Viral oncoproteins: Revealing novel structural motifs to target tumor suppressors

病毒癌蛋白：揭示靶向肿瘤抑制因子的新结构基序

基本信息

批准号：
8696462
负责人：
Clodagh O'Shea
金额：
$ 40.26万
依托单位：
SALK INSTITUTE FOR BIOLOGICAL STUDIES
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-06-01 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8696462
关键词：
Address Adenoviruses Affinity Avidity Binding Binding Sites Biological Assay Biology C-terminal Cell Nucleus Cleaved cell Complex DNA Tumor Viruses Development Dimerization Dominant-Negative Mutation Engineering Epigenetic Process Evolution Gene Targeting Genes Genome Genomics Goals Heterochromatin Higher Order Chromatin Structure Homologous Gene Infection Knowledge Malignant Neoplasms Modeling Molecular Mutagenesis Mutate Mutation NBS1 gene Nuclear Oncogene Proteins Oncogenes Oncolytic Pathway interactions Peptides Polymers Proteins Research Role Site Structure Subgroup Tail Testing Therapeutic Agents Tumor Suppressor Proteins Viral Viral Cancer Viral Genes Viral Proteins Virus Virus Diseases base cancer therapy cell growth cellular targeting comparative genomics dimer insight lytic replication mutant neoplastic cell next generation novel novel therapeutics protein protein interaction public health relevance structural biology therapeutic target tumor

项目摘要

DESCRIPTION (provided by applicant): This proposal will reveal the structural mechanisms and motifs that enable a tiny viral oncoprotein to target and disrupt multiple critical tumor suppressor pathways. The ultimate goal is to exploit this knowledge to develop novel viral therapies against intractable tumor targets. The evolution of minimal DNA tumor virus' genomes has selected for small viral oncoproteins that hijack critical cellular protein interaction network that are also targeted by mutations in cancer. However, the structural basis for the dominant interactions of small adenovirus oncoproteins has remained elusive, as none of their complete structures have been solved. This represents a fundamental gap in the understanding of Adenovirus biology and the structural principles that enable small viral proteins to 'win'. To address this the structure of an E4-ORF3 dimer at 2.1¿ was solved. E4-ORF3 is a 13kDa protein that assembles a nuclear polymer network that binds and disrupts the PML, TRIM24, and MRE11/RAD50/NBS1 (MRN) tumor suppressor complexes. In addition, E4-ORF3 induces heterochromatin silencing at p53 target genes and anti-viral genes through an unknown mechanism. In contrast to the archetypal Adenovirus oncoprotein, E1A, E4-ORF3 has a discrete ordered structure and is not a structural homologue of any known cellular polymers or oncogenes. E4-ORF3 forms dimer subunits with a central beta-core that further co-assemble through reciprocal and non-reciprocal exchanges of their C-terminal tails. The higher order assembly of E4-ORF3 is required for creating avidity-driven interactions with PML and an emergent MRN binding interface. This proposed research builds on these studies. Aim 1 will reveal the structure and higher order oligomeric interactions that drive the assembly of wild type E4-ORF3 and are required for its functions in disrupting multiple tumor suppressors to facilitate viral replication. Aim 2 will use the structure of E4-ORF3 as a rational basis to identify new structural motifs that target the PML, MRN and TRIM24 tumor suppressor complexes, which are important therapeutic targets. Discrete E4-ORF3 mutations will be engineered that selectively uncouple its interactions with different tumor suppressor complexes to reveal their respective contributions in viral infection. This will provide a rational basis for the development of novel vral cancer therapies that selectively replicate in tumor cells with particular tumor suppressor pathway mutations. E4-ORF3 dimerization creates a novel binding-cleft that determines the sites of its assembly in the nucleus and is required for silencing p53 target genes. Aim 3 will use a combination of viral engineering and integrative comparative genomics approaches to determine if residues within the cleft target the E4-ORF3 assembly to specific genomic loci where it binds to a motif in H10 and to induce repressive heterochromatin silencing of p53 and anti-viral genes. This will reveal new targets and mechanisms that silence p53 in infection and that could also be disrupted by mutations in cancer.

描述（由申请人提供）：该提案将揭示使微小病毒癌蛋白能够靶向并破坏多种关键肿瘤抑制途径的结构机制和基序，最终目标是利用这些知识来开发针对难治性肿瘤靶点的新型病毒疗法。最小DNA肿瘤病毒基因组的进化选择了小病毒癌蛋白，这些蛋白劫持了关键的细胞蛋白相互作用网络，这些网络也是癌症突变的目标。然而，小腺病毒癌蛋白的主要相互作用的结构基础已经改变。仍然难以捉摸，因为它们的完整结构尚未得到解决，这代表了对腺病毒生物学和使小病毒蛋白能够“获胜”的结构原理的理解存在根本差距。 2.1?? E4-ORF3 是一种 13kDa 蛋白，可组装核聚合物网络，结合并破坏 PML、TRIM24 和 MRE11/RAD50/NBS1 (MRN) 肿瘤抑制复合物。此外，E4-ORF3 还可诱导 p53 靶点的异染色质沉默。基因和抗病毒基因通过未知的机制与原型腺病毒癌蛋白相反， E1A、E4-ORF3 具有离散的有序结构，并且不是任何已知细胞聚合物或癌基因的结构同源物。E4-ORF3 形成具有中心 β 核心的二聚体亚基，该二聚体亚基通过其相互和非相互交换进一步共组装。 E4-ORF3 的 C 末端尾部是与 PML 和新兴 MRN 结合界面创建亲合力驱动的相互作用所必需的。目标 1 将揭示驱动野生型 E4-ORF3 组装的结构和高阶寡聚相互作用，并且是其破坏多种肿瘤抑制因子以促进病毒复制的功能所必需的。 -ORF3作为识别靶向PML、MRN和TRIM24肿瘤抑制复合物的新结构基序的合理基础，这些是重要的治疗靶点，将被选择性地设计为离散的E4-ORF3突变。解开其与不同肿瘤抑制复合物的相互作用，揭示它们各自在病毒感染中的作用，这将为开发新型病毒癌症疗法提供合理的基础，该疗法可在具有特定肿瘤抑制途径突变的肿瘤细胞中选择性复制，从而产生一种新的病毒癌症疗法。 Aim 3 将使用新的结合裂缝，它决定了其在细胞核中的组装位点，并且是沉默 p53 靶基因所必需的。结合病毒工程和综合比较基因组学方法，确定裂口内的残基是否将 E4-ORF3 组装靶向特定基因组位点，在该基因座上它与 H10 中的基序结合，并诱导 p53 和抗病毒基因的抑制性异染色质沉默。揭示了在感染中沉默p53并且也可能被癌症突变破坏的新靶点和机制。