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.

可逆蛋白磷酸化，即蛋白质磷酸化和去磷酸化，是一种基本 生物学各个方面的调节机制。蛋白质磷酸酶2a（PP2A）是主要的Ser/Thr 哺乳动物细胞中的蛋白质磷酸酶和对致癌的主要肿瘤抑制蛋白 转型。 PP2A的核心成分由脚手架亚基（亚基）和催化 ubunit（c亚基）。由PP2A甲基转移酶（PMT）控制的C亚基的甲基化和 PP2A甲基酯酶（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）至少通过与B亚基结合至少部分地拮抗PP2A的功能 PP2A A-C异二聚体。 DLPHA4蛋白通过形成A拮抗PP2A的正常功能 与pp2a的c亚基复合物。尽管进行了严格的研究，但PP2A的结构和机制 在很大程度上未知。 PP2A核心的系统X射线晶体学和生化分析 已启动成分，调节蛋白及其修饰酶。取得了重大进展 已实现；这里提出的工作将以以下特定目的为基础： （1）确定PME，PMT及其同源复合物与 底物/抑制剂。 （2）确定pp2a的核心成分A-C异二聚体的结构。 （3） 涉及A-C异二聚体和B亚基的PP2A全酶的结构的测定。 （4） 与小肿瘤抗原（ST）结合的PP2A A-C异二聚体的结构的测定。 （5） 单独的DLPHA4结构和与PP2A的C亚基的结构确定。提议 该赠款应用中的具体目的代表了揭开结构的重要而系统的努力 PP2A调节的机制。蛋白质及其同源的一般溶液特性通常 复合物使这项事业可行。