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: 10610818
• 负责人: PETER S BRZOVIC
• 金额: $ 52.72万
• 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/10610818
• 关键词: Ablation; 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.

项目概要 BARD1（BRCA1 相关 RING 结构域蛋白-1）是乳房的重要伙伴， 卵巢癌肿瘤抑制蛋白 BRCA1，包含在一组用于 评估疑似遗传性癌症倾向的患者，尤其是乳腺癌和卵巢癌 癌症。尽管如此，人们对 BARD1 的细胞作用知之甚少。该项目旨在 通过在分子水平上定义 BARD1 如何发挥作用来解决这一严重的知识差距 DNA 损伤修复和转录抑制。最终目标是使 关于患者中发现的突变的潜在功能丧失表型的预测。 BRCA1 及其专性伙伴 BARD1 形成异二聚体复合物，该复合物涉及 许多细胞过程，最值得注意的是，转录调控和 DNA 修复 同源重组。唯一与酶活性直接相关的酶活性 BRCA1/BARD1 复合物是一种 E3 泛素连接酶。 BRCA1 的 RING 结构域和 BARD1 特异性且独特地靶向核小体组蛋白 H2A 尾部的位置。这 BRCA1/BARD1 放置这些 Ub 标记的能力对其转录至关重要 同源基因对某些基因的抑制及其在 DNA 损伤修复中的功能 重组。虽然 BRCA1 的 RING 是所有连接酶活性所必需的，但乳腺癌患者 BARD1 RING 中的突变显示出 H2A 泛素化特有的功能丧失。一个 新确定的 BRCA1/BARD1 RING 结构域的冷冻电镜结构 核小体揭示 BARD1 决定 E3 连接酶的方向，因此， 确定 H2A 上的修饰位点。在这个项目中，我们将建立在这个令人兴奋的新 结构洞察力，以解决 BARD1 RING 之外的区域如何为其功能做出贡献 BRCA1 的重要伙伴。