Function and Mechanism of CUL4 E3 Ligases in Human Diseases

CUL4 E3 连接酶在人类疾病中的功能和机制

• 批准号: 8642184
• 负责人: YUE XIONG
• 金额: $ 35.83万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8642184
• 关键词: ADRBK1 gene; Adrenergic Receptor; Agonist; Alzheimer' s Disease; Back; Binding; Brain; CDT1 Gene; CUL3 gene; CUL4A gene; Cardiovascular Diseases; Cell Proliferation; Cell physiology; Cells; Chromatin; Complex; Cullin Proteins; DNA; DNA Replication Factor; DNA biosynthesis; Data; Defect; Embryo; Epigenetic Process; Family; Funding; G Protein-Coupled Receptor Signaling; G protein coupled receptor kinase; G-substrate; GRK; GTP-Binding Proteins; Gene Expression; Gene Expression Regulation; Genes; Goals; Heart Diseases; Heart failure; Histones; Human; Insulin Resistance; Investigation; Licensing Factor; Ligase; Link; Mediating; Molecular; Mus; Mutant Strains Mice; Mutate; Myocardial Infarction; Neurologic Mutants Mice; Neurons; Nuclear; Organism; Pathway interactions; Patients; Physiology; Play; Portal Hypertension; Protein Subunits; Proteins; Publishing; RBX1 gene; Receptor Signaling; Regulation; Replication Licensing; Research; Role; Signal Pathway; System; Therapeutic Intervention; Tumor Suppressor Proteins; Ubiquitin; X-Linked Mental Retardation; X-linked mental retardation 1; base; chromatin modification; cullin-3; heart function; human RBX1 protein; human disease; in vivo; innovation; insight; mouse model; novel; protein degradation; response; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Most, if not all, cellular processes are regulated by timely degradation of regulatory proteins through the ubiquitin system. Specific substrate proteins are targeted for degradation through the activity of E3 ubiquitin ligases. We previously discovered that two small RING finger proteins, ROC1 and ROC2, function as the essential catalytic components of the largest family of E3 ligase complexes, the cullin-RING E3 ligases (CRLs). We also discovered that cullin 3 and cullin 4 could assemble as many as 200 and 100 distinct CRL3 and CRL4 E3 complexes, respectively. In this application, we propose two lines of research aimed at understanding the function and mechanism of two specific CRL4 E3 ubiquitin ligase complexes, CRL4G¿2, and CRL4WDR5, and how alterations of these CRL4 complexes contribute to two major human diseases, heart failure and X-linked mental retardation. In the first Aim, we will examine the molecular function of CRL4 G¿2 and its role in cardiovascular disease. We present data demonstrating that a WD40 protein, G-protein ¿ subunit 2 (G¿2), associates with DDB1- CUL4A to target G protein-coupled receptor kinases (GRK2), for ubiquitylation. Elevated GRK2 has previously been associated with myocardial infarction, heart failure, portal hypertension, insulin resistance, and Alzheimer's disease. We propose first to explore how broadly CRL4 is involved in the regulation of G- protein coupled receptor (GPCR) signaling by determining the interaction of CRL4 with other G¿ and GRK proteins. We will then focus on one well-characterized GPCR signaling pathway, ¿-adrenergic receptors (¿ - AR) signaling, to determine the mechanism of CRL4G¿2 mediated GRK2 ubiquitylation. We will also determine whether loss of Cul4a impairs heart function in mouse. In the second Aim, we present data demonstrating that CUL4B, one of the most frequently mutated genes in X-linked mental retardation (XLMR) patients, but not CUL4A, is a nuclear E3 ligase of WDR5, a WD40 protein and an essential component for histone H3K4 trimethylation. We propose to determine the function of CUL4B-mediated WDR5 ubiquitylation in neuronal cell proliferation, survival and differentiation. We also propose to develop and characterize a novel mouse model, conditional Cul4b mutant mouse strain, to determine the function of Cul4b in brain. Finally, we propose to determine broadly the function of CUL4B in the regulation of chromatin modification and gene expression.

描述（由申请人提供）：大多数（如果不是全部）细胞过程是通过泛素系统及时降解调节蛋白来调节的，特定的底物蛋白是通过 E3 泛素连接酶的活性进行降解的。指状蛋白 ROC1 和 ROC2 是最大的 E3 连接酶复合物家族（cullin-RING E3 连接酶）的重要催化成分我们还发现 cullin 3 和 cullin 4 可以分别组装多达 200 个和 100 个不同的 CRL3 和 CRL4 E3 复合物。在本应用中，我们进行了两项研究，旨在了解两种特定 CRL4 的功能和机制。 E3 泛素连接酶复合物，CRL4G¿ 2、CRL4WDR5，以及这些 CRL4 复合物的改变如何导致两种主要的人类疾病：心力衰竭和 X 连锁智力迟钝。在第一个目标中，我们将检查 CRL4 G¿ 的分子功能。 2 及其在心血管疾病中的作用 我们提供的数据证明 WD40 蛋白、G 蛋白 ¿亚基 2 (G¿2) 与 DDB1-CUL4A 结合，靶向 G 蛋白偶联受体激酶 (GRK2)，导致 GRK2 升高，此前已被认为与心肌梗塞、心力衰竭、门静脉高压、胰岛素抵抗和阿尔茨海默氏病有关。我们建议首先通过确定 CRL4 与其他受体的相互作用来探索 CRL4 在 G 蛋白偶联受体 (GPCR) 信号传导调节中的广泛参与。 G??然后我们将重点关注一种已充分表征的 GPCR 信号通路 ¿ -肾上腺素能受体 (¿ - AR) 信号传导，以确定 CRL4G¿ 的机制我们还将确定 Cul4a 的缺失是否会损害小鼠的心脏功能。在第二个目标中，我们提供的数据证明 CUL4B 是 X 连锁智力低下 (XLMR) 患者中最常见的突变基因之一。不是 CUL4A，是 WDR5 的核 E3 连接酶，WDR5 是 WD40 蛋白，也是组蛋白 H3K4 三甲基化的重要组成部分。我们还建议开发并表征一种新的小鼠模型，即条件性 Cul4b 突变小鼠品系，以确定 Cul4b 在大脑中的功能。 CUL4B 在染色质修饰和基因表达调节中的功能。