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（由申请方提供）：溶组织内阿米巴是阿米巴痢疾的病原体，被归类为B类生物恐怖剂。E.溶组织菌感染是通过从粪便污染的食物或水中摄取潜伏的包囊而感染的。阿米巴滋养体出现在小肠，随后移动到大肠。寄生虫也可以穿过肠道上皮层并建立肠外感染，其中最常见的是阿米巴肝脓肿。在感染宿主的过程中，E.溶组织菌可能面临由不断变化的环境带来的压力（例如，小肠、大肠、循环、肝脏）和宿主免疫应答。为了生存，寄生虫必须避开这些外部压力。因此，靶向E.溶组织菌对压力的反应在其他寄生虫中，应激可激活eIF 2 α激酶 磷酸化真核起始因子2 α亚基的蛋白。eIF 2 α是蛋白复合物的一部分，可将Met-tRNA递送至核糖体以启动翻译。eIF 2 α的磷酸化抑制这种活性，这反过来又导致蛋白质合成的下降。这使得cll能够保存资源并重新配置基因表达以有效地管理压力。基因组分析表明，E. histolytica具有该应激反应系统的所有组分;然而，磷酸化eIF 2 α控制该病原体中的应激和翻译的前提尚未得到验证。这是一个深刻的知识差距。因此，本申请的目标是表征E.溶组织剂本研究的第一个目的是确定磷酸化eIF 2 α的功能，并验证eIF 2 α激酶与大肠杆菌的关系。溶组织应激反应这将涉及在各种压力下跟踪磷酸化eIF 2 α， 条件此外，将对表达显性阴性eIF 2 α的细胞进行强制降解，并测定其活力。第二个目标是确定翻译控制是否起作用 在E.溶组织应激反应为了回答这个问题，细胞将受到压力，多聚核糖体的丰度将被量化。初步数据表明，至少有一种应激条件，血清饥饿，可以诱导eIF 2 α的磷酸化。溶组织剂因此，成功确定磷酸化eIF 2 α在控制大肠杆菌翻译中的作用的可能性很高。溶组织剂如果翻译抑制伴随着压力， 代表了这种病原体中第一个翻译控制的例子。