Ras, Cycling and Inhibition.

Ras，循环和抑制。

• 批准号: 7775011
• 负责人: Nicolas Nassar
• 金额: $ 7.19万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-04 至 2010-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7775011
• 关键词: Adopted; Affinity; Area; Biochemical; Biological Models; Biology; Bladder; Cancer Model; Cell physiology; Colon; Computer Simulation; Databases; Differentiation and Growth; Disease; Enzymes; Family member; GTP Binding; GTP-Binding Proteins; Goals; Guanine Nucleotides; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Hydrolysis; In Vitro; Knowledge; Lung; Malignant Neoplasms; Malignant neoplasm of pancreas; Molecular; Molecular Conformation; Normal Cell; Nucleotides; Oncogenic; Outcome; Pancreas; Pharmaceutical Preparations; Physiological; Preclinical Drug Evaluation; Protein Conformation; Proteins; Reaction; Regulation; Research; Research Project Grants; Research Proposals; Screening procedure; Sequence Homology; Signal Pathway; Signal Transduction; Signaling Protein; Site-Directed Mutagenesis; Specificity; Structure; Techniques; Testing; base; cell growth; design; fight against; flexibility; human disease; improved; in vivo; inhibitor/antagonist; metaplastic cell transformation; molecular dynamics; mutant; prototype; rho; small molecule

DESCRIPTION (provided by applicant): GTP-binding proteins are key switches in signaling pathways that regulate critical cellular functions such as growth and differentiation. Ras, which serves as a prototype for GTP-binding is constitutively activated in a large number of cancers including those of the pancreas, bladder, colon, and lung. The long-term goal of this research is to interfere with the oncogenic forms of Ras in human disease by understanding its cycling. Because oncogenic Ras relies on its intrinsic ability to hydrolyze and exchange GTP, the primary goal of this research proposal is to better our understanding of Ras cycling between the active and inactive states by revealing structures of intermediates of the reactions of GTP hydrolysis and guanine nucleotide exchange. Screening of drugs that will stabilize a non-signaling conformation of oncogenic Ras will be also performed. This proposal is based on findings that altering the flexibility of a hinge region stabilizes structures of Ras that are normally transient. Using this approach, two structures of intermediates along the path for GTP hydrolysis were stabilized as well as an open non-signaling conformation, which is also adopted by the native protein. The first aim of this proposal tests the hypothesis that the open conformation of Ras mimics the structure of an intermediate for nucleotide exchange and the structu-e of an unappreciated native conformation. Additional structures of intermediates for Ras cycling will be generated by altering the flexibility of another hinge region. The generated mutants will be studied using a combination of structural, molecular dynamics, biochemical, and in vivo techniques. The second aim tests the hypothesis that Rho- family members and trimeric G-proteins do not follow the Ras path of GTP hydrolysis and nucleotide exchange despite strong sequence homology. The third aim uses biophysical, structural, and cellular approaches to study how small molecules identified by screening the NCI database interact with the open non-signaling conformation and inhibit oncogenic Ras in a pancreatic cancer model system. The outcome of the proposed research should improve our understanding of the regulation of key signaling proteins and our ability to interfere with their action in human diseases.

描述(申请人提供)：GTP结合蛋白是信号通路中的关键开关，调节关键的细胞功能，如生长和分化。RAS作为GTP结合的原型，在包括胰腺癌、膀胱癌、结肠癌和肺癌在内的大量癌症中被结构性激活。这项研究的长期目标是通过了解RAS的循环来干预人类疾病中RAS的致癌形式。由于致癌RAS依赖于其降解和交换GTP的内在能力，因此本研究计划的主要目的是通过揭示GTP水解和鸟核苷酸交换反应的中间产物的结构，更好地理解RAS在活性和非活性状态之间的循环。还将进行药物筛选，以稳定致癌RAS的非信号构象。这一建议是基于这样的发现：改变铰链区域的灵活性可以稳定通常是瞬时的RAS结构。利用这种方法，GTP水解途径上的两个中间体结构以及一个开放的非信号构象得到了稳定，这一构象也被天然蛋白质采用。这一建议的第一个目的是检验这样的假设，即RAS的开放构象模仿核苷酸交换中间体的结构和未被评价的天然构象的结构。RAS循环中间体的额外结构将通过改变另一个铰链区域的灵活性来产生。产生的突变体将使用结构、分子动力学、生化和体内技术相结合的方法进行研究。第二个目的是检验假设，即Rho家族成员和三聚体G蛋白不遵循Ras的GTP水解和核苷酸交换的路径，尽管序列具有很强的同源性。第三个目标使用生物物理、结构和细胞方法来研究通过筛选NCI数据库确定的小分子如何与胰腺癌模型系统中开放的非信号构象相互作用并抑制致癌RAS。这项拟议的研究结果应该会提高我们对关键信号蛋白调控的理解，以及我们干扰它们在人类疾病中作用的能力。