Regulation of polarized cell growth by GTPases

GTPases 对极化细胞生长的调节

• 批准号: 7015774
• 负责人: Hay-Oak Park
• 金额: $ 31.22万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7015774
• 关键词: Saccharomyces cerevisiae; actins; cell cycle; cell growth regulation; cellular polarity; cytoskeleton; enzyme activity; enzyme complex; fluorescence spectrometry; fungal genetics; gene expression; gene interaction; genetic regulation; guanosinetriphosphatase activating protein; guanosinetriphosphatases; hydrolysis; macromolecule; molecular assembly /self assembly; molecular genetics; protein structure function

DESCRIPTION (provided by applicant): Polarity establishment and oriented cell divisions are central to the development of many organisms. Cells of the budding yeast S. cerevisiae exhibit two distinct patterns of budding depending on their cell type, reflecting genetic programming of cell polarization. It is believed that a cell responds to a cell-type-specific cortical marker, which is associated with the plasma membrane. All cell types use a common downstream pathway for polarity establishment, which involves the Ras and Rho family GTPases Rsr1/Bud1 and Cdc42. Despite current knowledge of many proteins involved in budding, how polarity is established toward a spatially defined site is largely unknown. This proposal focuses on how a macromolecular complex that specifies a specific bud site is assembled, and how polarity establishment is controlled in a spatial and temporal manner. Based on genetic and biochemical data, it is hypothesized that GTPases regulate various steps of polarity establishment. To test the hypothesis, multi-directional approaches will be undertaken using molecular genetic, biochemical, and cell biological methods. Specific aims are to understand: 1) How a macromolecular complex that specifies a bud site is assembled and how the transient spatial information is inherited in every cell division cycle; 2) how Bud2 and Bud5, regulators for Rsr1, interact with a distinct spatial landmark in each cell type, and whether the interactions regulate their activity; and 3) how Rsr1 regulates Cdc24, a GEF for Cdc42, and assembly of the Cdc42 complex at the bud site. Although polarity establishment is a complex problem, the facile genetics of yeast provides the unique opportunity to study a signaling pathway leading to polarized organization of the actin cytoskeleton at the molecular level. Development of mammalian cells also requires continual changes in the actin cytoskeleton in response to internal and external signals as seen during wound healing or chemotaxis during infection. Understanding the molecular mechanism underlying polarity establishment in yeast is expected to provide the molecular basis of actin cytoskeleton organization in mammalian cells. Given the structural and functional conservation of GTPases and their regulators in eukaryotes, knowledge gained will also allow an insight into novel mechanisms for these critical regulators of normal development, which is expected to be relevant to most eukaryotes including humans.

描述（由申请人提供）：极性建立和定向细胞分裂是许多生物体发育的核心。芽殖酵母S.酿酒酵母根据其细胞类型表现出两种不同的出芽模式，反映了细胞极化的遗传编程。据信，细胞响应于与质膜相关的细胞类型特异性皮质标记物。所有细胞类型使用共同的下游途径来建立极性，其涉及Ras和Rho家族GTP酶Rsr 1/Bud 1和Cdc 42。尽管目前的知识，许多蛋白质参与出芽，极性是如何建立对一个空间定义的网站在很大程度上是未知的。这个建议的重点是如何一个大分子复合物，指定一个特定的芽网站组装，以及如何极性建立控制在空间和时间的方式。基于遗传和生物化学数据，假设GTP酶调节极性建立的各个步骤。为了验证这一假设，将采用分子遗传学、生物化学和细胞生物学方法进行多方向的研究。具体目标是了解：1）指定芽位点的大分子复合物是如何组装的，以及瞬时空间信息如何在每个细胞分裂周期中遗传; 2）Rsr 1的调节因子Bud 2和Bud 5如何与每种细胞类型中不同的空间标志相互作用，以及这种相互作用是否调节它们的活性; 3）Rsr 1如何调节Cdc 24、Cdc 42的GEF以及Cdc 42复合物在芽位点的组装。虽然极性的建立是一个复杂的问题，但酵母的简易遗传学提供了独特的机会来研究导致肌动蛋白细胞骨架在分子水平上极化组织的信号通路。哺乳动物细胞的发育还需要肌动蛋白细胞骨架响应于内部和外部信号的持续变化，如在伤口愈合或感染期间的趋化性期间所见。了解在酵母中极性建立的分子机制有望为哺乳动物细胞中肌动蛋白细胞骨架组织提供分子基础。鉴于GTP酶及其调节剂在真核生物中的结构和功能保守性，所获得的知识还将允许深入了解这些正常发育的关键调节剂的新机制，预计这与包括人类在内的大多数真核生物相关。