The role of lysine methylation in regulating the motility of Toxoplasma gondii

赖氨酸甲基化在调节弓形虫运动中的作用

• 批准号: 8437959
• 负责人: Ke Hu
• 金额: $ 39.51万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8437959
• 关键词: ATP Hydrolysis; Acquired Immunodeficiency Syndrome; Acute; Adverse effects; Affect; Apical; Binding Proteins; Biological Assay; Cell Nucleus; Cells; Chromatin; Complex; Cytoplasm; Defect; Development; Disease; Drug Targeting; Drug resistance; Encephalitis; Environment; Fetus; Gene Expression; Gene Targeting; Genetic Transcription; Goals; Growth; Histone-Lysine N-Methyltransferase; Histones; Human; Imaging technology; Immune system; In Vitro; Infection; Lysine; Lytic Phase; Mediating; Methylation; Methyltransferase; Motor; Motor Activity; Myosin ATPase; Nature; Parasites; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Physiology; Population; Proteins; Proteomics; Regulation; Role; Shotguns; Signal Transduction; Signal Transduction Pathway; Site; Testing; Time; Tissues; Toxoplasma gondii; Toxoplasmosis; Transcriptional Regulation; Translations; base; cell motility; comparative; design; in vivo; insight; killings; novel; prevent; protein distribution; public health relevance; single molecule

DESCRIPTION (provided by applicant): Toxoplasmosis is caused by the parasite Toxoplasma gondii. The infection of T. gondii can cause severe tissue damages when the immune system is compromised (such as in AIDS patients) or underdeveloped (such as in fetuses). If not treated in time, uncontrolled T. gondii proliferation (i.e. acute toxoplasmosis) will have devastating consequences, including the development of toxoplasmic encephalitis. Current medications for treating toxoplasmosis drugs block growth but do not kill the parasite; thus they must be taken for long periods, during which severe side-effects routinely develop. For infection with drug resistant parasite strains, the treatment options either are very limited or do not exist. New drug that target parasites more specifically are therefore desperately needed. To cause disease, T. gondii must reiterate its lytic cycle through host cell invasion, replication, and parasite egress. The successful completion of this cycle requires that the parasite sense changes in environmental conditions and switch between non-motile and motile states, accordingly. Despite its importance in parasite physiology, the signal relay that regulates this switch is poorly understood. Recently we discovered a previously unknown mechanism of regulating cell motility in T. gondii, mediated by a novel protein lysine methyltransferase, AKMT (for Apical complex lysine (K) methyltransferase). When AKMT is absent, the parasite remains immotile. Both invasion and egress, and thus the complete lytic cycle, are inhibited. If we understood the detailed nature of this inhibition, then it could be exploited to develop new parasite specific drugs. Towards that goal, three major questions need to be answered. 1) Is the motor itself crippled in the absence of AKMT? 2) Whether or not the motor is crippled, are other essential components of the motility apparatus dependent on methylation? 3) Why, in functional terms, is methylation required for each sensitive component (i.e., required for proper assembly of the apparatus?; for ATP hydrolysis or other catalytic activity?; for correct subcellular localization?) To answer these critical questions, we have designed the following three specific aims: Aim1-Determine if AKMT directly regulates the activity of the myosin motor complex; Aim2- Identify AKMT targets; and Aim3- Determine the function and spatial-temporal distribution of the AKMT targets. We will use a multi-faceted approach to pursue our aims, combining proteomics, state of the art imaging technologies, biophysical assays and targeted gene disruption.

描述（由申请人提供）：弓形虫病是由寄生虫弓形虫引起的。当免疫系统受到损害（例如在艾滋病患者中）或欠发达（例如胎儿中）时，弓形虫的感染可能会造成严重的组织损害。如果未及时治疗，则不受控制的gondii增殖（即急性弓形虫病）将带来毁灭性的后果，包括弓形虫性脑炎的发展。目前治疗毒性药物的药物阻止了生长，但不会杀死寄生虫。因此，必须长时间服用它们，在此期间，严重的副作用通常会发展出来。对于耐药寄生虫菌株感染，治疗选择要么非常有限或不存在。因此，迫切需要更具体地靶向寄生虫的新药。为了引起疾病，弓形虫必须通过宿主细胞侵袭，复制和寄生虫出口来重申其裂解周期。 因此，该周期的成功完成要求寄生虫的感觉在环境条件上的变化以及非运动状态和动向状态之间的切换。尽管它在寄生虫生理学中的重要性，但调节此转换的信号继电器对此开关的理解很少。最近，我们发现了一种以前未知的机制，该机制是通过一种新型蛋白质赖氨酸甲基转移酶AKMT（用于顶端复合物赖氨酸（K）甲基转移酶）介导的gondii中细胞运动的机制。当不存在AKMT时，寄生虫保持不变。入侵和出口，因此均受到抑制。如果我们了解这种抑制的详细性质，则可以利用它来开发新的寄生虫药物。为了实现这一目标，需要回答三个主要问题。 1）在没有AKMT的情况下，电动机本身是否瘫痪？ 2）电动机是否瘫痪，运动设备的其他必要组成部分是否取决于甲基化？ 3）为什么用功能性术语来说，每个敏感成分需要甲基化（即适当组装设备需要？；用于ATP水解或其他催化活性？用于正确的亚细胞定位？ AIM2-确定AKMT目标； AIM3-确定AKMT目标的功能和时空分布。我们将使用多方面的方法来追求我们的目标，结合蛋白质组学，最先进的成像技术，生物物理测定和靶向基因破坏。