Notch Signaling in Cancer

项目摘要 我的研究项目的动机是了解致癌信号如何促进人类 癌症。我们工作的一个重要方面，使我们的贡献有别于其他人的贡献，就是我们 都集中在关于正常和异常信号分子机制的基本问题上， 强调结构、生化、分子和基于细胞的方法。我的首要研究目标是 获奖期建立在我们在Notch领域近20年的持续贡献基础上，并将 强调回答以下关键问题： I)ADAM家族蛋白水解酶激活正常和致病Notch的分子机制是什么？ 配体通常通过使Notch受体变得敏感，将其从休眠状态转换为信号激活状态 到ADAM家族金属蛋白水解酶在细胞膜外的位置进行蛋白分解，但我们的 对ADAM介导的Notch受体蛋白分解的了解仍然非常不成熟。我们会 阐明完整的ADAM10和ADAM17胞外区的结构，并确定它们之间的相互作用 ADAMS的调节域和催化域在正常和致癌过程中执行Notch蛋白分解 发信号。区分ADAM10活性部位和ADAM17活性部位的结构特征可用于 指导高选择性ADAM10或ADAM17抑制剂的开发。 Ii)Notch核参与转录机制的分子机制是什么 情结？细胞内Notch(ICN)与核内RBPJ转录因子结合导致MAML 招募，但MAML如何与Notch-RBPJ复合体合作诱导 转录仍然是该领域一个基本的悬而未决的问题。通过定义事件的顺序 将Notch1信号和MAML1招募与基因表达变化联系起来，我们将阐明Notch1信号和MAML1招募在基因表达变化中的作用 MAML在癌细胞对Notch激活的反应中的作用 Iii)Notch转录靶标反馈调控的分子机制是什么？作为核心 在不同的细胞类型中，NRARP是Notch信号的组成部分 转导电路，通过与核心Notch结合，充当信号的负反馈调节器 转录复合体。我们的目标将是阐明NRARP招募到Notch的结构基础 转录复合体，揭示组装NRARP抑制复合体的分子机制， 并阐明了抑制NRARP的分子机制。总之，这些研究将揭示出一种 Notch信号调制的核心机制，为新型调节器的开发创造了机会 凹槽信号。

Project Summary The motivation for my research program has been to understand how oncogenic signaling promotes human cancer. An important facet of our work, which distinguishes our contributions from those of others, is that we have focused on fundamental questions about molecular mechanisms of both normal and aberrant signaling, emphasizing structural, biochemical, molecular, and cell-based approaches. My overarching research goals over the award period build from our sustained contributions over almost two decades in the Notch field, and will emphasize answering the following key questions: i) What is the molecular mechanism of normal and pathogenic Notch activation by ADAM-family proteases? Ligands normally convert Notch receptors from a dormant to signaling-active state by rendering them susceptible to proteolysis by ADAM-family metalloproteases at a site immediately external to the cell membrane, yet our understanding of ADAM-mediated proteolysis of Notch receptors remains remarkably rudimentary. We will elucidate the structures of the full ADAM10 and ADAM17 ectodomains, and determine how interplay between the regulatory and catalytic domains of the ADAMs executes Notch proteolysis in normal and oncogenic signaling. Structural features that distinguish the ADAM10 active site from that of ADAM17 can then be used to guide development of highly selective ADAM10 or ADAM17 inhibitors. ii) What is the molecular mechanism of engagement of the transcriptional machinery by Notch nuclear complexes? Binding of intracellular Notch (ICN) to the RBPJ transcription factor in the nucleus leads to MAML recruitment, but how Mastermind-like proteins (MAMLs) cooperate with Notch-RBPJ complexes to induce transcription remains a fundamental unresolved question in the field. By defining the sequence of events connecting Notch1 signaling and MAML1 recruitment to gene expression changes, we will illuminate the role of MAML in the response of cancer cells to Notch activation. iii) What is the molecular mechanism of feedback regulation by Notch transcriptional targets? As a core transcriptional target regulated by Notch in diverse cell types, NRARP is an integral part of the Notch signal transduction circuitry, acting as a negative feedback regulator of signaling by binding to the core Notch transcription complex. Our goals will be to elucidate the structural basis for NRARP recruitment to the Notch transcription complex, uncover the molecular mechanism underlying assembly of NRARP inhibitory complexes, and elucidate the molecular mechanism underlying NRARP inhibition. Together, these studies will uncover a central mechanism of Notch signal modulation, and create opportunities for development of novel regulators of Notch signaling.