Stress Induced Control of Protein Translation in Entamoeba Histolytica

应激诱导的溶组织内阿米巴蛋白质翻译控制

• 批准号: 8664552
• 负责人: LESLY A TEMESVARI
• 金额: $ 7.36万
• 依托单位: CLEMSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8664552
• 关键词: Amebic Liver Abscess; Amebic colitis; Apoptosis; Bioterrorism; Cardiovascular system; Categories; Cells; Collaborations; Contracts; Cyst; Data; Developing Countries; Dictyostelium discoideum; Dominant-Negative Mutation; Entamoeba histolytica; Environment; Epithelial; Eukaryota; Eukaryotic Initiation Factor-2; Food; Gene Expression; Genome; Goals; Growth; Health; Immune response; Indiana; Infection; Ingestion; Intestines; Invaded; Knowledge; Large Intestine; Leishmania; Liver Abscess; Liver Circulation; Mammalian Cell; Measures; Morbidity - disease rate; Parasites; Parasitic infection; Phosphorylation; Phosphotransferases; Plasmodium; Play; Polyribosomes; Probability; Process; Protein Biosynthesis; Proteins; RNA, Transfer, Met; Regulation; Reproduction spores; Resources; Ribosomes; Role; Route; Serum; Small Intestines; Starvation; Stress; Structure; System; Testing; Toxoplasma gondii; Transgenic Organisms; Translation Initiation; Translations; Universities; Water; Yeasts; attributable mortality; base; biological adaptation to stress; excystation; fitness; medical schools; meetings; mutant; pathogen; pressure; protein complex; response; success

DESCRIPTION (provided by applicant): Entamoeba histolytica is the causative agent of amoebic dysentery and is classified as a Category B bioterrorism agent. E. histolytica infections are contracted by ingestion of latent cysts from fecally contaminated food or water. Amoeboid trophozoites emerge in the small intestine and subsequently move to the large bowel. The parasite may also cross the gut epithelial layer and establish extra-intestinal infections, the mos common of which is amoebic liver abscess. During the course of infection in the host, E. histolytica likely confronts stress brought on by ever-changing environments (e.g., small intestine, large intestine, circulation, liver) and by the host immune response. To survive, the parasite must circumvent these exogenous pressures. Thus, it may be useful to target E. histolytica's response to stress for therapy. In other parasites, stress can activate eIF2α kinases that phosphorylate the α-subunit of eukaryotic initiation factor-2 (eIF2α). eIF2α is part of a protein complex that delivers Met-tRNA to ribosomes for translation initiation. Phosphorylation of eIF2α inhibits this activity which, in turn, leads to a decline in protein synthesis. This allows clls to conserve resources and reconfigure gene expression to effectively manage stress. Genome analyses indicate that E. histolytica possesses all of the components of this stress response system; however, the premise that phospho-eIF2α controls stress and translation in this pathogen has not been tested. This represents a profound gap in knowledge. Thus, the goal of this application is to characterize this stress response system in E. histolytica. The first aim isto define the functions of phospho-eIF2α and to authenticate eIF2α kinases as they relate to the E. histolytica stress response. This will involve tracking phospho-eIF2α during a variety of stressful conditions. Furthermore, cells expressing dominant negative eIF2α will be subjected to stress and their viability will be measured. The second aim is to determine if translational control plays a role in the E. histolytica stress response. To answer this question, cells will be subjected to stress and the abundance of polyribosomes will be quantified. Preliminary data demonstrate that at least one condition of stress, serum-starvation, can induce phosphorylation of eIF2α in E. histolytica. Thus, there is high probability of success in defining a role for phospho-eIF2α in control of translation in E. histolytica. If inhibition of translation accompanies stress, it would represent the first example of translational control in this pathogen.

描述（由申请人提供）：溶组织内阿米巴是阿米巴痢疾的病原体，被归类为 B 类生物恐怖制剂。溶组织内阿米巴感染是通过摄入来自粪便污染的食物或水中的阿米巴滋养体而感染的。寄生虫也可能穿过肠上皮层并定居。肠外感染，其中最常见的是阿米巴肝脓肿在宿主感染过程中，溶组织阿米巴可能面临不断变化的环境（例如小肠、大肠、循环、肝脏）带来的压力。为了生存，寄生虫必须规避这些外源压力。因此，针对其他寄生虫的应激反应可能会有所帮助。压力可以激活 eIF2α 激酶 磷酸化真核起始因子 2 (eIF2α) 的 α 亚基是蛋白质复合物的一部分，该蛋白质复合物将 Met-tRNA 传递至核糖体以进行翻译起始，eIF2α 的磷酸化会抑制这种活性，从而导致翻译能力下降。这使得细胞能够节省资源并重新配置基因表达以有效地管理应激。基因组分析表明，溶组织内阿米巴拥有所有的成分。这种应激反应系统；然而，磷酸化 eIF2α 控制这种病原体的应激和翻译的前提尚未得到测试，这代表了巨大的知识空白，因此，本申请的目标是表征大肠杆菌中的这种应激反应系统。第一个目标是定义磷酸化 eIF2α 的功能并验证与溶组织内阿米巴应激反应相关的 eIF2α 激酶，这将涉及在各种应激期间追踪磷酸化 eIF2α。 此外，表达显性失活 eIF2α 的细胞将受到压力，并测量它们的活力，以确定翻译控制是否发挥作用。 为了回答这个问题，细胞将受到应激，并且对多聚核糖体的丰度进行定量，初步数据表明，至少一种应激条件（血清饥饿）可以诱导 eIF2α 磷酸化。因此，确定磷酸化 eIF2α 在溶组织内阿米巴中控制翻译的作用的可能性很高。伴随着压力，它会 代表了该病原体翻译控制的第一个例子。