Nutrient Regulation of Cell Physiology by O-GlcNAcylation

O-GlcNAc 酰化对细胞生理学的营养调节

基本信息

批准号：
9754184
负责人：
GERALD Warren HART
金额：
$ 28.88万
依托单位：
UNIVERSITY OF GEORGIA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-08-10 至 2020-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9754184
关键词：
Affect Affinity Aging Alzheimer&apos s Disease Binding Cardiovascular Diseases Catalytic Domain Cell Cycle Cell Nucleus Cell physiology Cells Chromatin Chronic Disease Complex Cytoplasm Cytoplasmic Protein DNA DNA Binding DNA Methylation DNA Modification Methylases DNA-Binding Proteins DNA-Directed RNA Polymerase Data Diabetes Mellitus Disease Eating Enzymes Epigenetic Process Etiology Gene Expression Genes Genetic Transcription Glucose Goals Heat-Shock Response Histones Holoenzymes Human Kinetics Length Life Lymphocyte Activation Malignant Neoplasms Mammals Mediating Methods Mitochondrial Proteins Modification Molecular Nerve Degeneration Nuclear Protein Nuclear Proteins Nutrient O-GlcNAc transferase Paper Peptides Phosphorylation Phosphotransferases Plants Play Post-Translational Protein Processing Property Protein Microchips Proteins Proteomics RNA Polymerase II Regulation Role Signal Transduction Site Specificity Stimulus Stress Substrate Specificity TAF1 gene TATA-Box Binding Protein Therapeutic Toxic effect Transcriptional Regulation Work blood glucose regulation circadian pacemaker in vivo insight knock-down mutant overexpression promoter protein B protein aminoacid sequence response sensor stoichiometry sugar therapeutic development trafficking transcription factor transcription factor S-II

项目摘要

The cycling of N-acetylglucosamine on Ser(Thr) residues (O-GlcNAcylation) of nuclear, cytoplasmic and mitochondrial proteins serves as a nutrient sensor to regulate signaling, transcription, and cellular physiology. Abnormal O-GlcNAcylation underlies the etiology of diabetes, cancer and Alzheimer's disease. O-GlcNAcylation regulates nearly every aspect of transcription, including RNA polymerase II, histones, DNA methyltransferases, and nearly all transcription factors. Yet we know very little about the mechanisms involved. TATA-binding protein (TBP) is amongst the most important components of the transcription machinery. Our recent studies indicate that TBP regulated by O-GlcNAcylation in response to nutrients. O-GlcNAcylation has extensive crosstalk with protein phosphorylation and other modifications. However, unlike phosphorylation, which is catalyzed by hundreds of kinases, there is only one highly conserved gene encoding O-GlcNAc transferase (OGT). Nonetheless, OGT site-specifically modifies thousands of proteins. Our data indicate that OGT's substrate specificity is not only determined by its specificity for peptide sequence, but also by its transient associations with other proteins, which dynamically target it to specific substrates. OGT targeting interactions are largely mediated by its tetratricopeptide repeats (TPRs). OGT missing TPRs remains active against small peptides, but has poor activity against full-length proteins. Herein we will investigate two major questions related to O-GlcNAcylation: Specific Aim 1: Continue to Study Glucose Regulation of TATA-binding protein (TBP) via its O-GlcNAcylation. Hypothesis: At certain promoters, glucose regulates TBP DNA-binding and its ability to bend DNA by altering its O- GlcNAcylation. We will systematically elucidate mechanisms and functions of this nutrient regulation of TBP. Three goals: A. Roles of O-GlcNAcylation in the molecular and cellular properties of TBP? B. Roles of O- GlcNAc in TBP's Interactions in the Transcription Cycle. C. O-GlcNAc's In Vivo Roles in TBP-mediated Gene Expression. Specific Aim 2: Continue to Elucidate How OGT is Specifically Targeted to Thousands of Different Protein Substrates? Hypothesis: OGT achieves a high degree of specificity not only by its recognition of peptide sequence, but also by it being targeted to substrates by accessory proteins. This Aim will systematically evaluate both the general and specific roles of OGT binding partners in OGT's activities toward its many substrates. Given O-GlcNAc's importance to mechanisms of chronic disease, such as glucose toxicity in diabetes, cancer and neurodegeneration, elucidation of these mechanisms will not only be key to understanding transcription and signaling, also to uncovering new avenues for therapeutics.

N-乙酰氨基葡萄糖在细胞核、细胞质和细胞核的 Ser(Thr) 残基上的循环（O-GlcNAcylation）线粒体蛋白作为营养传感器来调节信号传导、转录和细胞生理。异常的 O-GlcNAc 酰化是糖尿病、癌症和阿尔茨海默氏病的病因学基础。 O-GlcNAc 酰化几乎调节转录的各个方面，包括 RNA 聚合酶 II、组蛋白、DNA 甲基转移酶和几乎所有转录因子。然而我们对其机制知之甚少涉及。 TATA 结合蛋白 (TBP) 是转录最重要的成分之一机械。我们最近的研究表明，TBP 受 O-GlcNAc 酰化调节以响应营养物质。 O-GlcNAc 酰化与蛋白质磷酸化和其他修饰有广泛的串扰。然而，与由数百种激酶催化的磷酸化不同，只有一个高度保守的基因编码 O-GlcNAc 转移酶 (OGT)。尽管如此，OGT 仍可对数千种蛋白质进行位点特异性修饰。我们的数据表明OGT的底物特异性不仅取决于其对肽的特异性序列，而且还通过其与其他蛋白质的短暂关联，动态地将其靶向特定的基材。 OGT 靶向相互作用主要由其四肽重复序列 (TPR) 介导。奥格特缺失的 TPR 对小肽仍具有活性，但对全长蛋白质的活性较差。在此，我们将研究与 O-GlcNAcylation 相关的两个主要问题：具体目标 1：继续研究 TATA 结合蛋白 (TBP) 通过 O-GlcNAc 酰化的葡萄糖调节。假设：在在某些启动子中，葡萄糖调节 TBP DNA 结合及其通过改变 O- 来弯曲 DNA 的能力 GlcNAc酰化。我们将系统地阐明TBP的这种营养调节机制和功能。三个目标： A. O-GlcNAc 酰化在 TBP 的分子和细胞特性中的作用？ B. O-的角色 TBP 在转录周期中的相互作用中的 GlcNAc。 C. O-GlcNAc 在 TBP 介导中的体内作用基因表达。具体目标 2：继续阐明 OGT 如何具体针对数千种不同的蛋白质底物？假设：OGT 实现高度特异性而不是不仅通过其识别肽序列，还通过其通过辅助物靶向底物蛋白质。该目标将系统地评估 OGT 结合伙伴的一般和特定作用 OGT 针对多种底物的活动。鉴于 O-GlcNAc 对慢性疾病机制的重要性，例如糖尿病中的葡萄糖毒性，癌症和神经退行性疾病，阐明这些机制不仅是理解的关键转录和信号转导，也揭示了治疗的新途径。