Studies on ROC1-dependent E3 Ubiquitin Ligases

描述(申请人提供)：在过去的十年里，我们在揭示干细胞因子E3泛素连接酶在调节细胞生长、信号转导和肿瘤抑制活性中所扮演的重要角色方面取得了令人兴奋的进展。SCF通过将其目标蛋白标记为死亡标签链(称为泛素)，从而导致它们的破坏，从而起到“分子死亡触发器”的作用。干细胞因子途径的调节缺陷在包括癌症在内的人类疾病中都很明显。然而，我们才刚刚开始欣赏其复杂的调控网络，在开发有效的药理药物方面，我们仍处于起步阶段。我们的长期目标是了解SCF的确切功能和相关的“分子死亡触发因素”，并开始努力开发针对人类癌症的治疗策略。我们项目的短期目标是确定SCF如何将泛素死亡标签连接到蛋白质靶标上。具体地说，我们发现SCF需要几个玩家，其中包括一个名为CDc34的工作酶，一个名为NeddS的激活剂，以及一个名为DCN-1的新玩家。SCF作为总计划制定者，协调将泛素死亡标签转移到目标。有趣的是，我们发现，除非与Nedds结合在一起，否则SCF一直处于不活跃状态，这需要DCN-1。此外，SCF还需要与CDC34联系，从而使这匹“工作马”发挥作用。我们的项目是开发分子和细胞工具来探索SCF、NeddS、CDC34和DCN-1的不同部分，并确定这些部分是如何组合在一起发挥作用的。

DESCRIPTION (provided by applicant): In the past decade, we have enjoyed thrilling advancement in revealing the essential roles played by the SCF E3 ubiquitin ligases in regulating cell growth, signal transduction and tumor suppressor activity. SCF functions as a "molecular death trigger" by tagging its target proteins with a chain of death-tag, known as ubiquitin, thereby leading to their destruction. Defective regulation of the SCF pathway is manifest in human diseases including cancers. However, we have only begun to appreciate its complex regulatory networks and we are still in our infancy with respect to developing effective pharmacologic agents. Our long-range goal is to understand the precise functioning of SCF and related "molecular death triggers," and initiate efforts to develop therapeutic strategies against human cancers. The short-term goal of our project is to determine how SCF attaches the ubiquitin death-tag to a protein target. Specifically, we found that SCF requires several players that include a work-horse enzyme named Cdc34, an activator called NeddS, and new player called DCN-1. SCF acts as a master plan-maker that coordinates the transfer of the ubiquitin death-tag to a target. Interestingly, we discovered that SCF is kept in an inactive state unless being held together with NeddS, which requires DCN-1. In addition, SCF is required to contact Cdc34, thus making the "work-horse" work. Our project is to develop molecular and cellular tools to probe for various parts on SCF, NeddS, Cdc34 and DCN-1, and to determine how these parts are put together to function.