MOLECULAR MECHANISMS OF PHYTOCHROME SIGNALING

光敏色素信号传导的分子机制

• 批准号: 8440083
• 负责人: JOHN CLARK LAGARIAS
• 金额: $ 32.55万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-05 至 2016-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8440083
• 关键词: Address; Agriculture; Arabidopsis; Architecture; Bacteria; Behavior; Bilin; Biochemical; Biological; Biology; Biophotonics; Brown Algae; Cell Nucleus; Characteristics; Comparative Biochemistry; Coupling; Cryptophyta; Cyanobacterium; Cyanophora paradoxa; Detection; Development; Diatoms; Disease; Distant; Environment; Enzymatic Biochemistry; Evolution; Experimental Designs; Flowers; Food; Gene Expression; Genome; Germination; Grant; Green Algae; Harvest; Health; Human; Investigation; Knowledge; Left; Life; Light; Malnutrition; Mediating; Medicine; Modeling; Molecular; Molecular Biology; Molecular Genetics; Mouse-ear Cress; Nuclear; Nuclear Translocation; Organelles; Organism; Output; Pathway interactions; Perception; Phosphotransferases; Photochemistry; Photoreceptors; Phytochrome; Plants; Population; Process; Protein Biochemistry; Protein Family; Proteins; Proteobacteria; Research; Rice; Role; Scheme; Seedling; Seeds; Sexual Development; Signal Transduction; Spectrum Analysis; Structure; Sunlight; Synthesis Chemistry; System; Testing; Tetrapyrroles; Translations; Triticum aestivum; Wheat; Work; base; burden of illness; chromophore; circadian pacemaker; comparative; density; disability; fundamental research; fungus; human mortality; improved; in vivo; innovation; insight; next generation; nutrition; optogenetics; public health relevance; reproductive development; response; sensor; tool; transmission process

DESCRIPTION (provided by applicant): This project, entitled "Molecular Mechanisms of Phytochrome Signaling" (PI J. Clark Lagarias, UC Davis), focuses on gaining fundamental knowledge about the phytochrome family of protein light sensors. Phytochromes utilize linear tetrapyrroles (bilins) as chromophores to sense light quality, quantity and duration. Photochemical light sensing triggers conformational changes that modulate the behavior of living systems via target molecules that regulate downstream transcriptional cascades. The proposed investigations address the hypothesis that the fundamental mechanism of light sensing has remained conserved throughout billions of years of evolution since endosymbiotic capture of a cyanobacterium by a eukaryotic host. There are three specific aims focused on conservation of photoconversion and protein-chromophore interactions in plant and cyanobacterial phytochromes, the evolutionary genesis of plant phytochrome, and phytochrome photoconversion and signaling activity in land plants. By examining phytochromes from evolutionarily distant species ranging from cyanobacteria to plants, our studies seek to elucidate the basis of light sensing and the intramolecular structural changes that are used to control gene expression. Phytochromes from the glaucophyte Cyanophora paradoxa, the chlorophyte Micromonas pusilla, and the land plants Arabidopsis thaliana and Triticum aestivum (wheat), will be used to examine the hypothesis that light-regulated conformational change triggers translocation to the nucleus in all extant eukaryotic phytochromes. To test these hypotheses, we leverage computational analyses to guide experimental design, protein biochemistry and molecular biology to express and purify photoreceptors, enzymology and spectroscopy to understand light-induced changes in photoreceptor structure, and in vivo assessment of nuclear translocation and function in the model land plant Arabidopsis thaliana. Significance. Studies on phytochromes provide fundamental knowledge about how living systems regulate their behavior in response to the external environment. Phytochromes are key regulators for triggering seed germination, initiating early development of the seedling, and inducing flowering (sexual development). Because of their role in shade sensing, phytochromes are an important limiting factor for yield at high crop densities in modern agriculture. Application of the insights from our studies can improve nutrition, enhancing health, lengthening life, and reducing the burdens of illness and disability. Moreover, photosensory proteins are valuable tools for studying function and localization of mammalian proteins (optogenetics), and this work yields new tools for fundamental research into such systems.

描述（由申请人提供）：该项目，题为“光敏色素信号传导的分子机制”（PI J. Clark Lagarias，加州大学戴维斯分校），侧重于获得有关光敏色素家族蛋白质光传感器的基础知识。光敏色素利用线性四吡咯（胆色素）作为发色团来感知光的质量、数量和持续时间。光化学光感应触发构象变化，通过调节下游转录级联的靶分子调节生命系统的行为。拟议的调查解决的假设，光传感的基本机制一直保持保守的整个数十亿年的进化，因为内共生捕获的蓝藻由真核宿主。有三个具体的目标集中在植物和蓝藻光敏色素的光转换和蛋白质-发色团相互作用的保护，植物光敏色素的进化起源，以及陆地植物光敏色素的光转换和信号传导活性。通过研究从蓝细菌到植物的进化上遥远的物种的光敏色素，我们的研究试图阐明光传感和用于控制基因表达的分子内结构变化的基础。从蓝绿藻蓝藻paradoxa，叶绿素微单胞菌pusilla，和陆地植物拟南芥和小麦（小麦）的光敏色素，将被用来检查的假设，光调节构象变化触发易位到细胞核中的所有现存的真核生物光敏色素。为了验证这些假设，我们利用计算分析来指导实验设计，蛋白质生物化学和分子生物学来表达和纯化光感受器，酶学和光谱学来了解光诱导的光感受器结构变化，以及在模型陆地植物拟南芥中对核转位和功能的体内评估。意义对光敏色素的研究提供了关于生命系统如何调节其行为以应对外部环境的基本知识。光敏色素是触发种子萌发、启动幼苗早期发育和诱导开花（性发育）的关键调节剂。由于光敏色素在阴影感应中的作用，它们是现代农业中高作物密度下产量的重要限制因素。应用我们的见解 研究可以改善营养，增进健康，延长寿命，减少疾病和残疾的负担。此外，感光蛋白是研究哺乳动物蛋白质功能和定位（光遗传学）的宝贵工具，这项工作为此类系统的基础研究提供了新的工具。