser19. Since the glideosome generates the force required for merozoites to invade host cells, these cGMP-dependent phosphorylation events may be involved in modulating motor activity. A DiCre MyoA knockout line was generated, revealing that MyoA is essential for red blood cell invasion. This conditional KO line was then used to investigate whether phosphorylation of Ser19 is important for motor function by complementing with wild type or mutant versions of the protein that either mimic or ablate phosphorylation of Ser19. In vitro motility assays using material derived from parasites expressing either wildtype or mutant Myosin A were also performed in order to understand the effects of this phosphorylation event on motor activity.

战略研究重点：世界级生物科学摘要环鸟苷一磷酸(CGMP)和环一磷酸腺苷(CAMP)是重要的信号分子，调节疟疾寄生虫生命周期所有阶段的关键事件。为了进一步了解这一信号通路如何调控出口和入侵中的重要事件，本研究研究了恶性疟原虫中这一信号级联的两个不同成员。鸟苷酸环化酶a(GCA)是一个预测的大的双功能酶，是信号通路的关键组成部分。它由一个被认为是翻转磷脂的ATPase结构域和一个负责产生cGMP的GC结构域组成。利用二聚体Cre重组酶系统(DiCre)，获得了一个可诱导的GCA基因敲除系，证实了GCA是植物出口所必需的。缺乏GCA的寄生虫可以通过与cGMP类似物的化学补充来拯救。虽然ATPase的确切作用尚不清楚，但该结构域的突变表明它执行着一项重要的功能。这一信号级联的激活最终导致几种效应蛋白的磷酸化，其中许多蛋白形成了胶质小体的一部分。这包括肌球蛋白A(MyoA)，肌球蛋白A(MyoA)，它在单一的Ser19位点处被磷酸化。由于胶质小体产生裂殖子入侵宿主细胞所需的力量，这些依赖于cGMP的磷酸化事件可能参与调节运动活性。产生了一个DiCre MyoA基因敲除株，揭示了MyoA对红细胞入侵是必不可少的。然后用这个有条件的KO系来研究Ser19的磷酸化是否通过与模拟或去除Ser19的磷酸化的野生型或突变版本的蛋白质互补来对运动功能起重要作用。使用表达野生型或突变型肌球蛋白A的寄生虫的材料进行体外运动分析，以了解这种磷酸化事件对运动活性的影响。