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: 9258144
• 负责人: Hay-Oak Park
• 金额: $ 16.67万
• 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/9258144
• 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（通过应用提供）：细胞极性的建立对于多种细胞过程至关重要，包括增殖和细胞运动，如在酵母生长过程中发育，伤口愈合和芽形成中所见。因此，细胞极性的丧失与几种疾病过程有关，例如在上皮肿瘤中。 Cdc42 GTPase是酵母和动物中细胞极性的中心调节剂，尽管细胞极化沿单个轴通常由一个通常由空间提示确定的细胞极化发生，但在缺乏空间线索的情况下，大量最近的研究集中在极性建立的机理上。这是如何确定细胞极化的特定方向，以及如何以空间和临时方式调节过程。拟议的工作资源在可牵引的酵母系统上阐明了空间提示指导的细胞极化的机制。发芽酵母的细胞在两个空间编程的模式下经历了极化的生长。我们最近发现，在G1阶段，CDC42在两个临时步骤中被激活。第一步取决于Bud3，这是一种在单倍体中标记细胞分裂位点的皮质蛋白，而随后的激活取决于Cdc24，迄今为止，它是Cdc42的唯一GDP-GTP交换因子（GEF）。这一发现使我们假设在G1相中，Cdc42的顺序激活是对单倍体芽酵母中细胞极性提示的适当识别和读数的基础。 AIM 1试图研究空间地标和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在建立适当的芽位中的意外作用。这是AIM 2寻求CDC42及其调节剂在适当的芽部位建立细胞极性方面的作用机理。最后，AIM 3探讨了细胞型特异性芽模式的分子基础，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建模。预计这项研究将确定CDC42的顺序激活如何控制对空间标志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的无处不在，这项工作的发现将与包括哺乳动物在内的较高真核生物中的空间提示指导的细胞极化有关。