regulation of the cullin family E3 ubiquitin ligases

在阐明cullin的关键调控作用方面已经取得了相当大的进展。 基于真核细胞中广泛生物学过程的E3泛素连接酶。然而， 我们还远远不了解它们的错综复杂，我们才刚刚开始欣赏它们 复杂的监管网络。而对依赖于cullin的蛋白水解酶的调节存在缺陷 途径在包括癌症在内的人类疾病中是明显的，我们在这方面还处于初级阶段 由于对药物的机理认识不足，导致开发有效的药理药物 这些过程。因此，如果我们要理解异常增长，我们必须有基本的 了解库林斯如何调节蛋白质分解以及这些过程是如何被调控的。 最近，我们发现了cullin蛋白家族中的一个新成员，称为CUL7， 包含cullin和DOC签名域。值得注意的是，CUL7组装了一个类似SCF的 E3Ub连接酶复合体，由Skp1、CUL7、ROC1和一个以前未鉴定的F-box组成 蛋白质，Fbx29。我们建议阐明基于CUL7/Fbx29的E3-1ike的生物学功能 通过识别Fbx29底物(S)介导蛋白质降解的复合体。 NEDD8是一种特定的cullin修饰物，它上调基于cullin的E3 Ub的活性 连接酶。最近，我们克隆了一种Nedd8途径的潜在调节因子，称为hDEN-1，一个 新的Nedd8异肽酶。我们将研究hDEN-1在Ub依赖中的生物学功能 通过评估hDEN-1在调节Nedd8依赖中的功能来研究蛋白质降解途径 在哺乳动物细胞中的SCF活性，以及通过检测这种新的蛋白酶的生物学作用 使用S.pombe和果蝇模型系统。 PVHL肿瘤抑制因子通过组装含有cullin 2的E3连接酶发挥作用 靶向HIF-10泛素化和降解。最近的研究表明，一种新的邮寄- 翻译修饰，即脯氨酸羟化，在调节pVHL/HIF-1中起着核心作用 路径。PHO1/SM20家族脯氨酸对HIF-10_564位的羟基化作用 羟基酶是其与pVHL相互作用启动泛素化所必需的。最近， 我们已经确定了一种刺激PhD1/SM20 Pro功能的细胞活性 羟基酶。我们建议确定这种新活性的分子同一性，这可能 已被证明是pVHL/HIF-1通路的另一个关键调控因子。

Considerable progress has been made in elucidating the critical regulatory role of cullin- based E3 ubiquitin ligases over a wide array of biological processes in eukaryotic cells. However, we are far from understanding their intricacies and we have only begun to appreciate their complex regulatory networks. While defective regulation of the cullin-dependent proteolysis pathways is manifest in human diseases including cancers, we are still in our infancy with respect to developing effective pharmacologic agents due to insufficient mechanistic understanding of these processes. Thus, if we are to understand aberrant growth, we must have fundamental knowledge of how cullins mediate proteolysis and how these processes are regulated. Recently, we have identified a novel member of the cullin protein family called CUL7, containing both the cullin and DOC signature domains. Remarkably, CUL7 assembles an SCF-like E3 Ub ligase complex composed of Skpl, CUL7, ROC1, and a previously uncharacterized F-box protein, Fbx29. We propose to elucidate the biological function of the CUL7/Fbx29-based E3-1ike complex in mediating protein degradation by identifying substrate(s) of Fbx29. Nedd8 is a specific cullin modifier that up-regulates the activity of cullin-based E3 Ub ligases. Recently, we have cloned a potential regulator of the Nedd8 pathway called hDEN-1, a novel Nedd8 isopeptidase. We will investigate the biological function of hDEN-1 in Ub-dependent protein degradation pathways by assessing the function of hDEN-1 in regulating Nedd8-dependent SCF activities in mammalian cells, as well as by examining the biological role of this novel protease using S. pombe and Drosophila model systems. The pVHL tumor suppressor functions by assembling a cullin 2-containing E3 ligase that targets HIF-10_ for ubiquitination and degradation. Recent studies have revealed that a novel post- translational modification, prolyl hydroxylation, plays a central role in regulating the pVHL/HIF-1 pathway. Hydroxylation of HIF-10_ at proline residue 564, by the PHO1/SM20 family prolyl hydroxylase, is required for its interaction with pVHL to initiate the ubiquitination. More recently, we have identified a cellular activity that stimulates the function of the PHD1/SM20 prolyl hydroxylase. We propose to determine the molecular identity of this novel activity, which may prove to be yet another critical regulator of the pVHL/HIF-1 pathway.