Defining the regulatory role of mitotic cyclins on Endoplasmic Reticulum reorgani

描述（由申请人提供）：主要细胞功能，如蛋白质合成和折叠、脂质合成、细胞内钙储存和大分子的核转运都依赖于内质网（ER）。ER结构或功能的失效与许多慢性疾病如2型糖尿病和自闭症以及神经退行性疾病如遗传性痉挛性截瘫（HSP）和阿尔茨海默病有关。在有丝分裂期间，ER形态发生显著变化，这是适当的膜分配和核膜形成所必需的现象。有丝分裂雌激素受体的变化是如何发生的，它们是如何被调节的，或者哪些分子机制是这些变化的原因，目前还知之甚少。有丝分裂细胞周期蛋白：Cdk激酶复合物是细胞分裂过程中细胞核和细胞骨架动力学的主要调节因子，但它们参与有丝分裂内质网重组尚不清楚。此外，由于小GTP酶的Ras超家族成员控制有丝分裂期间的变化，因此它们可能驱动有丝分裂ER动力学。事实上，最近发现Rab5 GTdR在有丝分裂ER结构中具有独立于其内吞作用的作用。因此，探索这些蛋白质如何影响内质网形态是一个关键问题要解决。本项目的目标是确定有丝分裂过程中有丝分裂细胞周期蛋白：Cdk对ER重组的调控，并确定一种分子途径，协调有丝分裂ER重组与Rab5 GTdR活性。这些过程将在模式生物黑腹果蝇的胚胎中详细研究。早期果蝇胚胎是研究有丝分裂的理想材料，因为它的细胞周期快速、缩短，最初的几轮有丝分裂每15分钟发生一次。具体而言，细胞周期进程或Rab5活性将通过已建立的方法进行调节，并且它们对ER形态的影响通过GFP标记的ER标志物的时移共聚焦成像来评估。本研究的主要目的是：（1）确定果蝇早期胚胎中细胞周期蛋白在有丝分裂内质网重组中的作用。(2)研究Rab5活性的调节如何影响有丝分裂ER重组。 公共卫生相关性：由于ER在细胞功能中的基本作用，该提议与主要的慢性人类疾病如2型糖尿病、自闭症和阿尔茨海默病具有广泛和显著的相关性。完成拟议的实验将产生一个基本的分子理解ER形态是如何在细胞周期的调节。这一特殊的知识将有助于开发治疗遗传性痉挛性截瘫等疾病的疗法。

DESCRIPTION (provided by applicant): Major cellular functions such as protein synthesis and folding, lipid synthesis, intracellular calcium storage, and nuclear transport of macromolecules all depend on the endoplasmic reticulum (ER). Failures in ER structure or function have been linked to a host of chronic diseases such as type-2 diabetes and autism, and neurodegenerative diseases such as hereditary spastic paraplegia (HSP) and Alzheimer's disease. During mitosis, ER morphology changes dramatically, a phenomenon necessary for proper membrane partitioning and nuclear membrane formation. Relatively little is known about how mitotic ER changes occur and how they are regulated, or which molecular mechanisms are responsible for these changes. Mitotic cyclin:Cdk kinase complexes are master regulators of nuclear and cytoskeletal dynamics during cell division, yet their involvement in mitotic ER reorganization is unknown. Additionally, since members of the Ras superfamily of small GTPases control changes during mitosis, they are likely to drive mitotic ER dynamics. Indeed, the Rab5 GTPase was recently found to have a role in mitotic ER structure independent of its endocytic role. Therefore, exploring how these proteins affect ER morphology is a key issue to be addressed. The goal of this project is to define the regulation of ER reorganization during mitosis by mitotic cyclin:Cdk and to define a molecular pathway that coordinates mitotic ER reorganization with Rab5 GTPase activity. These processes will be studied in detail in the embryo of the model organism, Drosophila melanogaster. The early Drosophila embryo is ideal for studying mitosis due to its rapid, abbreviated cell cycle, with initial rounds of mitosis occurring every ~15 minutes. Specifically, cell cycle progression or Rab5 activity will be modulated through established methods, and their effects on ER morphology assessed via timelapse confocal imaging of GFP-tagged ER markers. The aims of the proposal are as follows: (1) Determine the role of mitotic cyclins on mitotic ER reorganization in the early Drosophila embryo. (2) Investigate how modulation of Rab5 activity affects mitotic ER reorganization. PUBLIC HEALTH RELEVANCE: This proposal has broad and significant relevance to major chronic human diseases like type-2 diabetes, autism, and Alzheimer's disease, due to the fundamental roles of the ER in cellular function. Completion of the proposed experiments would yield a basic molecular understanding of how ER morphology is regulated during the cell cycle. This particular knowledge would contribute to the development of therapies for diseases like hereditary spastic paraplegia.