Nucleocytoplasmic Interactions and Dynamics in Emery-Dreifuss Muscular Dystrophy

埃默里-德莱福斯肌营养不良症的核细胞质相互作用和动力学

• 批准号: 8869806
• 负责人: Gregg G Gundersen
• 金额: $ 52.17万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8869806
• 关键词: Actins; Acute; Affect; Animal Model; Biological Assay; Biological Models; Cell Nucleus; Cell physiology; Cells; Cellular biology; Centrosome; Complex; Coupling; Cytoplasm; Cytoskeleton; Data; Defect; Dyskinetic syndrome; Emery-Dreifuss Muscular Dystrophy; Etiology; Fiber; Fibroblasts; Genes; Health; Injury; Intermediate Filament Proteins; Kinetics; Lamin Type A; Lamins; Link; MAPK3 gene; MEKs; Mediating; Microfilaments; Mitogen-Activated Protein Kinases; Movement; Muscle; Muscle Cells; Muscle Development; Muscle Fibers; Muscle function; Muscular Dystrophies; Mutation; Myoblasts; Myocardium; Myopathy; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Pathogenesis; Phenotype; Phosphotransferases; Physiological; Positioning Attribute; Process; Proteins; Public Health; Research; Series; Signal Transduction; Skeletal Muscle; Striated Muscles; Structure; Testing; United States; Variant; Work; X-linked Emery-Dreifuss muscular dystrophy; base; cell motility; cellular pathology; emerin; env Gene Products; in vivo; inhibitor/antagonist; innovation; insight; migration; mouse model; novel; prevent; protein complex; repaired; research study; wasting

DESCRIPTION (provided by applicant): Emery-Dreifuss muscular dystrophy (EDMD) is caused by mutations in genes encoding proteins of the nuclear envelope. Autosomal EDMD results from mutations in LMNA, which encodes A-type lamins, and X-linked EDMD from mutations in EMD, which encodes emerin. Mutations in genes encoding nesprins and SUNs have also been associated with the EDMD phenotype. The proteins encoded by these genes are involved in connecting the inside of the nucleus to the cytoplasm, forming or associating with the LINC complex. We have shown that LMNA mutations causing autosomal EDMD, as well as deficiency of A-type lamins, block cytoplasmic actin-dependent nuclear movement by disrupting anchoring of the nucleus to structures known as TAN lines, which are composed of SUN2 and nesprin-2. Loss of emerin, as occurs in X-linked EDMD, additionally blocks nuclear movement by altering retrograde cytoplasmic actin flow that drives it. Depletion of SUNs and nesprins also leads to defective nuclear movement by altering TAN line function. In cells lacking A- type lamins, inhibition of ERK1/2, which is activated by alterations in lamins, emerin, SUNs and nesprins as well as in striated muscle of animal models of autosomal EDMD, reverses the nuclear movement defect. We now propose to test the hypothesis that there is a link between genetic alterations that cause EDMD and the nuclear movement defects and ERK1/2 activation they create. To test this hypothesis, we will utilize an innovative fibroblast-based assay to mechanistically dissect defects in nuclear movement and then extend the findings to cultured myoblasts and skeletal muscle in vivo. In Aim 1, we will examine the relationship between LINC complex function, ERK1/2 activity and nuclear movement, with a focus on how hyperactivated ERK1/2 prevents nuclear movement. In Aim 2, we will examine the temporal relationship between nuclear movement and ERK1/2 activity during physiological activation of the kinase and perform a series of biophysical experiments to directly test if moving the nucleus regulates ERK1/2 signaling. In Aims 3 and 4, we will extend our studies into muscle cells, examining how LINC complex proteins and ERK1/2 affect nuclear movement in migrating myoblasts and determining if A-type lamins and emerin affect proper nuclear positioning in muscle, in mouse models of EDMD with alterations in lamins or emerin. Overall, this research will provide novel insights into the cellular pathology of EDMD and simultaneously uncover new information about nuclear movement, a cellular function of broad significance to basic cell biology.

描述（由申请人提供）：Emery-Dreifuss肌营养不良症（EDMD）是由编码核膜蛋白的基因突变引起的。常染色体EDMD由编码A型核纤层蛋白的LMNA突变引起，X连锁EDMD由编码Emerin的EMD突变引起。编码nesprins和SUN的基因突变也与EDMD表型相关。由这些基因编码的蛋白质参与连接细胞核内部与细胞质，形成或与LINC复合体结合。我们已经表明，LMNA突变导致常染色体EDMD，以及A型核纤层蛋白的缺乏，通过破坏细胞核与称为TAN系的结构的锚定来阻断细胞质肌动蛋白依赖性核运动，TAN系由SUN 2和nesprin-2组成。Emerin的缺失，如发生在X连锁EDMD中，通过改变驱动细胞核运动的逆行细胞质肌动蛋白流而另外阻断细胞核运动。在缺乏A型核纤层蛋白的细胞中，ERK 1/2的抑制可逆转核运动缺陷，ERK 1/2是由核纤层蛋白、Emerin、SUN和nesprin以及常染色体EDMD动物模型的横纹肌中的改变激活的.我们现在建议测试的假设，有一个基因改变，导致EDMD和核运动缺陷和ERK 1/2激活它们创建之间的联系。为了验证这一假设，我们将利用一种创新的基于成纤维细胞的检测方法来机械地解剖核运动中的缺陷，然后将研究结果扩展到体内培养的成肌细胞和骨骼肌。在目的1中，我们将研究LINC复合体功能，ERK 1/2活性和核运动之间的关系，重点是过度激活的ERK 1/2如何阻止核运动。在目标2中，我们将研究在激酶的生理激活过程中细胞核运动和ERK 1/2活性之间的时间关系，并进行一系列生物物理实验，以直接测试细胞核运动是否调节ERK 1/2信号传导。在目标3和4中，我们将把我们的研究扩展到肌肉细胞，研究LINC复合物蛋白和ERK 1/2如何影响迁移成肌细胞的核运动，并确定A型核纤层蛋白和emerin是否影响肌肉中适当的核定位，在EDMD小鼠模型中改变核纤层蛋白或emerin。总的来说，这项研究将为EDMD的细胞病理学提供新的见解，同时揭示有关核运动的新信息，这是一种对基础细胞生物学具有广泛意义的细胞功能。