A proteomics-based approach for the analysis of sumoylation patterns in normal and apoptotic human cells

Sumoylation是一种蛋白质修饰，是由SUMO蛋白与目标蛋白的共价和可逆附着所定义的。这一途径是哺乳动物细胞存活所必需的，这证明了它的关键作用。在自然条件下，只有少量的巯基化蛋白被发现被修饰，这使得它们的鉴定变得困难。尽管如此，已经有几十种细胞和病毒蛋白被SUMO修饰，而且很可能还有更多的蛋白有待鉴定。虽然summoylation的结果已经被很好地描述为单个蛋白质，但summoylation（作为一种途径）在特定细胞功能中的重要性却知之甚少。拟议的研究计划将使用蛋白质组学工具来纯化涉及特定途径的人类巯基化蛋白。SUMO靶点将被确定，然后我们将使用遗传工具来研究SUMO化对这些单个蛋白质的影响。这种蛋白质组学/功能双重方法将首先应用于研究sumoylation与细胞凋亡（程序性细胞死亡）以及细胞周期进展之间的关系。具体来说，我们将确定在不同细胞周期阶段和凋亡诱导后被聚合或去聚合的蛋白质。然后我们将详细分析summoylation对这些蛋白质的作用。我们期望本项目能够发现SUMO的新蛋白靶点，并显示该修饰在正常细胞和凋亡细胞中的作用。这项工作还可能确定旨在调节细胞周期的癌症治疗的新靶点。从长远来看，我们将应用这种方法来研究sumo化在其他情况下（如病毒感染）的重要性。

Sumoylation, a protein modification, is defined by the covalent and reversible attachment of the protein SUMO to the target protein. This pathway is required for mammalian cell survival, arguing for its critical role.  Only small amounts of sumoylated proteins are found modified in natural conditions, making their identification difficult. Nonetheless, dozens of cellular and viral proteins haven been shown to be modified by SUMO, and it is likely that many more remain to be identified. Although the outcome of sumoylation has been well characterized for individual proteins, the importance of sumoylation (as a pathway) in specific cellular functions is poorly understood. The proposed research program will use proteomic tools for the purification of human sumoylated proteins involved in specific pathways. SUMO targets will be identified, then we will use genetic tools to investigate the impact of sumoylation for these individual proteins. This proteomics/functional dual approach will be first applied to investigate the relationships between sumoylation and apoptosis (programmed cell death) as well as cell cycle progression. Specifically, we will identify proteins that are either sumoylated or desumoylated at various cell cycle stages and following apoptosis induction. Then we will analyze in details the role of sumoylation for these proteins. We expect that this project will identify new protein targets of SUMO and show the role of this modification in the normal and apoptotic cell. This work might also identify new targets for cancer therapies aimed at regulating the cell cycle. On the long term, we will apply this approach to investigate the importance of sumoylation in other contexts such as viral infections.