Structure-Function of the Nuclear Envelope Bridge and its Role in Laminopathies

核膜桥的结构-功能及其在核纤层蛋白病中的作用

• 批准号: 8174164
• 负责人: Thomas Schwartz
• 金额: $ 22.08万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8174164
• 关键词: Affect; Animal Model; Anodes; Binding; Biochemical; Cell Nucleus; Cells; Cerebellar Ataxia; Chromatin; Chromosome Pairing; Complex; Cytoplasm; Cytoskeleton; Data; Defect; Deformity; Development; Disease; Drug Delivery Systems; Drug Design; Emery-Dreifuss Muscular Dystrophy; Escherichia coli; Etiology; Face; Funding; Future; Generations; Genetic Screening; Hand; Health; Heart; Human; Joints; Knock-out; Lamin Type A; Lamin Type B; Lead; Life; Light; Link; Malignant Neoplasms; Mammalian Cell; Mechanics; Meiosis; Membrane; Methods; Molecular; Molecular Target; Morphology; Mus; Muscle; Muscle Cells; Muscle Development; Muscular Dystrophies; Mutation; Myopathy; Neurologic; Neurons; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Lamina; Nuclear Outer Membrane; Nuclear Pore Complex; Pathology; Patients; Peptides; Physiology; Positioning Attribute; Process; Progeria; Property; Proteins; Recombinants; Regulation; Research; Roentgen Rays; Role; Sequence Homology; Signal Transduction; Specificity; Structural Protein; Structure; Sudden Death; System; Testing; Transport Process; United States; Work; X-Ray Crystallography; base; design; env Gene Products; human disease; insight; lissencephaly; migration; milligram; mutant; nervous system disorder; novel strategies; premature; programs; protein complex; tool; wasting

DESCRIPTION (provided by applicant): In mammalian cells, the structural integrity of the nucleus is conferred by A- and B-type lamins, a meshwork of proteins that lines the nucleoplasmic face of the nuclear envelope and forms the nuclear lamina. Mutations scattered along LMNA, which encodes A-type lamins, as well as mutations within other nuclear envelope proteins are associated with a broad range of human diseases, collectively called laminopathies. The molecular etiology of these diseases remains unknown. The recent characterization of the LINC complex, an evolutionary-conserved protein complex that bridges the inner and outer membranes of the nuclear envelope and physically connects the nuclear lamina to the cytoskeleton of mammalian cells, suggests that the nucleus is directly tethered to the cytoskeleton. This structural linkage is crucial for at least two reasons: (1) it is important to maintain nuclear morphology per se and (2) it allows mechanical force to be exerted upon the nucleus to move it within the cell, a process vitally important in muscle and nerve cell development, for example. At the center of the LINC complex is the interaction between SUN domain containing proteins of the inner nuclear membrane and KASH-peptide-containing proteins of the outer nuclear membrane. SUN and KASH interact directly and specifically in the perinuclear space. In many of the laminopathies, including the severe muscle disease, Emery-Dreifuss muscular dystrophy, neurological disorders such as cerebellar ataxia, and progeria the SUN-KASH interaction within the LINC complex is lost, resulting in severe consequences for nuclear morphology and positioning. In humans, at least five LINC complexes exist, each containing a different pair of SUN- and KASH-containing proteins. Signaling between these components is poorly understood. At the center of this proposal is the elucidation of the structure and function of the SUN-KASH interaction using biochemical and X-ray crystallographic tools. The atomic structure of the SUN-KASH complex should provide valuable insight into the regulation of this interaction. Despite the importance of the SUN-KASH complex for human physiology and pathology, its structure is still unknown. This can largely be attributed to the problems with obtaining sufficient quantities of the proteins for structural studies. We have developed a method to overcome these obstacles and are now able to pursue quantitative structure-function analysis. We anticipate that this project will shed light on the biophysical principles behind the nucleo-cytoskeletal connection established through LINC complexes. We will identify by X-ray crystallography the specific molecular details that regulate this conserved interconnection. In parallel, we will perform detailed biochemical and mutational analysis of the SUN-KASH complex. This study has the potential to enable the structural and molecular characterization of the entire LINC complex, including all other components. In consequence, this project should establish new drug targets for the cure of a broad array of laminopathies. PUBLIC HEALTH RELEVANCE: Muscular dystrophies collectively have a high impact on health, affecting tens of thousands of people in the United States alone. Emery-Dreifuss muscular is characterized by wasting of certain muscles, joint deformities and life-threatening heart problems that can result in premature and sudden death. There is currently no definitive therapy for Emery-Dreifuss muscular dystrophy or related diseases; therefore, the work in this project is designed to identify molecular targets that can lead to treatments for patients.

描述（由申请人提供）：在哺乳动物细胞中，核的结构完整性由a-和b型层粘蛋白（蛋白质的网状工厂）赋予，该蛋白质是核包膜的核质面并形成核层的蛋白质。沿LMNA散布的突变，该突变编码A型层粘连蛋白以及其他核包膜蛋白内的突变与广泛的人类疾病有关，共同称为椎板病。这些疾病的分子病因仍然未知。 LINC复合物（一种进化保存的蛋白质复合物）的最新表征桥接了核包络的内部和外膜，并将核薄片与哺乳动物细胞的细胞骨架进行物理连接起来，这表明核直接将核直接绑在细胞骨架上。这种结构上的联系至少有两个原因至关重要：（1）保持核形态本身很重要，（2）它允许将机械力施加在细胞核上以将其移动到细胞中，例如，在肌肉和神经细胞发育中至关重要的过程。在林克复合物的中心是含有内部核膜的蛋白质和外核膜的含Kash肽的蛋白质之间的相互作用。太阳和卡什在核周空间中直接相互作用。在许多层状病毒中，包括严重的肌肉疾病，埃默里 - 雷氏肌肉营养不良，小脑共济失调等神经系统疾病以及linc综合体内的Sun-kash相互作用丧失，从而丢失了Sun-Kash相互作用，从而导致核形态和定位的严重后果。在人类中，至少存在五个林族复合物，每种含有不同的含有太阳和含卡什的蛋白质。这些组件之间的信号传导知之甚少。该建议的中心是使用生化和X射线晶体学工具阐明Sun-Kash相互作用的结构和功能。 Sun-Kash综合体的原子结构应为这种相互作用的调节提供宝贵的见解。尽管Sun-Kash复合物对人类的生理和病理非常重要，但其结构仍然未知。这在很大程度上可以归因于获得足够数量的蛋白质进行结构研究的问题。我们已经开发了一种克服这些障碍的方法，现在能够进行定量结构功能分析。我们预计该项目将阐明通过LINC复合物建立的核骨骨骼连接背后的生物物理原理。我们将通过X射线晶体学识别调节这种保守互连的特定分子细节。同时，我们将对Sun-Kash复合物进行详细的生化和突变分析。这项研究有可能使整个LINC复合物（包括所有其他成分）的结构和分子表征能够实现结构和分子表征。因此，该项目应建立新的药物靶标，以治愈各种各样的椎板病。 公共卫生相关性：肌肉营养不良群体对健康产生很大影响，仅影响了美国成千上万的人。 Emery-Dreifuss的肌肉的特征是浪费了某些肌肉，关节畸形和威胁生命的心脏问题，这可能导致过早和猝死。目前尚无针对埃默里 - 雷夫斯肌肉营养不良或相关疾病的明确疗法。因此，该项目的工作旨在确定可以导致患者治疗的分子靶标。