Spatial and temporal regulation of polarity establishment in budding yeast

芽殖酵母极性建立的时空调控

• 批准号: 9064778
• 负责人: Hay-Oak Park
• 金额: $ 29.65万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-07 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9064778
• 关键词: Alpha Cell; Animals; Biochemical; Biological; Biological Assay; Cell Nucleus; Cell Polarity; Cell division; Cell physiology; Cells; Computer Simulation; Cues; Data; Defect; Development; Diploidy; Disease; Embryo; Embryonic Development; Epithelial; Eukaryota; Eukaryotic Cell; Event; Exhibits; Family; Feedback; Fibroblasts; G1 Phase; GTPase-Activating Proteins; Genetic; Goals; Growth; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Haploid Cells; Haploidy; Health; Human; Immune response; In Vitro; Lead; Link; Malignant Neoplasms; Mammals; Methods; Modeling; Molecular; Movement; Neoplasm Metastasis; Pathway interactions; Pattern; Process; Proteins; Quantitative Microscopy; Regulation; Research; Role; Saccharomyces cerevisiae; Saccharomycetales; Series; Site; System; Temperature; Testing; Tissues; Work; Wound Healing; Yeasts; base; cell motility; cell type; in vitro Assay; in vivo; insight; interdisciplinary approach; live cell imaging; macromolecular assembly; mutant; novel; programs; response; stoichiometry; tumor

 DESCRIPTION (provided by applicant): Establishment of cell polarity is critical for a variety of cellular processes including proliferation and cell movement, as seen in developing embryos, wound healing, and bud formation during yeast growth. Loss of cell polarity is, therefore, implicated in several disease processes, for example, in epithelial tumors. The Cdc42 GTPase is a central regulator of cell polarity in both yeast and animals and is also a critical regulator f metastasis. Although cell polarization occurs along a single axis that is generally determined by a spatial cue, a large number of recent studies have focused on the mechanisms of polarity establishment in the absence of spatial cues. Thus, how a specific direction of cell polarization is determined and how the process is regulated in a spatial and temporal manner are largely unknown. The proposed work capitalizes on the tractable yeast system to elucidate the mechanisms underlying spatial cue-directed cell polarization. Cells of the budding yeast undergo polarized growth in two spatially programmed patterns. We recently discovered that Cdc42 is activated in two temporal steps in the G1 phase. The first step depends on Bud3, a cortical protein marking the cell division site in haploids, while subsequent activation depends on Cdc24, which has heretofore been the sole GDP-GTP exchange factor (GEF) for Cdc42. This finding led us to hypothesize that sequential activation of Cdc42 in the G1 phase is fundamental to appropriate recognition and readout of cell polarity cues in haploid budding yeast. Aim 1 seeks to investigate how spatial landmarks and the Rsr1 GTPase module regulate activation of Cdc42 in early G1. Our genetic and biochemical data suggest an unexpected role of Cdc42 in establishment of a proper bud site. Thus, Aim 2 seeks the mechanism of action of Cdc42 and its regulators in establishment of cell polarity at a proper bud site. Finally, Aim 3 explores the molecular basis of the cell-type-specific budding pattern and investigates the assembly of the cortical markers that determines the orientation of the polarity axis. This research plan will employ biochemical methods and quantitative microscopy, as well as computational modeling. This study is expected to establish how sequential activation of Cdc42 governs recognition of spatial landmarks and execution of polarity establishment. Given the ubiquitous importance of Cdc42 in cell polarity events from yeast to humans, findings from this work will be relevant to spatial cue-directed cell polarization in higher eukaryotes, including mammals.

 描述（由申请人提供）：细胞极性的建立对于包括增殖和细胞运动在内的多种细胞过程至关重要，如在酵母生长过程中胚胎发育、伤口愈合和芽形成中所见。因此，细胞极性的丧失与多种疾病过程有关，例如上皮肿瘤。 Cdc42 GTPase 是酵母和动物细胞极性的中心调节因子，也是转移的关键调节因子。尽管细胞极化沿着通常由空间线索决定的单轴发生，但最近的大量研究都集中在没有空间线索的情况下极性建立的机制。因此，如何确定细胞极化的特定方向以及如何以空间和时间方式调节该过程在很大程度上是未知的。拟议的工作利用易处理的酵母系统来阐明空间线索定向细胞极化的机制。芽殖酵母的细胞以两种空间编程模式经历极化生长。我们最近发现 Cdc42 在 G1 阶段分两个时间步骤被激活。第一步取决于 Bud3，这是一种标记单倍体细胞分裂位点的皮质蛋白，而后续激活取决于 Cdc24，迄今为止，Cdc42 一直是 Cdc42 的唯一 GDP-GTP 交换因子 (GEF)。这一发现使我们推测，G1 期 Cdc42 的连续激活对于单倍体芽殖酵母中细胞极性线索的适当识别和读出至关重要。目标 1 旨在研究空间标志和 Rsr1 GTPase 模块如何调节 G1 早期 Cdc42 的激活。我们的遗传和生化数据表明 Cdc42 在建立适当的芽位点方面发挥着意想不到的作用。因此，目标 2 寻找 Cdc42 及其调节剂在适当芽位点建立细胞极性的作用机制。最后，目标 3 探索了细胞类型特异性出芽模式的分子基础，并研究了决定极性轴方向的皮质标记的组装。该研究计划将采用生化方法和定量显微镜以及计算模型。这项研究预计将确定 Cdc42 的顺序激活如何控制空间地标的识别和极性建立的执行。鉴于 Cdc42 在从酵母到人类的细胞极性事件中无处不在的重要性，这项工作的发现将与包括哺乳动物在内的高等真核生物中空间线索导向的细胞极化相关。