Structure and function of CSL, the transcriptional regulator in the Notch pathway

Notch 通路转录调节因子 CSL 的结构和功能

• 批准号: 7196762
• 负责人: Rhett Kovall
• 金额: $ 24.48万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-30 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7196762
• 关键词: DNA; X ray; library; mutant; neoplasm /cancer; proteins

DESCRIPTION (provided by applicant): Aberrant activation from the Notch pathway is a causative factor in the leukemogenesis of T-cell acute lymphoblastic leukemia (T-ALL), the most common leukemia found in children. Oncogenic Notch signaling is also observed in other blood-borne cancers, solid tumor malignancies, and virally induced tumors. The considerable extent to which aberrant Notch signaling is associated with human neoplasias emphasizes the need for developing novel therapeutics that pharmacologically manipulate the pathway. Our long-term goal is to gain a molecular understanding of how transcriptional regulation is achieved in the Notch pathway. The conserved transcription factor CSL is the primary regulator of transcription in the Notch pathway, and its centrality makes it an attractive target for therapeutic intervention. While progress has been made in identifying binding partners of CSL, the structural details as to how these complexes regulate transcription are poorly understood. The objective of this proposal focuses on characterizing CSL-mediated transcription complexes with corepressors and viral proteins. We hypothesize that allosteric changes in CSL and/or overlapping coregulator binding sites on CSL underlie the conversion of CSL from a repressor to an activator of transcription. To test our hypothesis and accomplish our objective the following three aims will be pursued. (1) We will analyze the CSL binding surfaces utilized by transcriptional coregulators by creating a library of CSL interfacial mutants based on the CSL-Notch-Mastermind active transcription complex. (2) We will determine the minimal domains necessary for the corepressors CIR, SMRT, and SHARP to interact with CSL and pursue X-ray structures for these complexes. (3) We will delineate the domains of the herpesvirus proteins EBNA2, RTA, and LANA necessary for binding CSL and determine X-ray structures for these complexes. Completion of this proposal will illuminate the molecular details that comprise CSL transcription complexes with corepressors and herpesvirus proteins, thereby fundamentally advancing the field, and provide a structural basis for rationally developing drugs that target CSL-mediated transcription complexes. "Lay language" - The abnormal action of the cellular Notch pathway results in human cancers. We are determining structural models for Notch pathway components in order to better understand pathway function, biology and tumorigenesis, which will have an impact on disease diagnosis, prevention, and treatment.

描述（由申请人提供）：Notch 通路的异常激活是 T 细胞急性淋巴细胞白血病 (T-ALL) 白血病发生的致病因素，T-ALL 是儿童中最常见的白血病。致癌Notch信号传导也在其他血源性癌症、实体瘤恶性肿瘤和病毒诱导的肿瘤中观察到。异常的Notch信号传导在很大程度上与人类肿瘤相关，这强调了开发从药理学上操纵该通路的新疗法的必要性。我们的长期目标是获得对 Notch 通路中转录调控如何实现的分子理解。保守的转录因子 CSL 是 Notch 通路中转录的主要调节因子，其中心地位使其成为治疗干预的有吸引力的目标。虽然在识别 CSL 结合伴侣方面取得了进展，但人们对这些复合物如何调节转录的结构细节知之甚少。该提案的目标侧重于表征 CSL 介导的转录复合物与辅阻遏物和病毒蛋白的关系。我们假设 CSL 的变构变化和/或 CSL 上重叠的辅助调节子结合位点是 CSL 从转录抑制子转变为转录激活子的基础。为了检验我们的假设并实现我们的目标，我们将追求以下三个目标。 (1) 我们将通过创建基于 CSL-Notch-Mastermind 活性转录复合物的 CSL 界面突变体库来分析转录共调节器利用的 CSL 结合表面。 (2) 我们将确定辅阻遏物 CIR、SMRT 和 SHARP 与 CSL 相互作用所需的最小结构域，并寻找这些复合物的 X 射线结构。 (3) 我们将描绘结合 CSL 所需的疱疹病毒蛋白 EBNA2、RTA 和 LANA 的结构域，并确定这些复合物的 X 射线结构。该提案的完成将阐明包含 CSL 转录复合物、辅阻遏物和疱疹病毒蛋白的分子细节，从而从根本上推进该领域的发展，并为合理开发针对 CSL 介导的转录复合物的药物提供结构基础。 “外行语言”——细胞Notch通路的异常作用会导致人类癌症。我们正在确定Notch通路成分的结构模型，以便更好地了解通路功能、生物学和肿瘤发生，这将对疾病的诊断、预防和治疗产生影响。