Dissecting the role of Toxoplasma CDPK3 in parasite propagation and virulence

剖析弓形虫 CDPK3 在寄生虫繁殖和毒力中的作用

• 批准号: 9003023
• 负责人: Gustavo A Arrizabalaga
• 金额: $ 23.4万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-02 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9003023
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Affect; Amino Acids; Animals; Attention; Biotin; Brain; Calcium; Calcium Signaling; Cells; Cessation of life; Chronic; Cryptosporidium; Cyst; Defect; Development; Disease; Drug Targeting; Encephalitis; Enzymes; Event; Exhibits; Exposure to; Family; Goals; HIV; Health; Heart; Human; Immune response; Immunocompromised Host; Individual; Infection; Infectious Agent; Ionophores; Knock-out; Lead; Life Cycle Stages; Ligase; Light; Lytic Phase; Malaria; Mammalian Cell; Missense Mutation; Modeling; Mus; Mutation; Names; Parasite Control; Parasites; Patients; Pharmaceutical Preparations; Phenotype; Phosphorylation; Phosphotransferases; Plants; Plasmodium falciparum; Play; Population; Process; Proteins; Recombinants; Research; Resistance; Role; Rupture; Serine; Signal Transduction; Signaling Protein; Spleen; Staging; Testing; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Virulence; Work; base; calcium-dependent protein kinase; cell motility; combat; extracellular; genetic approach; in vitro Assay; in vivo; insight; killings; mutant; new therapeutic target; novel; novel therapeutics; obligate intracellular parasite; pathogen; protein phosphatase 2C; protein protein interaction; release of sequestered calcium ion into cytoplasm; research study; response; signal processing; tissue culture

 DESCRIPTION (provided by applicant): Toxoplasma gondii is an obligate intracellular parasite known to chronically infect a third of the human population. T. gondii is an opportunistic infectious agent that can cause encephalitis and other severe manifestations in AIDS patients. Events required for T. gondii invasion, egress and motility are regulated by calcium signaling processes that include proteins and factors significantly divergent from those of the human host. To exploit these events as potential drug targets would require a better understanding of T. gondii's calcium signaling cascades. A particular family of calcium dependent protein kinases (CDPKs) has garnered special attention, as it is absent from human cells and it is involved in key processes. Through a forward genetic approach we discovered that mutations in TgCDPK3 lead to a delay in calcium ionophore-induced egress (iiEgress), and importantly a defect in the formation of latent stages in the brains of mice. Utilizing a novel screen for protein-protein interactions, we identified several proteins that might act as functional partners or substrates of TgCDPK3, including a protein phosphatase 2C, which we have named TgPP2C4 and another calcium dependent protein kinase TgCDPK2a. It is our hypothesis that TgCDPK3, TgCDPK2a, and TgPP2C4, form part of a "co-regulatory" network essential for parasite virulence. Our first goal will be to analyze the localization and function of both TgPP2C4 and TgCDPK2a. In addition, we will determine the substrates and functional partners of these two enzymes, which will allow us to define the events and proteins co-regulated by TgCDPK3, TgCDPK2a and TgPP2C4. Our second goal will be to determine the role of TgCDPK3 in virulence. This will be accomplished by analyzing the in vivo dissemination and encystation of parasites lacking TgCDPK3 or its co-regulatory partners TgCDPK2 and TgPP2C. Furthermore, we will identify the substrates of TgCDPK3 during the process of encystation in tissue culture, which will provide mechanistic insight into the function of TgCDPK3 during in vivo propagation and development. In conjunction, our work will shed light on the function of calcium signaling during the life cycle of T. gondii and has the potential to reveal novel targets to combat both acute and chronic toxoplasmosis.

 描述（由申请人提供）：弓形虫是一种专性细胞内寄生虫，已知可长期感染三分之一的人群。弓形虫是一种机会性传染原，可导致艾滋病患者出现脑炎和其他严重症状。弓形虫的入侵、排出和运动受到钙信号传导过程的调节，其中包括与人类宿主显着不同的蛋白质和因子，以利用这些事件作为潜在的药物。目标需要更好地了解弓形虫的钙信号级联反应，钙依赖性蛋白激酶（CDPK）的特殊家族引起了特别关注，因为它不存在于人类细胞中，并且通过正向遗传方法参与关键过程。我们发现，TgCDPK3 的突变会导致钙离子载体诱导的流出 (iiEgress) 延迟，而且重要的是，利用一种新的筛选方法，会导致小鼠大脑中潜伏期形成的缺陷。通过蛋白质-蛋白质相互作用，我们鉴定了几种可能作为功能伙伴或底物的蛋白质 TgCDPK3，包括蛋白磷酸酶 2C（我们将其命名为 TgPP2C4）和另一种钙依赖性蛋白激酶 TgCDPK2a，我们假设 TgCDPK3、TgCDPK2a 和 TgPP2C4 构成了寄生虫毒力所必需的“共同调节”网络的一部分。目标是分析 TgPP2C4 和 TgCDPK2a 的定位和功能。此外，我们将确定这两种酶的底物和功能伙伴，这将使我们能够定义 TgCDPK3、TgCDPK2a 和 TgPP2C4 共同调节的事件和蛋白质。我们的第二个目标是确定 TgCDPK3 在毒力中的作用。将通过分析缺乏 TgCDPK3 或其共同调控伙伴 TgCDPK2 和 TgPP2C 的寄生虫的体内传播和成囊来完成。我们将在组织培养的包囊过程中鉴定 TgCDPK3 的底物，这将为 TgCDPK3 在体内繁殖和发育过程中的功能提供机制见解。同时，我们的工作将揭示钙信号在生命过程中的功能。循环 弓形虫的研究，并有可能揭示对抗急性和慢性弓形虫病的新靶点。

项目成果

A minimalistic approach to develop new anti-apicomplexa polyamines analogs.

开发新的抗 apicomplexa 多胺类似物的简约方法。

• 发表时间: 2018-01-01
• 影响因子: 6.7
• 作者: Panozzo;Porta, Exequiel O J;Arrizabalaga, Gustavo;Fargnoli, Lucía;Khan, Shabana I;Tekwani, Babu L;Labadie, Guillermo R
• 通讯作者: Labadie, Guillermo R