Protist Oxygen Sensing in Human Disease Protist Oxygen Sensing in Human Disease

人类疾病中的原生生物氧传感人类疾病中的原生生物氧传感

基本信息

批准号：
10467358
负责人：
Ira J Blader
金额：
$ 64.82万
依托单位：
STATE UNIVERSITY OF NEW YORK AT BUFFALO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10467358
关键词：
Address Aerobic American Amino Acids Binding Proteins Biochemical Biological Assay Blood Brain CUL1 gene Calcium Cell Survival Cell physiology Cells Characteristics Complex Cues Cyst Data Development Dictyostelium Differentiation and Growth Disease Distant Environment Essential Amino Acids Exposure to F-Box Proteins Face Fetus Goals Growth Heart Homeostasis Hydroxylation Hypoxia Hypoxia Inducible Factor Immune response Immunocompromised Host In Vitro Infection Interferon Type II Knowledge Learning Life Ligase Lung Mediating Medical Metabolic Modification Muscle Names Nutrient Organism Oxygen Parasites Pathway interactions Peptide Elongation Factor 2 Phosphorylation Phosphotransferases Polyubiquitin Procollagen-Proline Dioxygenase Proliferating Proline Protein Biosynthesis Proteins Proteome Publishing RBX1 gene Resistance Retina Shapes Stream Stress Testing Tissues Toxoplasma Toxoplasma gondii Ubiquitin Ubiquitination Virulence Work base cytokine extracellular genome analysis human disease in vivo mutant new therapeutic target novel therapeutics pathogen phyA phytochrome phyB phytochrome recruit response transcription factor ubiquitin ligase ubiquitin-protein ligase

项目摘要

Sensing and responding to changes in environmental oxygen is critical for aerobic organisms. Metazoans accomplish this by destabilizing a transcription factor called hypoxia inducible factor (HIF) in oxygen sufficiency. This is achieved by an oxygen-dependent prolyl 4-hydroxylase (PHD) that hydroxylates proline residues in the HIF-1α transcription factor that targets it for ubiquitin-dependent proteasomal degradation. Protozoans have PHDs but lack HIF and thus respond to changes in oxygen differently and we use the evolutionary distant protists Dictyostelium and Toxoplasma to address this question. Initial studies in Dictyostelium revealed that its PHD, DdPHYa, modifies a proline in Skp1, which is a component of the Skp1/Cullin1/F-box protein/Rbx1 polyubiquitin ligase complex. Skp1 prolyl hydroxylation does not affect its stability, but allows it to be modified by a pentasaccharide that acts to alter the repertoire of associated F- Box proteins. Genome analysis and biochemical assays demonstrated that this Skp1 modification pathway is conserved in the protozoan parasite Toxoplasma, but not in metazoans. Loss of Toxoplasma PHYa leads decreases virulence in vivo and decreased growth in vitro under limited O2 and amino acid conditions. Unlike Dictyostelium, Toxoplasma expresses a second PHD, PHYb, which is required for colonization of oxygen rich tissues as well as Toxoplasma growth at high oxygen. In contrast to PHYa, PHYb functions by regulating elongation during protein synthesis and specifically does so at elevated O2 levels. Because of its medical importance, we will focus on Toxoplasma and pursue three specific aims: i) Determine how PHYa mediates growth at low oxygen and amino acids; ii) Define how PHYb regulates elongation; and iii) Test whether PHYa and PHYb work in tandem as an oxygen-sensing rheostat to grow in whatever oxygen tension in encounters as it infects a host and causes disease.

感知和响应环境氧气的变化对于需氧生物通过破坏转录的稳定性来实现这一点。这是通过称为缺氧诱导因子（HIF）的氧气充足性来实现的。通过氧依赖性脯氨酰 4-羟化酶 (PHD) 羟化脯氨酸 HIF-1α 转录因子中的残基，以泛素依赖性为目标原生动物具有 PHD，但缺乏 HIF，因此有反应。以不同的方式改变氧气，我们使用进化遥远的原生生物盘基网柄菌和弓形虫的初步研究解决了这个问题。盘基网柄菌属揭示其 PHD DdPHYa 修饰了 Skp1 中的脯氨酸，该脯氨酸是 Skp1/Cullin1/F-box 蛋白/Rbx1 多聚泛素连接酶的组成部分 Skp1 脯氨酰羟基化不会影响其稳定性，但允许其稳定性。由五糖修饰，五糖可改变相关的 F- 基因组分析和生化分析证明了这一点。 Skp1 修饰途径在原生动物寄生虫弓形虫中是保守的，但在后生动物中则不然，弓形虫 PHYa 的缺失会导致毒力降低。在有限的氧气和氨基酸条件下，体内和体外生长均下降。与盘基网柄菌不同，弓形虫表达第二种 PHD，PHYb，它是富氧组织定植以及弓形虫生长所需的与 PHYa 不同，PHYb 通过调节伸长发挥作用。在蛋白质合成过程中，特别是在氧气水平升高的情况下。鉴于其医学重要性，我们将重点关注弓形虫并追求三个特定目标目标： i) 确定 PHYa 如何在低氧和氨基酸条件下介导生长； ii) 定义 PHYb 如何调节伸长；以及 iii) 测试 PHYa 和 PHYb 是否作为氧传感变阻器协同工作，可在任何氧气中生长当它感染宿主并引起疾病时，会产生紧张感。