Centrosome biogenesis and copy number control

项目摘要 我们实验室的长期目标是了解控制中心粒复制和 确保细胞分裂过程中基因组的准确分布。中心粒构成了中心体的核心， 它们组织了大多数动物细胞的间期微管细胞骨架，形成了有丝分裂的极点 纺锤形。中心粒也可以被修饰以形成基本体，这是纤毛形成和发挥的模板 在细胞信号、液体运动和运动中起中心作用。来协调这些不同的细胞 加工过程中，中心粒拷贝数必须得到精确控制。细胞以两个中心粒开始G1期， 它们在S/G2期被复制，然后在 有丝分裂。我们和其他人已经证明，额外的中心粒会导致足以驱动细胞分裂的误差 恶变。了解细胞实现每周期一次复制的机制 因此，中心粒的数量是与人类健康密切相关的一个重要的基本问题。 虽然在理解中心粒的组成方面已经取得了重大进展，但仍不清楚。 中心粒形成的哪些具体步骤由酶调节蛋白Polo-like-kinase4(Plk4)控制。 同样不清楚的是，一个关键的调控步骤，即所谓的中心粒到中心体的转换(CCC)， 通过使新的中心粒获得复制能力来维持中心粒的动态平衡。 我们提议的研究试图利用我们对中心粒的关键相互作用和贡献者的识别。 形成以阐明控制中心粒组装的分子机制。我们将考察三个 中心粒生物发生控制的独立成分：Plk4表达的翻译调控 Plk4对特定底物的磷酸化在中心粒组装中的影响以及一个新的功能 CCC所需的组件。目标1将定义一对保守的上游开放阅读框如何在 Plk4的mRNA调控Plk4表达的关键方面。目标2将机械地剖析一个关键的 我们在STIL上发现的Plk4磷酸化位点控制着中心粒的组装。最后，目标3将定义如何 新的中心粒蛋白PPP1R35具有促进CCC的功能。了解中心粒组装是如何进行的 调控将揭示细胞器动态平衡的基本原理，并提供对分子的洞察 人类疾病的基础是中心粒功能障碍。

Project Summary The long-term goal of our lab is to understand the molecular mechanisms that control centriole duplication and ensure the accurate distribution of the genome during cell division. Centrioles form the core of centrosomes, which organize the interphase microtubule cytoskeleton of most animal cells and form the poles of the mitotic spindle. Centrioles can also be modified to form basal bodies, which template the formation of cilia and play central roles in cellular signaling, fluid movement, and locomotion. To coordinate these diverse cellular processes, centriole copy number must be precisely controlled. Cells begin G1 phase with two centrioles, which are duplicated during S/G2 phase and are then carefully partitioned into both daughter cells during mitosis. We and others have shown that extra centrioles cause cell division errors that are sufficient to drive malignant transformation. Understanding the mechanism by which cells achieve the once per cycle duplication of the centrioles is, therefore, an important fundamental question of considerable relevance to human health. Although significant progress has been made in understanding the composition of centrioles, it remains unclear which specific steps in centriole formation are controlled by the enzymatic regulator Polo-like-kinase 4 (PLK4). Equally unclear is how a critical regulatory step, termed the ‘centriole-to-centrosome conversion’ (CCC), functions to maintain centriole homeostasis by enabling new centrioles to acquire competence for duplication. Our proposed research seeks to capitalize on our identification of key interactions and contributors to centriole formation to elucidate molecular mechanisms that control centriole assembly. We will examine three independent components of centriole biogenesis control: the translational regulation of PLK4 expression, the impact of PLK4 phosphorylation of specific substrates in centriole assembly, and the function of a new component required for the CCC. Aim 1 will define how a pair of conserved upstream open reading frames in the PLK4 mRNA regulate critical aspects of PLK4 expression. Aim 2 will mechanistically dissect how a critical PLK4 phosphorylation site we identified on STIL controls centriole assembly. Finally, Aim 3 will define how a new centriole protein, PPP1R35, functions to promote the CCC. Understanding how centriole assembly is regulated will reveal fundamental principles of organelle homeostasis and provide insight into the molecular basis of human diseases caused by centriole dysfunction.