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 类生物恐怖主义制剂。溶组织内阿米巴感染是通过摄入粪便污染的食物或水中的潜伏包囊而感染的。变形虫滋养体出现在小肠中，随后移动到大肠。寄生虫还可能穿过肠道上皮层并引起肠外感染，其中最常见的是阿米巴肝脓肿。在宿主感染过程中，溶组织内阿米巴可能面临不断变化的环境（例如小肠、大肠、循环、肝脏）和宿主免疫反应带来的压力。为了生存，寄生虫必须规避这些外源压力。因此，针对溶组织内阿米巴对应激的反应进行治疗可能有用。在其他寄生虫中，压力可以激活 eIF2α 激酶 磷酸化真核起始因子 2 (eIF2α) 的 α 亚基。 eIF2α 是蛋白质复合物的一部分，可将 Met-tRNA 传递至核糖体以启动翻译。 eIF2α 的磷酸化会抑制这种活性，进而导致蛋白质合成下降。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压力。基因组分析表明，溶组织内阿米巴拥有该应激反应系统的所有组成部分；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。这代表了知识上的巨大差距。因此，本申请的目标是表征溶组织内阿米巴的应激反应系统。第一个目标是定义磷酸化 eIF2α 的功能并验证 eIF2α 激酶，因为它们与溶组织内阿米巴应激反应相关。这将涉及在各种压力期间跟踪磷酸化 eIF2α 状况。此外，表达显性失活 eIF2α 的细胞将受到应激，并测量其活力。第二个目标是确定平移控制是否发挥作用 在溶组织内阿米巴应激反应中发挥作用。为了回答这个问题，细胞将受到压力，并且多聚核糖体的丰度将被量化。初步数据表明，至少一种应激条件（血清饥饿）可以诱导溶组织阿米巴中 eIF2α 的磷酸化。因此，确定磷酸化 eIF2α 在溶组织内阿米巴翻译控制中的作用很有可能成功。如果翻译抑制伴随着压力，就会 代表了该病原体翻译控制的第一个例子。