Mechanism of cytotoxicity of ricin

蓖麻毒素的细胞毒性机制

基本信息

批准号：
7846483
负责人：
NILGUN E TUMER
金额：
$ 5.38万
依托单位：
RUTGERS, THE STATE UNIV OF N.J.
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-05 至 2011-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7846483
关键词：
Address Adenine Aerosols Affect Antidotes Apoptosis Apoptotic Binding Biochemical Biological Models Biological Warfare Bioterrorism Breathing Categories Cell Death Cells Cessation of life Cytosol Defect Depurination Development Endocytosis Endoplasmic Reticulum Enterotoxins Genes Genomics Induction of Apoptosis Intoxication Lectin Lung MAPK14 gene MAPK8 gene Mammalian Cell Measures Medical Membrane Messenger RNA Molecular Mutagenesis N glycosidase National Institute of Allergy and Infectious Disease Plants Plasmids Process Protein Biosynthesis Protein Synthesis Inhibition Proteins RNA Splicing Resistance Respiratory System Respiratory tract structure Ribosomal RNA Ribosomes Ricin Ricinus communis Role Signal Pathway Signal Transduction Small Interfering RNA System Techniques Terrorism Toxin Translations Vaccines Yeasts base biodefense cell injury cell killing cytotoxicity design genome-wide high risk instrument mutant novel therapeutics prevent prototype response ribosomal A-protein

项目摘要

DESCRIPTION (provided by applicant): Ribosome inactivating proteins (RIPs) have been used as instruments of biological warfare and terrorism. Ricin is a heterodimeric plant toxin that consists of A and B-chains and the prototype of type II RIPs. Its B- chain is a lectin that enables cell binding. After endocytosis, the A-chain translocates through the endoplasmic reticulum membrane to reach the cytosol where its N-glycosidase activity removes a specific adenine from the highly conserved, sarcin/ricin loop (SRL) in the large rRNA. Ricin has been classified as Category B priority for biodefense. Very little is known about the membrane translocation and ribosome interactions of ricin and the molecular mechanism by which it causes apoptosis in mammalian cells. We have established yeast as a biologically relevant model system to study the activity of RTA, and isolated mutant forms of RTA, which do not kill cells. Translation inhibition by ribosome depurination has been hypothesized to be responsible for the cytotoxicity of ricin. However, our preliminary analysis of the nontoxic RTA mutants indicates that ribosome depurination is not sufficient for cytotoxicity. This project aims to use yeast and mammalian cells as complementary systems to understand the molecular basis for ricin intoxication. Specific Aims: 1. Using the nontoxic RTA mutants, determine if ribosome binding and depurination are required for cytotoxicity in yeast and induction of apoptosis in mammalian cells. 2. Characterize the interaction between RTA and ribosomal protein PO and determine if binding to PO is essential for ribosome depurination by RTA. 3. Identify the cellular genes necessary for cytotoxicity of RTA in yeast and determine if RTA causes cell death by affecting induction of the unfolded protein response (UPR). Ricin is not only a bioterrorism threat, but inhibits translation by a similar mechanism as the bacterial enterotoxins. Therefore, the studies outlined in this application will have important implications for the design of protection strategies against AB-toxins that are classified as high-risk candidates for bioterrorism.

描述（由申请人提供）：核糖体灭活蛋白（RIP）已被用作生物战和恐怖主义的工具。 Ricin是一种异二聚体植物毒素，由A和B链和II型撕裂的原型组成。它的B链是一种凝集蛋白，可实现细胞结合。内吞作用后，A链通过内质网膜易位，到达其N-糖苷酶活性的细胞质，从而从高度保守的sarcin/ricin loop（SRL）中去除特定的腺嘌呤。 Ricin已被归类为Biodefense的B类优先级。关于ricin的膜易位和核糖体相互作用以及引起哺乳动物细胞凋亡的分子机制，知之甚少。我们已经建立了酵母作为生物学相关的模型系统，以研究RTA的活性和RTA的孤立突变形式，这些突变体形式不会杀死细胞。核糖体脱育的翻译抑制已被认为是ricin的细胞毒性的原因。但是，我们对无毒RTA突变体的初步分析表明，核糖体脱育不足以使其具有细胞毒性。该项目旨在将酵母和哺乳动物细胞用作互补系统，以了解里奇蛋白中毒的分子基础。具体目的：1。使用无毒的RTA突变体，确定酵母中细胞毒性和诱导哺乳动物细胞中凋亡的核糖体结合和脱纯。 2。表征RTA与核糖体蛋白PO之间的相互作用，并确定与PO的结合是否对于RTA的核糖体脱尿至关重要。 3。确定酵母中RTA细胞毒性所需的细胞基因，并通过影响展开的蛋白质反应（UPR）的诱导来确定RTA是否导致细胞死亡。 ricin不仅是一种生物恐怖主义威胁，而且通过与细菌肠毒素相似的机制抑制翻译。因此，本应用程序中概述的研究将对针对AB-Toxins的保护策略的设计具有重要意义，而AB毒素被归类为生物恐怖主义的高风险候选者。