Thyroid Hormone Receptor Isoform-Specific Actions

甲状腺激素受体亚型特异性作用

• 批准号: 8638458
• 负责人: GREGORY A BRENT
• 金额: $ 33.5万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8638458
• 关键词: Adipocytes; Adult; Amino Acids; Amphibia; Binding; Binding Sites; Biological Assay; Biological Metamorphosis; Body Composition; Body Weight; Body Weight decreased; Catecholamines; Cell physiology; Cholesterol; Cholesterol Homeostasis; Consensus; Development; Dominant-Negative Mutation; Dyslipidemias; Energy Metabolism; Enzymes; Family; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Genome; Growth and Development function; Infusion procedures; Lead; Ligands; Liver; Lysine; Mammals; Mediating; Metabolic; Metabolic Diseases; Metabolic Pathway; Metabolism; Mitochondria; Mus; Mutant Strains Mice; Mutation; Nuclear; Nuclear Hormone Receptors; Nuclear Receptors; Obesity; Pathway interactions; Pattern; Peptide Hydrolases; Peroxisome Proliferator-Activated Receptors; Phenotype; Play; Post-Translational Protein Processing; Protein Isoforms; Proteins; Regulation; Reporting; Repression; Respiration; Rest; Role; Signal Pathway; Signal Transduction; Site; Small Ubiquitin-Related Modifier Proteins; Specificity; Thermogenesis; Thyroid Gland; Thyroid Hormone Receptor; Thyroid Hormone Receptor Gene; Thyroid Hormones; Tissues; Transfection; Triiodothyronine; Ubiquitin; adipocyte differentiation; chromatin immunoprecipitation; gene induction; gene induction/repression; genome-wide; hormone regulation; in vitro Model; lipid biosynthesis; mouse model; mutant; neural growth; novel; perilipin; public health relevance; receptor; response; sulfoenolpyruvate; therapeutic target; transcription factor; ubiquitin-protein ligase; uncoupling protein 1

PROJECT SUMMARY Thyroid hormone is essential for normal development, growth, neural differentiation, and metabolic regulation in mammals, and is required for amphibian metamorphosis. There are two thyroid hormone receptor (TR) genes, TR¿ and TR¿, with different patterns of expression in development and in adult tissues. The relevance of TR isoform specificity is strongly supported by the distinct phenotypes reported in families heterozygous for dominant negative mutations of the TR¿ gene and TR¿ gene. The mechanism of TR isoform-specific action, however, is not well understood. Posttranslational modification of nuclear receptors is being increasingly recognized as an important mechanism of gene regulation. Most proteins modified by small ubiquitin-like modifier (SUMO) are transcription factors and nuclear hormone receptors. Sumoylation requires conjugation of SUMO to a lysine within the consensus recognition motif ¿-Lys-X-Glu (¿ is a large hydrophobic amino acid) of a protein, which rapidly and dynamically modifies proteins involved in cellular processes. We determined that posttranslational modification of TR by conjugation of SUMO to TR¿ at lysines 283 and 389, and TR¿ at lysines 50, 146 and 443, plays an essential role in triiodothyronine (T3)-induced gene induction and repression as well as TR isoform-specificity. TR¿-SUMO conjugation is ligand independent and utilizes the E3 ligase PIASxb. TR¿-SUMO is ligand dependent and utilizes predominantly the E3 ligase PIAS1. SUMO1 and SUMO3 conjugation to TR are required for T3-dependent gene regulation, as demonstrated in transient transfection assay and studies of endogenous gene regulation. The role of SUMO1 and SUMO3 in T3-induction in transient functional assays is closely matched to the pattern of TR and co-factor binding in regulation of endogenous genes, as determined by Chromatin Immunoprecipitation (ChIP) assays. Co-repressors play an essential role in thyroid hormone action, and TR sumoylation is important for co-repressor recruitment. We have demonstrated that TR sumoylation is important for thyroid hormone-regulated metabolic actions including adipocyte differentiation and cross-talk with important metabolic regulators including LXR and PPAR¿. Specific aims that will be pursued include; 1. Utilize in vitro models to determine the role of TR sumoylation and TR¿/TR¿ isoform-specific actions in metabolic regulation. 2. Determine how sumoylation modulates TR- mediated gene regulation including TR interaction with transcription co-factors, metabolic signaling pathways, and recognition and binding to T3-regulated genes. 3. Evaluate the influence of TR¿ and TR¿ sumoylation site mutations on thyroid hormone regulation of metabolism in a mouse model. We will assess the impact of introducing TR¿ (K389Q) and TR¿ (K443Q) gene sumoylation mutantions on the thyroid hormone axis, tissue level thyroid status, and metabolic regulation. Understanding the role of TR sumoylation in metabolic regulation and TR-isoform specific action may lead to the identification of novel thyroid hormone signaling targets relevant to therapies for metabolic diseases, including dyslipidemia and obesity.

项目摘要 甲状腺龙骨对于正常发育，生长，神经元分化和代谢调节至关重要 在哺乳动物中，是两栖动物变形所必需的。有两个甲状腺马酮受体（TR） 基因，trâ和tr¿，在发育和成人组织中具有不同的表达模式。相关性 在杂合的家族中报道的明显表型强烈支持Tr同工型的特异性。 tr trood基因和tr¿基因的主要阴性突变。 Tr同工特异性作用的机制， 但是，不太了解。核接收器的翻译后修改正在越来越多 被认为是基因调节的重要机制。大多数由小泛素样修饰的蛋白质 修饰符（SUMO）是转录因子和核骑马接收器。 sumoylation需要共轭 在共识识别基序内的赖氨酸 - lys-x-glu（是大的疏水氨基酸）中的赖氨酸 一种蛋白质，可以快速和动态地修饰参与细胞过程的蛋白质。我们确定了这一点 通过Sumo与Tr的结合在赖氨酸283和389的Tr上进行翻译后TR修饰，然后在 赖氨酸50、146和443在三碘甲醇（T3）诱导的基因诱导和表达中起着至关重要的作用 以及TR同工型特异性。 tr¿-sumo结合是独立的，并利用E3连接酶 PIASXB。 tr¿ -Sumo是配体依赖性的，主要利用E3连接酶PIAS1。 SUMO1和SUMO3 T3依赖性基因调节需要与TR结合，如瞬态转染所示 内源基因调节的测定和研究。 SUMO1和SUMO3在T3诱导中的作用在瞬态 功能测定与内源性调节中的TR和辅助因子结合的模式紧密匹配 基因，由染色质免疫沉淀（CHIP）测定。共抑制器起着至关重要的作用 在甲状腺同性恋动作中，TR sumoylation对于共抑制招募很重要。我们有 证明Tr sumoylation对于甲状腺骑马调节的代谢作用很重要 脂肪细胞分化和与重要的代谢调节剂在内的互换，包括LXR和PPAR。具体的 将追求的目标包括； 1。利用体外模型来确定tr sumoylation和 代谢调节中的Trâ /tr¿同工型特异性作用。 2。确定sumoylation如何调节tr- 介导的基因调节，包括与转录共同因素，代谢信号通路相互作用， 识别并与T3调节的基因结合。 3。评估tr troo和tr sumoylation网站的影响 小鼠模型中代谢的甲状腺马酮调节突变。我们将评估 引入甲状腺激素轴上的TRO（K389Q）和TR？（K443Q）基因sumoylation突变体 甲状腺状态水平和代谢调节。了解TR Sumoylation在代谢调节中的作用 和Tr-异型特异性作用可能导致鉴定新型甲状腺激素信号传导目标相关 用于代谢疾病的疗法，包括血脂异常和肥胖症。