Role of ROP GTPases in sulfate transceptor SULTR1;2-regulated sulfur nutrient sensing

ROP GTPases 在硫酸盐受体 SULTR1;2 调节的硫营养物传感中的作用

• 批准号: 10412405
• 负责人: ZHI-LIANG ZHENG
• 金额: $ 14.54万
• 依托单位: HERBERT H. LEHMAN COLLEGE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10412405
• 关键词: Alleles; Amino Acids; Arabidopsis; Binding; Biochemical; C-terminal; Cell Nucleus; Cell membrane; Cells; Code; Complex; Cytoplasm; Disease; Drug Targeting; Elements; Enhancers; Environment; Eukaryota; Event; FHL1 gene; Family; Gene Expression; Genes; Genetic; Genetic Transcription; Goals; Growth and Development function; Guanosine Triphosphate Phosphohydrolases; Human; Lead; Link; MAP Kinase Modules; Malignant Neoplasms; Measures; Mediating; Minerals; Modeling; Modification; Monomeric GTP-Binding Proteins; Nitrates; Nutrient; Organism; Pathologic; Pathway interactions; Pattern; Peptides; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Physiological; Plant Model; Plants; Polymerase; Post-Translational Protein Processing; Proteins; RNA Polymerase II; RNA polymerase II largest subunit; Regulatory Element; Reporting; Research; Role; Signal Transduction; Sulfate; Sulfur; System; Testing; Transcription Initiation; Transcriptional Regulation; Work; Yeasts; Zinc; activating transcription factor; base; detection of nutrient; drug development; gain of function; inorganic phosphate; insight; loss of function; member; mutant; novel; nutrition; plant fungi; promoter; protein degradation; protein function; public health relevance; receptor; recruit; response; rho; rho GTP-Binding Proteins; sensor; sulfate transporter; transcription factor; transcription factor TFIIH; uptake

ABSTRACT Many living organisms including humans have evolved mechanisms to sense and respond to levels of mineral nutrients or amino acids. In this application, we propose to use Arabidopsis plant sulfur (S) nutrient sensing and signaling as an experimental system to dissect transporting receptor-mediated nutrient sensing mechanisms. Our prior research has led to identification of sulfate transporter SULTR1;2 as a receptor. This type of dual-function transporting receptor, termed transceptor, has been increasingly found in eukaryotic organisms and is expected to increase nutrient use efficiency by performing both its sensing and transporting functions. However, how plants use the transceptor SULTR1;2 to transduce the S signal in the control of gene expression has remained a central unanswered question and becomes the focus of the present project. Our recent studies have revealed a conserved shortcut model of transcriptional control that links Rho family small GTPases to RNA polymerase II (Pol II) C-terminal domain (CTD) Ser phosphorylation across plants, fungi and humans. The Pol II CTD contains various number of conserved heptad peptide repeats (Y1S2P3T4S5P6S7) in which each amino acid can be subjected to different posttranslational modifications. Thus, the posttranslational modification pattern is complex and collectively called the CTD code. Among the CTD code, Ser2 and Ser5 phosphorylation along the gene is very important for initiating transcription and completing the transcription cycle. In the classical model of transcriptional control, upon activation by Rho or Ras GTPases, the MAP kinase cascade activates transcription factors that bind to gene-specific cis-elements and helps recruit Pol II to the core promoter. In contrast, in the shortcut model, Rho GTPase signaling directly targets the Pol II CTD Ser2 and Ser5 phosphorylation and thus can rapidly bring about large-scale gene expression changes. We now have preliminary evidence indicating that activity of ROP2 GTPase, which is a member of plant-unique ROP subfamily of Rho GTPases, and levels of CTD Ser2 and Ser5 phosphorylation are impacted by S status. In addition, ROP GTPase activity is higher in SULTR1;2 mutants. Therefore, we hypothesize that ROP2 and its functionally redundant ROP4 act as negative regulators in SULTR1;2-mediated S sensing and signaling. The proposed work aims to fill the major gaps from SULTR1;2 to Pol II transcription. Specifically, Aim 1 is to test that ROP2 and ROP4 GTPases act as negative regulators in SULTR1;2-mediated S sensing and signaling using genetic and biochemical approaches. Aim 2 is to test the hypothesis that ROP2-mediated Pol II shortcut model is required for S response. In Aim 3, we propose to test that ROP2-controlled SLIM1 transcription factor activity and ROP2-mediated Pol II CTD code modulation act cooperatively to achieve the most productive transcription of S-deficiency induced S-response genes. The proposed study will not only lead to novel mechanistic insights into how plants use nutrient transceptor SULTR1;2 and ROP signaling switch to efficiently control gene expression but also provide a paradigm for transcriptional regulation in other organisms.

抽象的 包括人类在内的许多活生物体已经发展了机制，以感知和响应矿物水平 营养或氨基酸。在此应用中，我们建议使用拟南芥植物硫的营养感应 以及作为实验系统的信号传导，以剖析运输受体介导的营养感应 机制。我们先前的研究导致硫酸盐转运蛋白Sultr1; 2作为受体。这 在真核生物中越来越多地发现了越来越多的双功能传输受体（称为置换器） 有机体，预计将通过执行感应和运输来提高营养的使用效率 功能。然而，植物如何使用透镜Sultr1; 2在控制基因中转导S信号 表达仍然是一个未解决的中心问题，并成为本项目的重点。我们的 最近的研究表明，保守的转录控制快捷方式模型将Rho家族小 跨植物，真菌和 人类。 Pol II CTD包含各种保守的七肽重复序列（Y1S2P3T4S5P6S7） 每种氨基酸可以进行不同的翻译后修饰。因此，翻译后 修改模式是复杂的，统称为CTD代码。在CTD代码中，SER2和SER5 沿基因的磷酸化对于启动转录和完成转录非常重要 循环。在转录控制的经典模型中，在通过Rho或Ras GTPase激活后，地图 激酶级联激活与基因特异性顺算元元素结合的转录因子，并有助于募集POL II 核心启动子。相反，在快捷模型中，Rho GTPase信号直接针对Pol II CTD Ser2和Ser5磷酸化，因此可以迅速带来大规模的基因表达变化。我们 现在有初步证据表明ROP2 GTPase的活动是植物 - 唯一成员 Rho GTPases的ROP亚家族以及CTD Ser2和Ser5磷酸化水平受S状态的影响。 另外，在SULTR1中，ROP GTPase活性较高； 2个突变体。因此，我们假设ROP2及其 功能上冗余的ROP4充当Sultr1中的负调节剂； 2介导的S传感和信号传导。这 拟议的工作旨在填补从Sultr1; 2到Pol II转录的主要空白。具体来说，目标1是测试 ROP2和ROP4 GTPases在SULTR1中充当负调节剂； 2介导的S传感和信号传导 使用遗传和生化方法。 AIM 2是检验ROP2介导的Pol II快捷方式的假设 S响应需要模型。在AIM 3中，我们建议测试ROP2控制的Slim1转录因子 活动和ROP2介导的POL II CTD代码调制法案合作以实现最有生产力的 S缺陷诱导的S响应基因的转录。拟议的研究不仅会导致新颖 机械洞察植物如何使用营养透感Sultr1; 2和ROP信号转换开关 控制基因表达，但也为其他生物体的转录调节提供了范式。