DMA-Tudor interaction modules: a novel approach to Survival Motor Neuron protein (SMN) and Cajal body function

DMA-Tudor 相互作用模块：运动神经元生存蛋白 (SMN) 和 Cajal 身体功能的新方法

• 批准号: 10502150
• 负责人: Karla M Neugebauer
• 金额: $ 44.17万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10502150
• 关键词: Affect; Affinity; Amino Acids; Arginine; Axon; Binding; Binding Proteins; Binding Sites; Biochemistry; Biological Assay; Biotinylation; Cell Nucleus; Cell physiology; Cells; Cellular Stress; Chemicals; Complement; Cytoplasm; Data; Diffuse; Disease; Embryo; Embryonic Development; Etiology; Genetic; Genetic Transcription; Goals; Health; Image; Infant; Ligand Binding; Ligands; Location; Mass Spectrum Analysis; Mediating; Methylation; Microscopy; Missense Mutation; Modification; Molecular; Motor; Motor Neurons; Mus; Muscle; Mutation; Neurons; Nuclear; Optics; Patients; Phenotype; Physical condensation; Play; Positioning Attribute; Post-Translational Protein Processing; Protein Deficiency; Proteins; Publishing; RNA; RNA Processing; Role; SMN protein (spinal muscular atrophy); Site; Source; Specific qualifier value; Specificity; Spinal Muscular Atrophy; Stress; Structure; Testing; Time; Tissues; Toddler; Translations; Zebrafish; arginine methyltransferase; axonal pathfinding; dimethylarginine; fluorescence imaging; genome editing; globular protein; grasp; inhibitor; insight; mortality; mutant; nervous system disorder; neuromuscular system; novel; novel strategies; novel therapeutic intervention; protein complex; protein function; scaffold; tissue/cell culture

Survival Motor Neuron protein (SMN) deficiencies cause Spinal Muscular Atrophy (SMA), the most common genetic cause of infant and toddler mortality. Although SMN has been implicated in transcription, RNA processing and translation, the molecular basis of motoneuron loss is still unknown. We recently discovered a novel activity of SMN: biomolecular condensation caused by SMN’s globular tudor domain (SMNTud), which binds ligands modified by dimethylarginine (DMA). Although there are hundreds of DMA-modified proteins in cells, the correspondence between tudor domains and their DMA ligands remains unknown. This understudied post-translational modification is potentially dynamic and has emerging roles in multiple neurological diseases through the altered functions of cellular compartments known as biomolecular condensates (BMCs). Our central hypothesis is SMNTud binding to DMA ligands plays critical roles in cellular organization, which are especially vulnerable in the neuromuscular system. Our findings highlight a critical need to comprehensively determine the DMA ligands of SMNTud and the activities of the interaction modules they form. SMN is diffusely cytoplasmic and present in nuclear BMCs called Cajal bodies, which are essential for embryonic development. Cajal bodies are scaffolded by a known SMNTud ligand and altered in SMA. During stress, SMN forms BMCs in the cytoplasm. Our preliminary results directly implicate DMA binding and biomolecular condensation in SMA, because SMNTud activity was blocked by a single amino acid mutation, E134K, that blocks binding to DMA ligands and causes SMA. Chemical inhibitors of DMA drastically altered the composition and substructure of Cajal bodies, which we determined for the first time with our collaborator and co-I, Dr Joerg Bewersdorf. The identities of the full complement of DMA ligands that bind SMNTud and those that affect Cajal bodies have been unknown until now. Our preliminary data reveal ~70 novel and specific SMNTud ligands, indicating that new insights relevant to SMA are within our grasp. The overall objectives of this new application are to (i) identify the DMA ligands of SMNTud that mediate biomolecular condensation, (ii) understand the dynamicity of asymmetric (aDMA) and symmetric (sDMA) installed by arginine methyltransferases and removed by demethylases with respect to the structure and function of BMCs, and (iii) reveal novel SMN functions by leveraging DMA-SMNTud interaction modules. Our rationale is that objectives concerning DMA-SMNTud interaction modules will be most accessible to rigorous analysis through a combination of biochemistry and state-of-the-art imaging, using mouse and zebrafish cells and tissues, including motoneurons, with which we have expertise. If achieved, our aims will discover novel SMN binding partners and functions of SMNTud in biomolecular condensation. The regulatory potential and dynamicity of the DMA modification, a source of tissue specificity and disease etiology, will be determined. Identification of DMA-SMNTud interaction modules will suggest new therapeutic approaches for SMA.

生存运动神经元蛋白（SMN）缺陷引起脊柱肌肉萎缩（SMA），这是最常见的 婴儿和幼儿死亡率的遗传原因。尽管在转录中暗示了SMN，但RNA 处理和翻译，运动神经元损失的分子基础仍然未知。我们最近发现了一个 SMN的新活性：由SMN的全球都铎王朝（SMNTUD）引起的生物分子凝结 结合通过二甲基精氨酸（DMA）修饰的配体。尽管有数百种DMA修饰蛋白 在细胞中，都铎式结构域与其DMA配对之间的对应关系尚不清楚。这 研究后翻译后的修饰具有动态性，并且在多个中具有新兴角色 神经疾病通过细胞隔室的变化功能，称为生物分子 冷凝物（BMC）。我们的中心假设是与DMA配体的SMNTUD结合在细胞中起关键作用 组织，在神经肌肉系统中特别容易受到伤害。 我们的发现凸显了全面确定SMNTUD和活动的DMA配体的迫切需求 它们形成的相互作用模块。 SMN是扩散的细胞质，并存在于称为Cajal的核BMC中 身体，这对于胚胎发育至关重要。 Cajal尸体由已知的SMNTUD配体脚手架 并改变了SMA。在压力期间，SMN在细胞质中形成BMC。我们的初步结果直接 暗示SMA中的DMA结合和生物分子冷凝，因为SMNTUD活性被A阻塞 单个氨基酸突变E134K，可阻止与DMA配体结合并引起SMA。化学抑制剂 DMA的大幅改变了Cajal体的组成和亚结构，我们为第一个确定 与我们的合作者和Co-I在一起，Joerg Bewersdorf博士。 DMA配体完整完成的身份 到目前为止，这种结合SMNTUD和影响Cajal体的人已经尚不清楚。我们的初步数据显示 〜70新颖和特定的SMNTUD配体，表明与SMA相关的新见解在我们的掌握之内。 该新应用程序的总体目标是（i）确定介导的Smntud的DMA配体 生物分子凝结，（ii）了解不对称（ADMA）和对称（SDMA）的动态性 由精氨酸甲基转移酶安装，并通过脱甲基酶相对于结构和 BMC和（III）的功能通过利用DMA-SMNTUD相互作用模块来揭示新的SMN功能。我们的 理由是关于DMA-SMNTUD交互模块的目标最容易访问 通过使用小鼠和斑马鱼细胞结合生物化学和最新成像的结合来分析 以及包括运动神经元在内的组织，我们拥有专业知识。如果实现了，我们的目标将发现小说 SMN结合伙伴和SMNTUD在生物分子凝结中的功能。监管潜力和 将确定DMA修饰的动态性（组织特异性和疾病病因的来源）。 DMA-SMNTUD相互作用模块的识别将为SMA提出新的治疗方法。