CELL CYCLE REGULATION OF GOLGI MEMBRANE DYNAMICS

 描述(申请人提供)：细胞增殖严重依赖于间期的复制细胞器和有丝分裂过程中两个子细胞之间的分离。染色体和细胞内细胞器的准确划分对于维持细胞的世代功能至关重要。有丝分裂的缺陷可导致基因组不稳定和重要细胞器的丧失，这通常与癌症的发展有关。虽然在理解染色体分离方面已经取得了很大进展，但支配重要细胞器，特别是高尔基体分裂的机制仍然很不清楚。哺乳动物的高尔基体对分泌是必不可少的，有丝分裂后细胞的生存取决于一个功能性高尔基体的子代分裂。我们的目标是确定在有丝分裂过程中确保单个哺乳动物高尔基体忠实分裂的潜在机制。在有丝分裂开始时，高度组织化的高尔基体结构在两个子细胞中均匀分裂后形成囊泡并进行改造。我们之前展示了纺锤体主动分割哺乳动物高尔基体。这一过程由高尔基体膜蛋白GM130启动，高尔基体膜蛋白GM130局部激活纺锤体组装因子TPX2，启动微管聚合。形成的微管进一步被GM130捕获和捆绑，从而将高尔基体膜连接到纺锤体上，以确保高尔基体分离到子细胞中。在这项提案中，我们计划确定这一过程的生化和机械基础。我们的目标是确定GM130在有丝分裂中结合伙伴和功能切换的分子基础；剖析GM130在高尔基体衍生纺锤体组装中微管成核、捆绑和RAN依赖中的功能；并阐明高尔基体囊泡在有丝分裂进程中的作用。总之，这些研究将为有丝分裂的调控和高尔基体的分裂过程提供新的分子机制见解。

 DESCRIPTION (provided by applicant): Cell proliferation critically depends on the duplication organelles in interphase and the segregation between the two daughter cells during mitosis. Accurate partitioning of chromosomes and intracellular organelles is crucial to sustain cellular functions over generations. Defects in mitosis can lead to genomic instability and loss of vital organelles, which is commonly associated with the development of cancer. While much progress has been made towards understanding the segregation of chromosomes, the mechanisms that govern the partitioning of vital organelles, in particular of the Golgi, remain largely unknown. The mammalian Golgi is essential for secretion and post-mitotic cell survival depends on the partitioning of a functional Golgi into progeny. Our aim is to define the underlying mechanisms that ensure the faithful partitioning of the single mammalian Golgi during mitosis. At the onset of mitosis, the highly organized Golgi structure vesiculates and reforms after equal partitioning in the two daughter cells. We previously showed that the spindle actively partitions the mammalian Golgi. This process is initiated by the Golgi membrane protein GM130, which locally activates the spindle assembly factor TPX2 to initiate microtubule polymerization. Forming microtubules are further captured and bundled by GM130, thereby linking Golgi membranes to the spindle to ensure the Golgi segregation into the daughter cells. In this proposal we plan to determine the biochemical and mechanistic basis for this process. Our aims are to determine the molecular basis for binding partner and functional switching of GM130 in mitosis; to dissect GM130 functions in microtubule nucleation, bundling and Ran dependency in Golgi-derived spindle assembly; and to elucidate the role of Golgi vesiculation in mitotic progression. Together these studies will provide new molecular mechanistic insights into the regulation of mitosis and the division process of the Golgi apparatus.