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（由申请人提供）：可逆蛋白质磷酸化，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。蛋白质磷酸酶2a（PP2A）是哺乳动物细胞中的主要SER/THR蛋白磷酸酶，而主要的肿瘤抑制蛋白抗致癌。 PP2A的核心成分由脚手架亚基（一个亚基）和催化Ubunit（C亚基）组成。由PP2A甲基转移酶（PMT）和PP2A甲基酯酶（PME）控制的C亚基的甲基化对于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）至少通过与B亚基与PP2A A-C异二聚体结合至少部分地拮抗PP2A的功能。 DLPHA4蛋白通过与PP2A的C亚基形成复合物，拮抗PP2A的正常功能。尽管进行了激烈的研究，但PP2A的结构和机制基本上仍然未知。已经开始启动系统的X射线晶体学和生化分析PP2A核心成分，其调节蛋白及其修饰酶。已经取得了重大进展；这里提出的工作将基于初步结果，其特定目的是：（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）确定pp2a的核心成分A-C异二聚体的结构。 （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）单独测定DLPHA4的结构，并与PP2A的C亚基进行复杂。该赠款申请中提出的具体目的代表了揭示PP2A调节的结构机制的重要而系统的努力。蛋白质及其同源复合物的一般溶液特性通常使这项工作可行。