The role of polyphosphate in Toxoplasma gondii

聚磷酸盐在弓形虫中的作用

• 批准号: 10681078
• 负责人: Silvia N Moreno
• 金额: $ 21.28万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-13 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10681078
• 关键词: AIDS-Related Opportunistic Infections; Address; Alkalinization; Bacteria; Binding; Bioinformatics; Calcium; Catalogs; Catalytic Domain; Cells; Cellular Metabolic Process; Cellular Stress; Client; Complex; Cryptosporidiosis; Cryptosporidium; Cyst; Cytolysis; Cytosol; Data; Diatoms; Disease; Electrostatics; Energy-Generating Resources; Enzymes; Eukaryota; Experimental Designs; Future; Gene Expression; Genome; Heat Stress Disorders; Homologous Gene; Human; Immune response; Immunocompromised Host; Infection; Ions; Knowledge; Link; Liquid substance; Lytic Phase; Malaria; Mammalian Cell; Modification; Molecular Chaperones; Morbidity - disease rate; Names; Orthologous Gene; Parasites; Pathogenesis; Pathogenicity; Pathway interactions; Persons; Phase; Plasmodium; Play; Polymers; Polyphosphates; Polyps; Population; Post-Translational Protein Processing; Process; Proteins; Proteome; Regulation; Role; Rupture; Saccharomyces cerevisiae; Signal Transduction; System; Testing; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Vacuole; Vertebrate Biology; Vertebrates; Virulence; Virulence Factors; Yeasts; acute infection; biological adaptation to stress; chronic infection; cohort; forgetting; fungus; human disease; inorganic phosphate; knock-down; member; metal chelator; mortality; mutant; novel; response; scaffold; validation studies

PROJECT SUMMARY/ABSTRACT Apicomplexan parasites cause persistent mortality and morbidity worldwide through diseases like malaria, toxoplasmosis, and cryptosporidiosis. The phylum member Toxoplasma gondii alone infects approximately one third of the world population. The pathogenesis of T. gondii is reliant on its capacity to replicate within host cells and spread to other host cells. The acute infection is ultimately controlled by the host immune response and the parasite establishes a chronic infection characterized by the presence of tissue cysts containing slow replicating bradyzoites. Tissue cyst rupture releases bradyzoites that convert into tachyzoites that replicate fast and if the host is immunocompromised, could cause severe and even fatal tissue damage. We propose to study how polyphosphate (polyP), a “forgotten molecule”, exerts its role in pathogenicity and virulence of T. gondii. PolyP is a ubiquitous polymer of three to hundreds of phosphate residues linked by high-energy phosphoanhydride bonds and can reach millimolar levels in protozoan parasites, while the concentration in host cells is at the micromolar level. T. gondii stores polyP at molar levels in acidocalcisomes which are hydrolyzed upon alkalinization followed by release of Ca2+ into the cytosol. It is puzzling how little is known about the function of polyP in the T. gondii infection cycle and/or virulence. However, characterizing how polyP functions will impact our knowledge of the mechanism by which T. gondii causes disease. Both in bacteria and eukaryotes polyP is involved in a large number of diverse and apparently unrelated functions. However, these apparently unrelated functions may be the result of polyP’s ability to interact with proteins either electrostatically or covalently and we propose to test this for T. gondii. Our hypothesis is that polyP exerts its essential function in the lytic cycle of T. gondii through its interaction with proteins and/or their covalent modification by polyphosphorylation. We propose two strategies to determine how polyP exerts its role in virulence. To define candidate proteins that interact with polyP we will use Thermal Proteome Profiling and expose intact parasites and/or lysates to heat stress to underscore the role of polyP as a protein-like chaperone. We will also use a bioinformatics approach to discover potential proteins that are covalently modified by polyP. We propose to use polyP mutants (that do not make polyP) already available for the characterization of the role of polyP interaction with target proteins. The synthesis of polyP represents a novel target as it is essential, and the enzymes are absent in the mammalian host. The proteins involved in polyP synthesis are conserved in other apicomplexan parasites. The polyP target proteins will be specific for T. gondii virulence pathways and could have orthologs in other apicomplexans. Additionally, findings from this project could have wider impact for vertebrate biology since the mammalian polyP synthesis machinery is unknown and our findings may uncover novel functions and proteins.

项目摘要/摘要 Apicomplexan寄生虫通过疟疾等疾病在全球范围内持续的死亡和发病率， 弓形虫病和隐孢子虫病。单独感染的门弓形虫弓形虫弓形虫大约感染 世界三分之一的人口。 T. gondii的发病机理是根据其在内部复制的能力负责的 宿主细胞并扩散到其他宿主细胞。急性感染最终由宿主免疫控制 反应和寄生虫建立了以组织囊肿的存在为特征的慢性感染 包含缓慢复制的曲二氮族。组织囊肿破裂释放到转化为tachyzoites的胸肌 这会快速复制，如果宿主是免疫功能低下的，可能会造成严重甚至致命的组织损害。 我们建议研究“遗忘分子”多磷酸（息肉）如何在致病性中发挥作用 和T. gondii的病毒。息肉是连接的三到数百种磷酸盐残留物的无处不在的聚合物 通过高能磷酸氢键，可以在原生动物寄生虫中达到毫米水平 宿主细胞中的浓度为微摩尔水平。 T. gondii将息肉存储在酸性酸性的摩尔水平 在碱化后水解，然后将Ca2+释放到细胞质中。这是难题 已经知道息肉在巨霉菌感染周期和/或病毒中的功能。但是，表征 息肉功能如何影响我们对T. gondii引起疾病的机制的了解。 在细菌和真核生物中，息肉都参与了大量潜水员，并且显然无关 功能。但是，这些显然无关的功能可能是息肉与互动能力的结果 蛋白质是静电或共价，我们建议对T. gondii进行测试。我们的假设是 息肉通过与蛋白质的相互作用在T. gondii的裂解周期中发挥其必不可少的功能 和/或它们通过多磷酸化的共价修饰。 我们提出了两种策略，以确定息肉如何在病毒中发挥作用。定义候选蛋白 与息肉相互作用，我们将使用热蛋白质组分析，并将完整的寄生虫和/或裂解物暴露于 热应激以强调息肉作为蛋白质样伴侣的作用。我们还将使用生物信息学 发现潜在蛋白质的方法是通过息肉共价修饰的。我们建议使用息肉 突变体（没有使息肉）已经可用于表征息肉相互作用与 靶蛋白。息肉的合成代表了一个新的靶标，因为它是必不可少的，并且没有酶 在哺乳动物宿主中。参与息肉合成的蛋白质在其他Apicomplexan中保守 寄生虫。息肉靶蛋白将针对T. gondii病毒途径特异性，并且可能具有直系同源物 在其他apicomplexans中。此外，该项目的发现可能会对脊椎动物生物学产生更大的影响 由于哺乳动物息肉合成机械尚不清楚，我们的发现可能会发现新功能 和蛋白质。