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的分子机制， 确保细胞分裂过程中基因组的准确分布。中心粒形成中心体的核心， 它组织大多数动物细胞的间期微管细胞骨架，并形成有丝分裂的两极。 纺锤体。中心粒也可以被修饰形成基底体，基底体作为纤毛和plays形成的模板 在细胞信号传导、流体运动和运动中的核心作用。为了协调这些不同的细胞 过程中，中心粒拷贝数必须精确控制。细胞开始具有两个中心粒的G1期， 它们在S/G2期复制，然后在S/G2期被小心地分配到两个子细胞中。 分裂。我们和其他人已经表明，额外的中心粒导致细胞分裂错误，足以驱动 恶性转化了解细胞实现每周期一次复制的机制 因此，中心粒是与人类健康相当相关的重要基本问题。 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 中心粒形成中的特定步骤由酶调节剂Polo样激酶4（PLK4）控制。 同样不清楚的是，一个被称为"中心粒到中心体转换"（CCC）的关键调控步骤， 通过使新的中心粒获得复制能力来维持中心粒的稳态。 我们提出的研究旨在利用我们对中心粒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。我们将研究三个 中心粒生物发生控制的独立成分：PLK4表达的翻译调节， PLK4磷酸化对中心粒组装中特定底物的影响，以及一种新的 这是CCC所需要的。目的1将定义一对保守的上游开放阅读框架如何在 PLK4 mRNA调节PLK4表达关键方面。目标2将机械地剖析关键的 我们在STIL上鉴定的PLK4磷酸化位点控制中心粒组装。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 调节将揭示细胞器稳态的基本原则，并提供对分子生物学的深入了解。 中心粒功能障碍引起的人类疾病的基础。

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.