Selective Autophagic Degradation of Peroxisomes in Yeast

酵母中过氧化物酶体的选择性自噬降解

• 批准号: 6442015
• 负责人: James Michael Cregg
• 金额: $ 3.63万
• 依托单位: KECK GRADUATE INST OF APPLIED LIFE SCIS
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-30 至 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6442015
• 关键词: Poland; autophagy; cooperative study; electron microscopy; fluorescence microscopy; fungal genetics; fungal proteins; gene expression; gene mutation; genetic screening; immunocytochemistry; immunoprecipitation; lysosomes; method development; mutant; nucleic acid sequence; peroxisome; protein degradation; protein localization; protein sequence; protein structure function; vesicle /vacuole; yeast two hybrid system; yeasts

DESCRIPTION (provided by applicant) The primary degradative compartment in the cell is the lysosome (or its equivalent in plants and yeasts, the vacuole). Although cells have evolved multiple mechanisms to deliver cellular components to the lysosome, the major route is via a set of processes collectively termed autophagy. Frequent targets of these processes are peroxisomes, organelles that contain essential oxidative enzymes. The number, size, and enzymatic content of peroxisomes change rapidly in response to a cell's metabolic needs, and when peroxisomes of a certain metabolic type are no longer useful, they are selectively removed by autophagic processes. The goal of this project is to understand the molecular mechanisms that control autophagy. A genetic approach has been initiated using the yeast Pichia pastoris as a model system. This yeast has large numerous peroxisomes when cultured on methanol, which are selectively autophagized upon transfer to either glucose or ethanol. During the period of our previous FIRCA, we succeeded in isolating and characterizing P. pastoris mutants in six different genes that are defective in autophagic peroxisome degradation in response to glucose. Four of these PDG genes were isolated, and DNA sequencing results indicate that all four encode novel proteins of unknown function. The specific aims of this continuing FIRCA proposal are: (1) to characterize the four PDG proteins by determining their subcellular location and searching for other genes whose products interact with them; (2) to determine what other vacuolar sorting pathways are affected by mutations in each gene; and (3) to develop and utilize novel screens and selection methods for the isolation of mutants in new PDG genes. Results of these studies will provide important insights into autophagic mechanisms.

描述（由申请人提供） 细胞中的主要降解区室是溶酶体（或其 相当于植物和酵母中的液泡）。虽然细胞已经进化了 将细胞成分传递至溶酶体的多种机制 途径是通过一组统称为自噬的过程。频繁目标 这些过程中的一个是过氧化物酶体，即含有必需氧化物质的细胞器 酶。过氧化物酶体的数量、大小和酶含量迅速变化 响应细胞的代谢需求，并且当特定的过氧化物酶体 代谢型不再有用，它们被自噬选择性地去除 流程。 该项目的目标是了解控制的分子机制 自噬。已经使用毕赤酵母启动了遗传方法 毕赤酵母作为模型系统。当这种酵母有大量的过氧化物酶体时 在甲醇上培养，转移后选择性自噬 葡萄糖或乙醇。在上一次 FIRCA 期间，我们 成功地分离和表征了六种不同的巴斯德毕赤酵母突变体 自噬过氧化物酶体降解反应中存在缺陷的基因 葡萄糖。分离出其中四个PDG基因，并进行DNA测序结果 表明所有四种都编码功能未知的新蛋白质。 这项持续的 FIRCA 提案的具体目标是：(1) 描述 通过确定四种 PDG 蛋白的亚细胞位置并搜索 对于其产物与其相互作用的其他基因； (2) 确定还有哪些 液泡分选途径受到每个基因突变的影响； (3) 至 开发和利用新颖的筛选和选择方法来分离 新PDG基因的突变体。这些研究的结果将提供重要的 对自噬机制的见解。