Kinetochore Protein Functions in Synaptogenesis

动粒蛋白在突触发生中的功能

• 批准号: 10891859
• 负责人: Thomas L. Schwarz
• 金额: $ 61.94万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10891859
• 关键词: Alzheimer' s Disease; Axon; Axonal Transport; Binding; Binding Sites; Brain; Cell Nucleus; Cell division; Cells; Centromere; Chromosome Segregation; Chromosome abnormality; Chromosomes; Competence; Complement; Complex; Cytoskeleton; Defect; Dendrites; Dendritic Spines; Development; Drosophila genus; Electron Microscopy; Electrophysiology (science); Embryo; Embryonic Development; Genetic; Growth; Growth Cones; Hippocampus; Kinetochores; Knowledge; Learning; Mechanics; Microtubules; Mitosis; Morphology; Motor Neurons; Muscle; Mutation; Nature; Neurites; Neurodegenerative Disorders; Neuromuscular Junction; Neurons; Phenotype; Plus End of the Microtubule; Post-Translational Protein Processing; Presynaptic Terminals; Process; Property; Proteins; RNA Interference; Rattus; Research; Role; Sensory; Shapes; Signal Transduction; Structure; Surface; Swelling; Synapses; System; Testing; Thinness; Vertebral column; daughter cell; density; fly; knock-down; light microscopy; mutant; neurodevelopment; novel; postmitotic; presynaptic; protein complex; protein function; synaptogenesis

Project Summary From a Drosophila mutant screen for defects in the formation of the embryonic neuromuscular junction (NMJ), we have learned that mutations in components of the kinetochore complex are needed for the transformation of a growth cone into a correctly shaped synaptic connection. Loss of these proteins also alters the structure of sensory dendrites. In cultured mammalian neurons, kinetochore proteins also appear to guide development: their knockdown by RNAi causes an excess of filipodia like protrusions to form on hippocampal dendrites. This is a completely novel function for the kinetochore, a protein complex previously known only to function at the centromere of chromosomes where it is required in dividing cells to “catch” and stabilize spindle microtubules and thereby enable the segregation of chromosomes to the daughter cells. The neuronal phenptypes cannot be explained by defects in chromosome mechanics and therefore we hypothesize a postmitotic function for a “neuro-kinetochore”, a function that is likely to involve the same core property of the centromeric kinetochore: the ability to bind to the plus-ends of microtubules and stabilize them. We propose to test the hypothesis that a complex very much akin to that found at centromeres will function locally in post-mitotic neurons to assist in the transformation of dynamic growth cone microtubules into stable bundles of synaptic microtubules and similarly to stabilize dendritic microtubules and thereby arrest dendrite growth. The proposal makes use of the advantages of both Drosophila and mammalian systems. Aim 1 of this proposal therefore seeks to characterize in greater depth the nature of the defects at the embryonic fly NMJ and in hippocampal dendrites. Aim 2 delves into the mechanism underlying the phenotype by asking whether structure function studies support the hypothesis of a kinetochore-like structure that must bind to microtubules. Aim 3 focuses on the microtubule cytoskeleton and asks whether there are defects in microtubule dynamics and stabilization in the mutants, and how this novel role for kinetochore proteins fits into our knowledge of the processes that transform growth cones into mature endings and determine the morphology of dendrites.

项目摘要 从果蝇突变体筛选胚胎神经肌肉接头（NMJ）形成缺陷， 我们已经了解到， 形成正确形状的突触连接。这些蛋白质的丢失也改变了 感觉树突在培养的哺乳动物神经元中，动粒蛋白似乎也指导发育： 它们被RNAi敲低导致海马树突上形成过量的丝状突起。这 对于动粒来说，这是一个全新的功能，动粒是一种蛋白质复合物，以前只知道在 染色体的着丝粒，在分裂细胞中需要它来“捕获”和稳定纺锤体微管 从而使染色体能够分离到子细胞中。神经元表型不能 可以用染色体力学的缺陷来解释，因此我们假设， “神经动粒”，一种可能涉及着丝粒动粒相同核心性质的功能： 能够与微管的正端结合并稳定它们。我们建议测试的假设， 非常类似于在着丝粒处发现的复合物将在有丝分裂后的神经元中局部地起作用， 动态生长锥微管转化为稳定的突触微管束， 以稳定树枝状微管并由此阻止树枝状晶体生长。该提案利用了 果蝇和哺乳动物系统的优势。因此，本提案的目标1旨在描述 在更深的缺陷的性质在胚胎苍蝇NMJ和海马树突。Aim 2 通过询问结构功能研究是否支持 一种必须与微管结合的类似运动舞蹈的结构的假说。目标3聚焦于微管 细胞骨架，并询问突变体中微管动力学和稳定性是否存在缺陷， 动粒蛋白的这种新作用如何符合我们对改变生长过程的认识 锥成成熟的结束，并确定树突的形态。