CYTOSOLIC-VESICLE-VACUOLAR PROTEIN DEGRADATION PATHWAY

细胞质-囊泡-液泡蛋白降解途径

• 批准号: 6795603
• 负责人: HUI-LING CHIANG
• 金额: $ 27.95万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6795603
• 关键词: Saccharomyces cerevisiae; adenosinetriphosphatase; binding proteins; cytoplasm; cytoskeletal proteins; fructose biphosphatase; gene expression; microscopy; peptidylprolyl isomerase; protein degradation; protein transport; vesicle /vacuole

DESCRIPTION (provided by applicant): Lysosomes are responsible for the degradation of long-lived cytosolic proteins via a chaperone mediated autophagy pathway or by a macroautophagy pathway. The lysosomal protein LAMP-2 is involved in the autophagy degradation pathway. When this gene was deleted in mice, cardiomyopathy resembling Danon's Disease was found. Furthermore, autophagy may play some role in cancer, since the cancer suppressor gene beclin 1 is homologous to the autophagy gene APG6. Therefore, defects in lysosomal degradation may lead to abnormal cell growth and metabolic disorders. The long-term goals of our research are to study how cytosolic proteins are targeted to lysosomes/vacuoles for degradation. We have utilized the key gluconeogenic enzyme fructose-1,6-bisphosphatase (FBPase) as a marker protein to study this pathway in S. cerevisiae. FBPase is targeted from the cytosol to a novel class of vesicle (Vid vesicle) when S. cerevisiae are shifted from low glucose media to high glucose media. FBPase is then targeted to the vacuole for degradation. VID genes regulate the FBPase degradation pathway and are classified into two categories. Class A VID genes regulate FBPase import into Vid vesicles, while Class B VID genes control the fusion of Vid vesicles with the vacuole. We propose to (1) study how Class A genes regulate FBPase import. We will focus on VID21, VID27 and VID28, since their precise roles in FBPase import have not been determined and their gene products have not been characterized. (2) We will examine how FBPase is imported into Vid vesicles. We hypothesize that FBPase import is mediated by a transport machinery on Vid vesicles. We propose to purify and identify Vid vesicle proteins that interact with FBPase and test their functions in the import process. (3) Finally, we will determine whether a SNARE mediated fusion machinery is involved in the fusion of Vid vesicles with the vacuole. We will also determine how Class B genes regulate the fusion process.

描述(申请人提供)：溶酶体负责通过伴侣介导的自噬途径或通过大的自噬途径降解长寿的细胞质蛋白。溶酶体蛋白LAMP-2参与自噬降解途径。当该基因在小鼠身上缺失时，发现了类似达农氏病的心肌病。此外，自噬可能在癌症中起到一定作用，因为癌症抑制基因Beclin 1与自噬基因APG6同源。因此，溶酶体降解缺陷可能导致细胞生长异常和代谢紊乱。 我们研究的长期目标是研究胞质蛋白是如何针对溶酶体/空泡进行降解的。我们利用关键的糖异生酶果糖-1，6-二磷酸酶(FBPase)作为标记蛋白来研究酿酒酵母中的这一途径。当酿酒酵母从低糖培养基转到高糖培养基时，FBPase被定位于一种新的囊泡(VID囊泡)。然后，FBPase被定位到液泡进行降解。VID基因调控FBPase降解途径，分为两类。A类VID基因调控FBPase进入VID囊泡，而B类VID基因控制VID囊泡与液泡的融合。我们建议(1)研究A类基因如何调控FBPase的导入。我们将重点关注VID21、VID27和VID28，因为它们在FBPase导入中的确切作用还没有确定，它们的基因产物也没有被鉴定。(2)我们将研究FBPase是如何导入VID囊泡的。我们假设FBPase的导入是由VID囊泡上的运输机械介导的。我们建议纯化和鉴定与FBPase相互作用的VID囊泡蛋白，并测试它们在进口过程中的功能。(3)最后，我们将确定是否有陷阱介导的融合机制参与了VV囊泡与液泡的融合。我们还将确定B类基因如何调节融合过程。