Structural biololgy of tumor suppressor PP2A and its regulatory proteins

肿瘤抑制因子PP2A及其调节蛋白的结构生物学

• 批准号: 7262759
• 负责人: YIGONG SHI
• 金额: $ 22.12万
• 依托单位: PRINCETON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7262759
• 关键词: Active Sites; Applications Grants; Baculoviruses; Binding; Biochemical; Biology; Bos taurus; Brain; Catalytic Domain; Cattle; Cells; Classification; Complex; DNA Viruses; Enzymes; Foundations; Holoenzymes; Human; In Vitro; Insecta; Investigation; Mammalian Cell; Methylation; Molecular; Molecular Conformation; Molecular Structure; Oncogenic; Phosphoric Monoester Hydrolases; Phosphorylation; Play; Principal Investigator; Property; Protein Dephosphorylation; Protein Phosphatase 2A Regulatory Subunit PR53; Protein phosphatase; Proteins; Recombinants; Regulation; Resolution; Roentgen Rays; Role; Simian virus 40; Solutions; Structure; Structure-Activity Relationship; Substrate Specificity; System; Transferase; Tumor Antigens; Tumor Suppressor Proteins; Viral Proteins; Work; design; dimer; enzyme mechanism; esterase; genetic regulatory protein; inhibitor/antagonist; insight; reconstitution; scaffold

DESCRIPTION (provided by applicant): Reversible protein phosphorylation, namely protein phosphorylation and dephosphorylation, is a fundamental regulatory mechanism in all aspects of biology. Protein phosphatase 2A (PP2A) is a dominant Ser/Thr protein phosphatase in mammalian cells and a principal tumor suppressor protein against oncogenic transformation. The core component of PP2A consists of the scaffolding subunit (A subunit) and the catalytic ubunit (C subunit). The methylation of the C subunit, controlled by the PP2A methyl transferase (PMT) and the PP2A methyl esterase (PME), is essential to the function of PP2A. The PP2A A-C hetero-dimer and the regulatory subunit (B subunit) assemble into a functional holoenzyme. The DMA virus SV40 Small Tumor Antigen (ST) antagonizes the function of PP2A at least in part by competing with the B subunit for binding to the PP2A A-C hetero-dimer. The Dlpha4 protein antagonizes the normal function of PP2A by forming a complex with the C subunit of PP2A. Despite intense investigation, the structure and mechanisms of PP2A remain largely unknown. Systematic X-ray crystallographic and biochemical analyses of the PP2A core component, its regulatory proteins, and its modifying enzymes have been initiated. Significant progress has been achieved; the work proposed here will build on the preliminary results with the following specific aims: (1) Determination of the crystal structures of PME, PMT, and their cognate complexes with substrate/inhibitor. (2) Determination of the structure of the core component A-C hetero-dimer of PP2A. (3) Determination of the structure of a PP2A holoenzyme involving A-C hetero-dimer and a B subunit. (4) Determination of the structure of a PP2A A-C hetero-dimer bound to Small Tumor Antigen (ST). (5) Determination of the structure of Dlpha4 alone and in complex with the C subunit of PP2A. The proposed specific aims in this grant application represent an important and systematic effort to unravel the structural mechanisms of PP2A regulation. The generally excellent solution properties of the proteins and their cognate complexes make this undertaking feasible.

描述（申请人提供）：可逆的蛋白质磷酸化，即蛋白质磷酸化和去磷酸化，是生物学各个方面的基本调节机制。蛋白磷酸酶 2A (PP2A) 是哺乳动物细胞中的主要 Ser/Thr 蛋白磷酸酶，也是对抗致癌转化的主要肿瘤抑制蛋白。 PP2A的核心成分由支架亚基（A亚基）和催化亚基（C亚基）组成。 C 亚基的甲基化由 PP2A 甲基转移酶 (PMT) 和 PP2A 甲酯酶 (PME) 控制，对于 PP2A 的功能至关重要。 PP2A A-C 异二聚体和调节亚基（B 亚基）组装成功能性全酶。 DMA 病毒 SV40 小肿瘤抗原 (ST) 至少部分通过与 B 亚基竞争与 PP2A A-C 异二聚体的结合来拮抗 PP2A 的功能。 Dlpha4蛋白通过与PP2A的C亚基形成复合物来拮抗PP2A的正常功能。尽管进行了大量研究，PP2A 的结构和机制仍然很大程度上未知。对 PP2A 核心成分、其调节蛋白及其修饰酶的系统 X 射线晶体学和生化分析已经启动。已取得重大进展；这里提出的工作将建立在初步结果的基础上，具有以下具体目标：（1）确定PME、PMT及其与底物/抑制剂的同源复合物的晶体结构。 (2)PP2A核心成分A-C异二聚体的结构测定。 (3)确定涉及A-C异二聚体和B亚基的PP2A全酶的结构。 (4)确定与小肿瘤抗原(ST)结合的PP2A A-C异二聚体的结构。 (5)确定Dlpha4单独和与PP2A的C亚基复合的结构。本次拨款申请中提出的具体目标代表了为阐明 PP2A 监管结构机制所做的重要而系统的努力。蛋白质及其同源复合物通常具有优异的溶液特性，使这项工作成为可能。