IDENTIFICATION OF SUBSTRATES FOR UBIQUITIN-PROTEIN LIGASES IN YEAST

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 泛素是细胞中应用最广泛的蛋白质修饰之一，现在人们普遍认识到泛素化在细胞生理的几乎每一个方面都起着关键的调节作用。蛋白质的泛素化是通过一个酶的级联反应发生的，在这个过程中，泛素从泛素活化酶传递到泛素结合酶，然后通过泛素-蛋白质连接酶的作用与底物中的赖氨酸残基相连。在级联反应中，泛素蛋白连接酶通过直接结合底物或招募结合底物的辅助因子来赋予底物特异性。通过基于同源性的搜索，预测在人类中存在数百种泛素-蛋白质连接酶，这突显了泛素化在细胞调控中的重要性和深度。然而，大多数泛素蛋白连接酶的功能尚未确定，因此我们对任何特定泛素蛋白连接酶的底物群知之甚少。 为了解决这个问题，我们的长期目标是以一种公正的方式阐明任何假定的或已知的泛素蛋白连接酶的靶标范围，特别是那些与疾病有关的泛素蛋白连接酶。我们最初正在开发泛素蛋白质组学技术，使用酵母作为模型系统，因为它易于处理。然而，许多酵母泛素化途径也有人类对应的，因此我们将获得有价值的生物信息，并为开发哺乳动物版本的这项技术提供立足点。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ubiquitin is one of the cell's most broadly utilized protein modifications, and it is now widely appreciated that ubiquitination serves critical regulatory roles in virtually every aspect of cellular physiology. Protein ubiquitination occurs through an enzymatic cascade in which ubiquitin is passed from an ubiquitin activase to an ubiquitin conjugase, and then attached to lysine residue within a substrate through the action of an ubiquitin-protein ligase. In the cascade, the ubiquitin-protein ligase imparts the substrate specificity, either by directly binding the substrate or by recruiting ancillary factors that bind substrates. Through homology-based searches, hundreds of ubiquitin-protein ligases are predicted to exist in humans, underscoring the importance and depth of ubiquitination in cellular regulation. However, the function for most of these has not yet been characterized, and so we know very little about the cohort of substrates for any particular ubiquitin-protein ligase. To address this problem, our long-term goal is to elucidate, in an unbiased way, the scope of targets for any putative or known ubiquitin-protein ligase, especially those implicated in disease. We are initially developing ubiquitin proteomics technologies using yeast as a model system because of its tractability. However, many yeast ubiquitination pathways also have human counterparts, so we will gain valuable biological information as well as providing a foothold in developing a mammalian version of this technology.