Evolutionary adaptation and spatial organization of signaling in the Mitotic Exit Network

有丝分裂出口网络中信号的进化适应和空间组织

• 批准号: 10331332
• 负责人: Xiaoxue Zhou
• 金额: $ 10万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10331332
• 关键词: Address; Anaphase; Binding; Binding Sites; Biological Models; Case Study; Cell Cycle Progression; Cell Cycle Regulation; Cell Nucleolus; Cell division; Cell membrane; Cell physiology; Cells; Centrosome; Complex; Development; Dimerization; Disease; Ensure; Eukaryota; Evolution; Foundations; Functional disorder; Future; Guanosine Triphosphate Phosphohydrolases; Homologous Gene; Human; Hybrids; Knock-out; Label; Life; Light; Location; Logic; Malignant Neoplasms; Mammalian Cell; Mammals; Mediating; Meiosis; Mentors; Mitochondria; Mitogen-Activated Protein Kinases; Mitosis; Mitotic; Modeling; Nucleotides; Organism; Pathway interactions; Phase; Phosphoric Monoester Hydrolases; Phosphotransferases; Positioning Attribute; Process; Protein phosphatase; Proteins; Quantitative Microscopy; Regulation; Research; Research Personnel; Saccharomycetales; Signal Pathway; Signal Transduction; Surface; System; Testing; Training; Work; Yeasts; base; career; comparative; experimental study; information processing; inhibitor; insight; mutant; optogenetics; pressure; prevent; scaffold; spindle pole body; tool

Project Summary Sensing and processing information through signaling cascades is an essential part of cellular life. A few signaling cascades such as the MAP kinase and Hippo pathways are ubiquitous among eukaryotes yet perform different functions across organisms. Although these pathways are well-studied, how they evolve to take on new functions and adapt to new inputs remains poorly understood. The Mitotic Exit Network (MEN), a Ras-like GTPase signaling cascade and yeast homolog of the Hippo pathway, provides a unique opportunity to study this question. In the MEN, the same core signaling components operate in distinct manners under different developmental trajectories. During yeast mitosis which occurs through an asymmetric cell division called budding, the MEN is scaffolded onto the spindle pole bodies (SPB, the yeast equivalent of centrosomes) and responds to spindle position through its GTPase Tem1. During meiosis, where budding is suppressed and thus no need to sense spindle position, MEN signaling is no longer organized at the SPBs, and it is unclear whether Tem1 is still required for MEN activation and what signal it may respond to. To understand the adaptation of the MEN under distinct cellular contexts, this proposal will test the hypothesis that this adaptation is enabled partially by different activation mechanisms of the MEN kinase Cdc15, the effector kinase of Tem1, between mitosis and meiosis (Aim 1). In contrast to the drastic change in spatial organization of the MEN core components between mitosis and meiosis, the effector protein of the MEN, the phosphatase Cdc14, remains sequestered in the nucleolus prior to activation both in mitosis and meiosis. In fact, this nucleolar localization of Cdc14 is conserved from yeast to human. Sequestration of Cdc14 in the nucleolus could function either 1) to ensure tight inhibition of Cdc14’s phosphatase activity prior to activation or 2) to localize Cdc14 to dephosphorylate specific substrates in the nucleolus. To uncover the selection pressure that maintains this conserved nucleolar localization of Cdc14, this proposal will examine these two hypotheses by sequestering Cdc14 elsewhere in the cell and characterize the consequences first in yeast and then in mammalian cells (Aim 2). The experiments within both aims will be initiated during the K99 phase which also includes training of the candidate on new experimental systems such as yeast meiosis and mammalian cells, as well as the development and implementation of quantitative microscopy, proximity labeling and optogenetics. Furthermore, the candidate has assembled an outstanding mentor team to both advise her scientifically to facilitate progress of the project and prepare her for the transition to an independent investigator. Together, this proposal will create a strong foundation for an independent research career in understanding the evolution/adaptation and spatial organization of cellular signaling.

项目概要 通过信号级联感知和处理信息是细胞生命的重要组成部分。几个 MAP 激酶和 Hippo 通路等信号级联在真核生物中普遍存在 在生物体中执行不同的功能。尽管这些途径已得到充分研究，但它们是如何进化的 承担新职能和适应新投入仍然知之甚少。有丝分裂退出网络 (MEN) Ras 样 GTPase 信号级联和 Hippo 途径的酵母同源物，提供了独特的机会 研究这个问题。在 MEN 中，相同的核心信令组件在不同的方式下运行 不同的发展轨迹。在通过不对称细胞分裂发生的酵母有丝分裂期间 称为出芽，MEN 被搭建在纺锤体极体上（SPB，相当于酵母的中心体） 并通过其 GTPase Tem1 响应纺锤体位置。在减数分裂期间，出芽受到抑制， 因此不需要感知纺锤体位置，MEN 信号不再在 SPB 上组织，目前还不清楚 MEN 激活是否仍需要 Tem1 以及它可能响应什么信号。要了解 MEN 在不同的细胞环境下的适应，该提案将测试这种适应的假设 部分是由 MEN 激酶 Cdc15（Tem1 的效应激酶）的不同激活机制实现的， 有丝分裂和减数分裂之间（目标 1）。与 MEN 核心空间组织的巨大变化形成鲜明对比 有丝分裂和减数分裂之间的组成部分，MEN 的效应蛋白，即磷酸酶 Cdc14，仍然存在 在有丝分裂和减数分裂中激活之前被隔离在核仁中。事实上，这种核仁定位 Cdc14 从酵母到人类都是保守的。 Cdc14 隔离在核仁中可以发挥以下任一作用： 1) 确保在激活之前严格抑制 Cdc14 的磷酸酶活性或 2) 将 Cdc14 定位到 使核仁中的特定底物去磷酸化。揭示维持这一现状的选择压力 由于 Cdc14 的保守核仁定位，该提案将通过隔离来检验这两个假设 Cdc14 在细胞的其他地方，首先在酵母中，然后在哺乳动物细胞中表征其后果 （目标 2）。这两个目标的实验将在 K99 阶段启动，其中还包括培训 新实验系统的候选人，例如酵母减数分裂和哺乳动物细胞，以及 定量显微镜、邻近标记和光遗传学的开发和实施。此外， 候选人组建了一支优秀的导师团队，为她提供科学的建议，以促进进步 项目并为她过渡为独立调查员做好准备。总之，该提案将 为了解进化/适应和理解进化/适应的独立研究生涯奠定坚实的基础 细胞信号传导的空间组织。