Mechanisms of Golgi Vesiculation during Mitosis

有丝分裂期间高尔基体形成水泡的机制

• 批准号: 7260190
• 负责人: VIVEK MALHOTRA
• 金额: $ 34.85万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7260190
• 关键词: Address; Antimitotic Agents; Binding; C-terminal; Cell Cycle; Cell Cycle Checkpoint; Cells; Class; Collection; Dimensions; Drosophila genome; Elements; Endoplasmic Reticulum; Enzymes; Event; G-Protein-Coupled Receptors; Genome; Golgi Apparatus; Guanosine Triphosphate Phosphohydrolases; Hand; Homologous Gene; Human; Libraries; Lipase; MAP Kinase Gene; MAP2K1 gene; Mammalian Cell; Membrane; Membrane Proteins; Mitogen-Activated Protein Kinases; Mitosis; Mitotic; Mitotic spindle; Molecular Motors; Numbers; Organelles; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Process; Protein Binding; Protein Dephosphorylation; Protein Isoforms; Proteins; RNA Splicing; Recruitment Activity; Regulation; Reporting; Research Personnel; Role; Screening procedure; Signal Transduction; Testing; Variant; Vesicle; Work; daughter cell; human PLK1 protein; novel; numb protein; prevent; programs; transmission process

DESCRIPTION (provided by applicant): The pericentriolar inter connected stacks of Golgi cisternae are fragmented in mitotic mammalian cells. Why do these membranes undergo such a drastic change in their organization and by what mechanism? Do Golgi membranes fuse with the endoplasmic reticulum (ER) during mitosis and therefore use ER for their transmission into daughter cells? Our recent findings reveal that Golgi membranes do not fuse with the ER during mitosis. These findings resolve a long-standing controversy. We have found that inhibiting Golgi fragmentation prevents entry into mitosis. We have proposed the existence of a Golgi membrane specific cell-cycle checkpoint. We have found that kinases MEK1 and Polo like kinase (Plk); and Golgi associated proteins GRASP55 and GRASP65 are required for Golgi fragmentation. Our hypothesis is that MEK1 activates a novel spliced variant of ERK called ERK1c, which phosphorylates GRASP55 to disconnect Golgi stacks. This event occurs in G2 and it is necessary for entry into mitosis. Plk on the other hand, we suggest phosphorylates GRASP65. The phosphorylated GRASP65 recruits a novel protein called Gip (GRASP interacting protein) and this event is necessary for GRASP65 dependent regulation of spindle dynamics in mitosis. A new screen has revealed a number of proteins that regulate the dimensions of Golgi stacks and our hypothesis is that these proteins are modified (by phosphorylation/dephosphorylation) to reorganize Golgi membranes during mitosis. Finally, we are screening 5000 human enzymes (kinase, phosphatase, lipases, GTPases etc) to identify components that control, through the organization of Golgi apparatus, entry of cells into mitosis. Our findings will reveal the mechanism by which, cells duplicate their essential organelles during the cell cycle, and how Golgi membranes in turn through their organization, control mitotic entry

描述（由申请人提供）：在有丝分裂的哺乳动物细胞中，高尔基池的中心周围相互连接的堆叠是碎片化的。为什么这些膜的组织会发生如此剧烈的变化，又是通过什么机制发生的？在有丝分裂过程中，高尔基膜是否与内质网（ER）融合，从而利用内质网将其传递到子细胞中？我们最近的研究结果表明，在有丝分裂过程中，高尔基体膜不与内质网融合。这些发现解决了一个长期存在的争议。我们发现抑制高尔基体分裂阻止进入有丝分裂。我们提出了高尔基膜特异性细胞周期检查点的存在。我们发现激酶MEK1和Polo样激酶（Plk）；和高尔基相关蛋白GRASP55和GRASP65是高尔基断裂所必需的。我们的假设是，MEK1激活了ERK的一种新的剪接变体，称为ERK1c，它磷酸化GRASP55以断开高尔基堆叠。这一事件发生在G2，是进入有丝分裂所必需的。另一方面，我们认为Plk会磷酸化GRASP65。磷酸化的GRASP65募集了一种名为Gip （GRASP相互作用蛋白）的新蛋白，这一事件对于GRASP65依赖性的有丝分裂纺锤体动力学调节是必要的。一项新的筛选发现了一些调节高尔基堆积尺寸的蛋白质，我们的假设是这些蛋白质在有丝分裂期间被修饰（通过磷酸化/去磷酸化）以重组高尔基膜。最后，我们正在筛选5000种人类酶（激酶、磷酸酶、脂肪酶、gtpase等），以确定通过高尔基体组织控制细胞进入有丝分裂的成分。我们的发现将揭示细胞在细胞周期中复制其基本细胞器的机制，以及高尔基膜如何通过其组织反过来控制有丝分裂的进入