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: 7388987
• 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/7388987
• 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

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 DMAvirus 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.

可逆的蛋白质磷酸化，即蛋白质磷酸化和去磷酸化，是蛋白质的基本磷酸化。 生物学各方面的调节机制。蛋白磷酸酶 2A (PP2A) 是主要的 Ser/Thr 哺乳动物细胞中的蛋白磷酸酶和抗癌的主要肿瘤抑制蛋白 转变。 PP2A的核心成分由支架亚基（A亚基）和催化亚基组成 亚基（C 亚基）。 C 亚基的甲基化，由 PP2A 甲基转移酶 (PMT) 控制 PP2A 甲酯酶 (PME) 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。 DMAvirus SV40 小肿瘤 抗原 (ST) 至少部分通过与 B 亚基竞争结合来拮抗 PP2A 的功能 PP2A A-C 异二聚体。 Dlpha4 蛋白通过形成 PP2A 来拮抗 PP2A 的正常功能。 与 PP2A 的 C 亚基形成复合物。尽管进行了大量研究，但 PP2A 的结构和机制 仍然很大程度上不为人所知。 PP2A 核心的系统 X 射线晶体学和生化分析 成分、其调节蛋白及其修饰酶已经启动。取得了重大进展 已实现；这里提议的工作将以初步结果为基础，并实现以下具体目标： (1) PME、PMT及其同源配合物晶体结构的测定 底物/抑制剂。 (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 C 亚基复合的结构。拟议的 本次赠款申请中的具体目标代表了为解决结构性问题而做出的重要而系统的努力 PP2A 调节机制。蛋白质及其同源物通常具有优异的溶液特性 综合体使这项事业变得可行。