Studies on ROC1-dependent E3 Ubiquitin Ligases

描述（由申请人提供）：在过去的十年中，我们在揭示SCF E3泛素连接酶在调节细胞生长，信号转导和肿瘤抑制活性方面发挥的重要作用方面取得了令人兴奋的进展。SCF作为一种“分子死亡触发器”，通过用死亡标签链（即泛素）标记其靶蛋白，从而导致它们被破坏。SCF通路的缺陷调控在包括癌症在内的人类疾病中是明显的。然而，我们才刚刚开始认识到其复杂的调控网络，在开发有效的药理学制剂方面，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“分子死亡触发器”，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附着在蛋白质目标上。具体来说，我们发现SCF需要几个参与者，包括一种名为Cdc34的工作马酶，一种名为NeddS的激活剂和一种名为DCN-1的新参与者。SCF作为一个总体计划制定者，协调泛素死亡标签向目标的转移。有趣的是，我们发现SCF保持在非活性状态，除非与NeddS结合在一起，这需要DCN-1。此外，SCF需要与Cdc34接触，从而使“主力”工作。我们的项目是开发分子和细胞工具来探测SCF， NeddS， Cdc34和DCN-1的各个部分，并确定这些部分如何组合在一起发挥作用。

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.