Calcium signaling in the parasitophorous vacuole of Toxoplasma gondii

弓形虫寄生液泡中的钙信号传导

• 批准号: 9058486
• 负责人: Gustavo A Arrizabalaga
• 金额: $ 23.38万
• 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: 2015-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9058486
• 关键词: Acquired Immunodeficiency Syndrome; Animals; Bioinformatics; Biotin; Blood; Calcium; Calcium Signaling; Calcium-Binding Proteins; Calmodulin; Candidate Disease Gene; Cells; Centers for Disease Control and Prevention (U.S.); Communication; Complement; Congenital Abnormality; Cytoplasm; Cytoplasmic Granules; Cytoskeleton; Cytosol; Disease; Drug Targeting; EF Hand Motifs; EF-Hand Domain; Event; Health; Human; Immunocompromised Host; Individual; Ion Channel; Label; Ligase; Light; Lytic; Lytic Phase; Membrane; Membrane Proteins; Methods; Microbe; Nutrient; Nutritional Requirements; Organelles; Organism; Parasites; Parasitic Diseases; Pathogenesis; Pathway interactions; Patients; Peptide Signal Sequences; Phenotype; Physiological; Play; Population; Positioning Attribute; Process; Protein Kinase C; Proteins; Proteomics; Regulation; Role; SHPS-1 protein; Signal Pathway; Signal Transduction; Signaling Protein; Testing; Therapeutic; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Translating; Vacuole; Work; base; calcium-dependent protein kinase; cell motility; in utero; interest; mutant; neglect; new therapeutic target; novel; novel strategies; nutrition; obligate intracellular parasite; pathogen; protein protein interaction; release of sequestered calcium ion into cytoplasm; research study; signal processing

 DESCRIPTION (provided by applicant): Toxoplasma gondii, is an obligate intracellular parasite known to chronically infect a third of the human population and the cause of devastating disease in immunocompromised individuals and in those infected congenitally. Toxoplasma is considered a neglected parasitic disease of the United States by the Center for Disease Control and there is a dire need for new and effective therapeutics. Critical to the discovery of new drug targets is the characterization of events and proteins that are essential and unique to the parasite. Events required for Toxoplasma survival such as invasion and egress are regulated by calcium signaling processes that include proteins unique to the parasite. Interestingly, Toxoplasma egress depends on calcium signaling in both the parasite and host cell. How calcium fluxes and signaling within the parasite relate and translate to those occurring in the host and vice versa is not understood. While inside its host cell Toxoplasma divides within a specialized parasitophorous vacuole (PV) that protects it from cellular clearance mechanisms and provides it with the required nutrition. We hypothesize that, given its position at the interface between parasite and host, the PV also plays a critical role in integrating the signaling events that control egress and other calcium dependent events. To test this hypothesis we are combining a gene candidate approach with a novel screen for PV signaling proteins. Using a bioinformatics approach we have identified two secreted proteins that contain EF hand domains, which are found in numerous calcium signaling proteins including calmodulin and the parasite specific calcium dependent protein kinases. Interestingly, both of these proteins localize to the PV. Our first aim consists of determining the function of these two putative calcium-binding proteins during the lytic cycle of the parasite. Our second aim will be to identify and characterize signaling proteins associated with the PV. The full complement of PV proteins is far from known given significant challenges in separating its content from that of the parasite and host cell. Our novel approach to determine the protein makeup of the PV will be to identify proteins that interact or are near known vacuolar proteins using the proximity based BioID protein-protein interaction trap. Once we have identified putative novel PV proteins we will characterize six of them focusing on those likely to be involved in signaling events. In conjunction, our results will shed light on how host and parasite signaling pathways are integrated and exploit the essential roles of the PV and egress to discover new drug targets for this important and neglected parasite.

 描述（由申请人提供）：弓形虫是一种专性细胞内寄生虫，已知可慢性感染三分之一的人口，是免疫功能低下个体和先天感染者中导致毁灭性疾病的原因，弓形虫被认为是美国被忽视的寄生虫病。疾病控制中心指出，迫切需要新的有效疗法，发现新药物靶点的关键是对事件和蛋白质的表征。弓形虫生存所需的事件（例如入侵和流出）受到钙信号传导过程的调节，其中包括寄生虫所必需的蛋白质，弓形虫的流出取决于寄生虫和宿主细胞中的钙信号传导以及寄生虫内的钙传导和信号传导的方式。弓形虫在宿主细胞内分裂时会在一个特殊的寄生液泡（PV）内进行分裂，以保护其免受细胞清除。我们渴望，鉴于其在寄生虫和宿主之间的界面的位置，PV 在整合控制出口和其他钙依赖性事件的信号事件方面也发挥着关键作用。正在将候选基因方法与 PV 信号蛋白的新型筛选相结合，利用生物信息学方法，我们鉴定了两种含有 EF 手结构域的分泌蛋白，它们存在于多种钙信号蛋白中，包括钙调蛋白和寄生虫特异性钙依赖性蛋白激酶。这两个我们的首要目标是确定这两种假定的钙结合蛋白在寄生虫裂解周期中的功能。 考虑到从寄生虫和宿主细胞中分离 PV 蛋白的内容存在重大挑战，我们确定 PV 蛋白组成的新方法是鉴定和表征与 PV 相关的信号蛋白。使用基于接近性的 BioID 蛋白质-蛋白质相互作用陷阱识别相互作用或接近已知液泡蛋白质的蛋白质 一旦我们确定了假定的新型 PV 蛋白质，我们将重点关注那些可能参与信号传导事件的蛋白质。结果将揭示主机和寄生虫信号通路被整合，并利用 PV 和出口的重要作用来发现这种重要但被忽视的寄生虫的新药物靶点。