Defining the role of BARD1 in nucleosomal ubiquitylation

定义 BARD1 在核小体泛素化中的作用

• 批准号: 10231875
• 负责人: PETER S BRZOVIC
• 金额: $ 61.91万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10231875
• 关键词: Address; Ankyrin Repeat; Architecture; BARD1 gene; BRCA1 Protein; BRCA1 gene; BRCT Domain; Behavior; Binding; Biochemical; Biological; Biophysics; Breast Cancer Patient; Cell physiology; Cells; Chemicals; Clinical; Complex; Cryoelectron Microscopy; DNA; DNA Repair; Detection; Deuterium; Disease; EMSA; Genes; Goals; Hereditary Malignant Neoplasm; Histone H2A; Histones; Hydrogen; Knowledge; Learning; Length; Ligase; Malignant neoplasm of ovary; Modification; Molecular; Molecular Conformation; Mutation; Nucleosomes; Patients; Phenotype; Poly Adenosine Diphosphate Ribose; Positioning Attribute; Predisposition; Proteins; Reporting; Resected; Resolution; Role; Site; Structure; Tail; Testing; Transcriptional Regulation; Tumor Suppressor Proteins; Ubiquitin; Work; biophysical techniques; cancer predisposition; crosslink; design; gene repression; homologous recombination; insight; loss of function; malignant breast neoplasm; mutant; recruit; shared attention; ubiquitin-protein ligase

PROJECT SUMMARY BARD1 (BRCA1-Associated RING Domain protein-1) is an essential partner of the breast and ovarian cancer tumor-suppressor protein, BRCA1, and is included in a panel of genes used to evaluate patients with suspected hereditary cancer predisposition, especially breast and ovarian cancers. Despite this, little is known about the cellular role of BARD1. This project aims to address this serious gap in knowledge by defining at a molecular level how BARD1 contributes to DNA damage repair and to transcriptional repression. An ultimate goal is to enable predictions regarding potential loss-of-function phenotypes for mutations identified in patients. BRCA1 and its obligate partner BARD1 form a heterodimeric complex that is implicated in numerous cellular processes, most notably, transcriptional regulation and DNA repair via homologous recombination. The sole enzymatic activity directly associated with the BRCA1/BARD1 complex is as an E3 Ubiquitin ligase. The RING domains of BRCA1 and BARD1 specifically and uniquely target positions on the tail of nucleosomal histone H2A. The ability of BRCA1/BARD1 to place these Ub marks is essential to both its transcriptional repression of certain genes and its function in DNA damage repair by homologous recombination. While the RING of BRCA1 is required for all ligase activity, breast cancer patient mutations in the RING of BARD1 display loss-of-function specifically for ubiquitylation of H2A. A newly determined cryo-EM structure of the BRCA1/BARD1 RING domains sitting atop a nucleosome reveals that BARD1 dictates the orientation of the E3 ligase and, therefore, determines the site(s) of modification on H2A. In this project, we will build on this exciting new structural insight to address how regions outside BARD1’s RING contribute to its function as an essential partner of BRCA1.

项目摘要 Bard1（BRCA1相关环域蛋白1）是乳房的重要伴侣， 卵巢癌肿瘤 - 抑制蛋白BRCA1，并包括在用于 评估怀疑的雌性癌症患者，尤其是乳房和卵巢 癌症。尽管如此，对Bard1的细胞作用知之甚少。这个项目旨在 通过在分子级定义Bard1如何贡献的分子级来解决这一严重的差距 进行DNA损伤修复和转录表达。最终目标是启用 关于患者发现突变的潜在功能丧失表型的预测。 BRCA1及其专性合作伙伴Bard1构成了一个异二聚体复合体 许多细胞过程，最著名的是转录调控和DNA修复 同源重组。唯一与 BRCA1/BARD1复合物是E3泛素连接酶。 BRCA1和 Bard1在核小体组蛋白H2A的尾部具体而独特的靶位置。这 BRCA1/BARD1放置这些Ub标记的能力对于既至关重要 抑制某些基因及其在DNA损伤修复中的功能 重组。虽然所有连接酶活性都需要BRCA1环，而乳腺癌患者则需要 BARD1环中的突变表现出针对H2a泛素化的功能丧失。一个 BRCA1/BARD1环域的新确定的冷冻EM结构位于A 核小体揭示了Bard1决定E3连接酶的方向，因此， 确定H2A修改的位点。在这个项目中，我们将基于这个令人兴奋的新 结构性见解，以解决Bard1戒指之外的地区如何促进其作为一个功能 BRCA1的重要合作伙伴。