Proteolytic Control Of Yeast Cell Type

酵母细胞类型的蛋白水解控制

• 批准号: 7033167
• 负责人: Jeffrey Laney
• 金额: $ 28.47万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-20 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7033167
• 关键词: Saccharomyces cerevisiae; biological signal transduction; cell type; enzyme mechanism; fungal genetics; fungal proteins; gene expression; gene induction /repression; genetic promoter element; intermolecular interaction; ligase; microorganism culture; protein binding; protein degradation; protein structure function; proteolysis; transcription factor; ubiquitin

DESCRIPTION (provided by applicant): Due to its involvement in the control of a wide array of cellular processes, substrate-selective protein degradation has emerged as a major cell regulatory mechanism. Permanent or transient metabolic instability is a property of a number of different regulatory proteins, including transcription factors, signaling molecules, cell cycle regulators, apoptotic factors, proto-oncogene products, and tumor suppressor proteins. In eukaryotes, these regulatory proteins are targeted for destruction by a complex enzymatic system that involves their post-translational modification by ubiquitin and their subsequent degradation by a large multi- subunit protease called the proteasome. Previously, we determined that the rapid ubiquitin-dependent degradation of a master regulatory transcription factor, which is a key determinant of cellular identity in the yeast Saccharomyces cerevisiae, is required for yeast cells to change their phenotype during a normal differentiation event. To further our understanding of how a cell exploits the process of ubiquitin-mediated proteolysis to change patterns of gene expression and switch between alternative phenotypic states, we propose to characterize the biological impact and the molecular mechanisms of the rapid proteolysis of two different yeast cell type-specific transcription factors, alpha1 and alpha2. Our overall objective is to understand the mechanisms by which the rapid degradation of these multiple master regulatory transcription factors is synthesized into a single phenotypically defined developmental transition in yeast. Specifically, we will (1) characterize the interplay between the proteolysis of alpha2, the dynamics of alpha2 binding to target gene promoters and alpha2-mediated repression in vivo; (2) identify the molecular features of the cell type regulator alpha1 that govern its stability; and (3) determine the enzymatic pathways and cellular machinery that cause alpha1 to be short-lived. These studies, which characterize phenotypic switching events in an experimentally amenable model system, will provide information for understanding not only the differentiation processes that underlie normal cell growth and development, but also the pathological situations caused by defects in switching from a state of proliferation to the fully differentiated, non-proliferating cell-type.

描述（由申请人提供）：由于它参与了多种细胞过程的控制，底物选择蛋白降解已成为主要的细胞调节机制。永久性或瞬态代谢不稳定性是许多不同调节蛋白的特性，包括转录因子，信号分子，细胞周期调节剂，凋亡因子，原始癌基因产物和肿瘤抑制蛋白。在真核生物中，这些调节蛋白的目标是通过复杂的酶系统破坏，涉及泛素的翻译后修饰及其随后通过称为蛋白酶体的大型多亚基蛋白酶降解。以前，我们确定酵母细胞在正常差异事件中需要改变酵母菌细胞在酵母糖含量的酿酒酵母中快速泛素依赖性降解，这是酵母菌细胞在酵母菌酿酒酵母中的关键决定因素。为了进一步了解细胞如何利用泛素介导的蛋白水解的过程，以改变基因表达的模式，并在替代表型态之间切换，我们建议表征两种不同Yeast Yeast细胞类型的转录因子，Alpha1和Alpha2的生物学影响和快速蛋白水解的生物学影响和分子机制。我们的总体目标是了解这些多个主调节转录因子的快速降解的机制被合成为酵母中单个表型定义的发育过渡。具体而言，我们将（1）表征α2蛋白水解之间的相互作用，α2与靶基因启动子的动力学和体内α2介导的抑制作用； （2）确定控制其稳定性的细胞类型调节剂α1的分子特征； （3）确定导致α1短暂寿命的酶促途径和细胞机制。这些研究表征了实验性符合模型系统中表型切换事件的特征，它将提供信息，不仅是理解正常细胞生长和发育构成的分化过程，而且还可以理解由从增殖状态到完全差异化的，非增殖的，非增殖的细胞类型的缺陷引起的病理状况。