A New Cellular Protein Degradation Pathway for Lysosome Homeostasis and Remodeling

溶酶体稳态和重塑的新细胞蛋白降解途径

• 批准号: RGPIN-2017-06652
• 负责人: Brett, Christopher
• 金额: $ 2.04万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712290
• 关键词: New; Cellular; Protein; Degradation; Pathway

Although they may not be aware, everyone recycles to sustain life on earth at least from the perspective of a cell biologist. This is because all eukaryotic cells, including those that constitute you and I, rely on organelles called lysosomes to recycle biomaterials. Lysosomes recycle unneeded or damaged cellular components, and clear extracellular debris or pathogens by converting them into an important source of nutrients. As such, lysosome activity is needed to sustain metabolism when cells are starved, and to remove toxic biomaterials that accumulate in cells as they age. To function, these dynamic organelles rely on nutrient transporters to return products of catabolism (amino acids, lipids, nucleic acids) to the cell for reuse. But little is know about these transporters including how they are regulated or degraded. Until recently, when we discovered a new process in the model organism Saccharomyces cerevisiae called the IntraLumenal Fragment (ILF) pathway that selectively degrades lysosome transporters when damaged, in response to substrate levels, or by TOR-signaling an important mediator of cellular aging. This process selectively sorts transporters into an area of membrane that is internalized and degraded by lumenal hydrolases upon homotypic lysosome membrane fusion. But many open questions must be answered to comprehensively understand this novel process and its contribution(s) to cell physiology: How are transporters labeled and sorted for degradation? Does it occur during other fusion events? Can the ILF pathway degrade surface polytopic proteins? Does it contribute to longevity? Is this pathway conserved in metazoans? Primarily using S. cerevisiae and its vacuolar lysosome as models, I will complete five objectives to answer these questions and achieve my goal of understanding the molecular underpinnings of the ILF pathway, its physiology and how it may promote longevity in eukaryotic cells. This ambitious series of studies will be completed within 5 years by a motivated team of 1 postdoctoral fellow, 3 graduate students and an undergraduate student who will master cutting-edge methods in genetics, microscopy, biochemistry and cell biology - desirable skills needed to pursue careers in academia and industry. We anticipate that the ILF pathway will be equally critical to lysosomes as TOR- and TFEB-signaling, whereby it remodels membranes to accommodate changes in cell metabolism and other biology, akin to the importance of plasma membrane remodeling by endocytosis that underlies diverse physiology. Anticipated results will also help reveal the secret of nature's holy grail, and future work will translate this state-of-the-art knowledge into applications to prolong longevity, supporting development of intellectual property and related biotechnologies in Canada.

尽管他们可能没有意识到，但每个人都回收利用来维持地球上的生命，至少从细胞生物学家的角度来看是这样。这是因为所有真核细胞，包括构成你我的细胞，都依赖于被称为溶酶体的细胞器来回收生物材料。溶酶体回收不需要的或受损的细胞成分，并通过将其转化为重要的营养来源来清除细胞外碎片或病原体。因此，当细胞饥饿时，需要溶酶体活动来维持新陈代谢，并在细胞老化时清除积累在细胞中的有毒生物材料。为了发挥作用，这些动态细胞器依靠营养转运蛋白将分解代谢的产物(氨基酸、脂类、核酸)返回细胞进行重复使用。但人们对这些转运蛋白知之甚少，包括它们是如何被调控或降解的。直到最近，当我们在模式生物酿酒酵母中发现了一种新的过程，称为光内片段(ILF)途径，当受到损伤时，它选择性地降解溶酶体转运蛋白，以响应底物水平，或通过TOR信号传递细胞衰老的重要中介。这个过程选择性地将转运蛋白分选到膜的一个区域，该区域在同型溶酶体膜融合时被管腔水解酶内化和降解。但要全面理解这一新的过程及其对细胞生理学的贡献(S)，必须回答许多悬而未决的问题：转运蛋白是如何标记和分类的？它是否发生在其他核聚变事件期间？ILF途径能降解表面多聚体蛋白吗？它有助于延年益寿吗？这种途径在后生动物中是保守的吗？主要以酿酒酵母及其空泡溶酶体为模型，我将完成五个目标来回答这些问题，并实现我的目标，了解ILF途径的分子基础，它的生理作用，以及它如何促进真核细胞的寿命。这一雄心勃勃的系列研究将在5年内由一个由1名博士后、3名研究生和1名本科生组成的充满动力的团队完成，他们将掌握遗传学、显微镜、生物化学和细胞生物学的尖端方法--这些技能是在学术界和工业界追求职业生涯所必需的。我们预计ILF途径对溶酶体的作用与TOR-和TFEB-信号一样重要，通过它重塑细胞膜以适应细胞代谢和其他生物学的变化，类似于通过内吞作用进行质膜重塑的重要性，内吞作用是不同生理基础的基础。预期的结果还将有助于揭示大自然圣杯的秘密，未来的工作将把这一最先进的知识转化为延长寿命的应用，支持加拿大知识产权和相关生物技术的发展。