Dissecting the roles of protein O-GlcNAcylation in Toxoplasma gondii

剖析蛋白 O-GlcNAc 酰化在弓形虫中的作用

• 批准号: 8512340
• 负责人: Kami Kim
• 金额: $ 23.55万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-12 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8512340
• 关键词: Acetylglucosamine; Acquired Immunodeficiency Syndrome; Affect; Apicomplexa; Biochemical; Biological Process; Chemistry; Congenital Abnormality; Development; Disease; Enzymes; Epigenetic Process; Eukaryota; Gene Expression Regulation; Genes; Genetic Transcription; Glycoproteins; Human; Immune; Individual; Infection Control; Investigation; Life; Life Cycle Stages; Mediating; Mediator of activation protein; Metabolism; Nutrient; O-GlcNAc transferase; Organism; Parasites; Pathogenesis; Patients; Pregnancy; Process; Proteins; Role; Serine; Signal Transduction; Signaling Molecule; Site; Spontaneous abortion; Staging; Stress; System; Testing; Threonine; Toxoplasma gondii; Transcriptional Regulation; Validation; Woman; abortion; base; comparative; genetic regulatory protein; glycosylation; interest; obligate intracellular parasite; pathogen; prevent; protein transport; public health relevance; response

DESCRIPTION (provided by applicant): Toxoplasma gondii is an obligate intracellular parasite in the phylum Apicomplexa. This parasite causes life-threatening diseases in AIDS patients and immune-compromised individuals, and birth defects or abortions when women are infected during pregnancy. An essential process for pathogenesis and persistence of T. gondii in human hosts is the interconversion between the rapidly dividing tachyzoites and latent bradyzoites. Despite its pathological significance, the signaling molecules and the mechanisms underlying this process are poorly understood. Recently, ubiquitous O-GlcNAcylation and O-GlcNAc transferase (OGT), the enzyme that catalyzes this process, have been identified in T. gondii. OGT adds a single ¿-N-acetylglucosamine to serine or threonine residues of intracellular proteins. Because in mammalian organisms, O-GlcNAc is a mediator of intracellular signaling, transcription regulation, and protein trafficking in response to cellular nutrients or stress, we hypothesize that O-GlcNAc may serve as an active player in T. gondii's life cycle transition between tachyzoites and bradyzoites by dynamically modifying intracellular proteins. To test this hypothesis, we will use a chemoenzymatic approach to identify O-GlcNAc-modified proteins in T. gondii tachyzoites (Aim 1). Next, we will apply this approach for comparative analysis of changes in protein O-GlcNAc status in T. gondii tachyzoite-bradyzoites transition. We will focus our studies on gene-regulatory proteins that are involved in this process. Once identified, we will characterize the role of O-GlcNAc in mediating the biological functions of these modified proteins in this life-cycle transition (Aim 2). Finally, we will characterize how changes in global protein O-GlcNAcylation mediated by OGT influence the life-cycle transition of T. gondii (Aim 3).

描述（由申请人提供）：弓形虫是顶复门中的一种专性细胞内寄生虫，这种寄生虫会导致艾滋病患者和免疫功能低下的个体患上危及生命的疾病，并且当妇女在怀孕期间感染时会导致出生缺陷或流产。弓形虫在人类宿主中的发病机制和持久性是快速分裂的速殖子和潜伏的缓殖子之间的相互转化，尽管其具有病理意义，但最近，人们对弓形虫中普遍存在的 O-GlcNAc 基化和 O-GlcNAc 转移酶 (OGT)（催化这一过程的酶）了解甚少。 -N-乙酰氨基葡萄糖到细胞内蛋白质的丝氨酸或苏氨酸残基，因为在哺乳动物生物体中，O-GlcNAc 是响应细胞营养或应激的细胞内信号传导、转录调节和蛋白质运输的介质，因此我们认为 O-GlcNAc 可能发挥作用。作为弓形虫生命周期在速殖子和缓殖子之间转变的活跃参与者，通过动态修饰细胞内蛋白质来检验这一假设，我们将使用化学酶法鉴定弓形虫速殖子中 O-GlcNAc 修饰的比较蛋白（目标 1） 接下来，我们将应用这种方法来分析弓形虫速殖子-缓殖子转变中蛋白质 O-GlcNAc 状态的变化。我们对参与这一过程的基因调节蛋白的研究一旦确定，我们将进行研究。 描述 O-GlcNAc 在介导这些修饰蛋白在此生命周期转变中的生物学功能中的作用（目标 2）。 OGT 介导的蛋白质 O-GlcNAc 酰化影响弓形虫的生命周期转变（目标 3）。