Defining the programmed proteome rejuvenation underlying gametogenesis

摘要 电池的完整性取决于其组件的质量。这些成分包括蛋白质，这些蛋白质是 负责执行大多数细胞功能，许多是通过组织成稳定的复合体来实现的。一个标志性的 衰老的细胞是蛋白质完整性的破坏，或蛋白质的稳定，这是由关键蛋白质的损伤引起的 随着时间的推移，会导致更多的累积损伤，最终导致细胞功能障碍。具体的 最容易受到损伤并推动其积累的蛋白质组成分尚不清楚，但 后代的生存依赖于一种细胞类型--配子--的保护，使其免受遗传损伤 从它们的前体细胞中分离出来的成分。在简单发芽酵母的配子发生过程中，作为前体细胞是 分化为配子后，我们观察到许多细胞结构和蛋白质的降解，随后 它们的重新合成和重组。这种细胞重组与积极的年轻化计划有关。 这使得年轻的配子同样可以从年老的或年轻的前体细胞中产生。这些机制可以 对这一自然复兴计划的贡献尚不清楚，但它可以通过外源 一个减数分裂转录因子在衰老的有丝分裂细胞中的表达，表明它是可移植的。 因此，酵母中的配子发生为我们提供了观察细胞向我们展示什么蛋白质和 它需要重置和重组以确保细胞年轻的复合体，以及它实现这一目标所使用的机制。 特别令人感兴趣的是具有基础或“看家”功能的蛋白质，包括核糖体，它们是长的- 生活在有丝分裂细胞中，但在配子发生过程中降解并以巨大的能量成本替换。我们还观察到 在配子发生期间，丰富的管家复合体，包括蛋白酶体的重组，以及 一些蛋白质，包括超氧化物歧化酶1(SOD1)，在其降解时聚集。 总之，这些观察表明，酵母细胞在配子发生过程中重塑蛋白质组是一种品质。 控制措施。在这里，我们建议确定关键的蜂窝组件集，重点是“内务” 蛋白质，当配子从前体细胞产生时被重置。我们使用蛋白质组学方法在全球范围内 确定配子构建过程中蛋白质复合体的变化，并具体确定蛋白酶体 随着时间的推移重塑和活动。我们研究了蛋白质聚集之间的联系，包括SOD1，和 蛋白质的氧化和降解。最后，我们确定了驱动密钥的具体退化机制 蛋白质组重塑的各个方面，并测试它们对配子恢复活力和延长寿命的必要性 外源激活时的扩展。该项目将建立一个图谱，以揭示蛋白质和复合体 对于年轻的细胞身份来说足够重要，足以证明在配子期间重新设置它们的能量成本是合理的 以及那些毒性可能足以保证它们被有效清除的物质。通过识别和 操纵配子使用的特定途径来选择性地重塑他们的蛋白质组，我们将找到策略 这可以被用来对抗和防止与年龄相关的细胞损伤。

ABSTRACT The integrity of a cell depends on the quality of its components. These components include proteins, which are responsible for executing most cellular functions, many through organization into stable complexes. A hallmark of aged cells is the breakdown of protein integrity, or proteostasis, which results from the damage to key proteins and complexes over time, leading to more accumulated damage, and ultimately cell dysfunction. The specific proteome components that are most susceptible to damage and that drive its accumulation remain unclear, but the survival of future generations depends on protection of one cell type—gametes—from inheriting damaged components from their precursor cell. During gametogenesis in the simple budding yeast, as a precursor cell is differentiated into gametes, we observe the degradation of many cellular structures and proteins, followed by their resynthesis and reorganization. This cellular restructuring is associated with an active rejuvenation program that allows equivalently young gametes to be produced from old or young precursor cells. The mechanisms that contribute to this natural rejuvenation program are not known, but it can be recapitulated by exogenous expression of a meiotic transcription factor in aged mitotic cells, suggesting that it is portable. Gametogenesis in yeast thus offers the opportunity to watch as the cell shows us what proteins and complexes it needs to reset and reorganize to ensure cellular youth, and the mechanisms it uses to achieve this. Of particular interest are proteins of basal or “housekeeping” function, including the ribosome, which are long- lived in mitotic cells, but degraded and replaced at great energetic cost during gametogenesis. We also observe reorganization of abundant housekeeping complexes, including the proteasome, during gametogenesis, and aggregation of some proteins, including superoxide dismutase 1 (Sod1), at the time of their degradation. Together, these observations suggest that yeast cells remodel their proteome during gametogenesis as a quality control measure. Here, we propose to identify the key set of cellular components, with a focus on “housekeeping” proteins, that are reset as gametes are created from precursor cells. We use a proteomic approach to globally define changes to protein complexes during gamete construction, and specifically determine proteasome remodeling and activity over time. We investigate the links between aggregation of proteins, including Sod1, and protein oxidation and degradation. Finally, we identify the specific degradation mechanisms that drive key aspects of proteome remodeling and test their necessity for gamete rejuvenation and ability to drive lifespan extension when exogenously activated. This project will build an atlas to reveal the proteins and complexes that are important enough for young cell identity to warrant the energetic cost of resetting them during gamete formation, as well as those that may be toxic enough to warrant their active removal. By identifying and manipulating the specific pathways used by gametes to selectively remodel their proteome, we will find strategies that can be co-opted to combat and prevent age-associated cellular damage.