Signal Termination by PHLPP, PH domain Leucine-rich repeat Protein Phosphatase

通过 PHLPP、PH 结构域富含亮氨酸的重复蛋白磷酸酶终止信号

• 批准号: 7892059
• 负责人: ALEXANDRA C. NEWTON
• 金额: $ 27.81万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-10 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7892059
• 关键词: Address; Automobile Driving; Binding; Biochemistry; Breast Cancer Cell; Cell Survival; Cells; Colon Carcinoma; Disease; Disease Progression; Enzymatic Biochemistry; Family member; Funding; Genes; Genetic; Goals; Human; Imaging technology; Isoenzymes; Kinetics; Lead; Life; Location; Malignant Neoplasms; Measures; Mediating; Molecular; Mutation; PH Domain; Phosphoric Monoester Hydrolases; Protein Isoforms; Protein phosphatase; RNA Splicing; Reporting; Research Personnel; Role; Signal Pathway; Signal Transduction; Specificity; Substrate Specificity; Tertiary Protein Structure; Testing; Time; Tumor Suppressor Proteins; cell motility; leucine-rich repeat protein; malignant breast neoplasm; mouse model; novel; programs; protein phosphatase 2C; scaffold; sodium-hydrogen exchanger regulatory factor; tool; tumor

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to understand the molecular and cellular mechanisms of signal termination mediated by the novel phosphatase PHLPP (PH domain Leucine-rich repeat Protein Phosphatase; pronounced 'flip') that we discovered in the preceding funding period. The central hypothesis driving this proposal is that PHLPP terminates signaling pathways that are turned on by PDK- 1, notably Akt signaling pathways, and that specificity in termination is achieved by subcellular location and macromolecular interactions. 1. Molecular Mechanisms of PHLPP: The goal of this section is to understand the enzymology and biochemistry of PHLPP, a new PP2C family member. Specifically, we will examine the kinetics and substrate specificity of the three PHLPP isozymes, the alternatively spliced PHLPP1 (a and () and PHLPP2, and develop tools for cellular studies in Aims 2 and 3. 2. Cellular Mechanisms of PHLPP: The goal of this section is to understand the mechanisms that control the function of PHLPP in cells. We will test the hypothesis that the PDZ binding motifs of the PHLPP isoforms selectively tether them to specific NHERF PDZ domain proteins, forming a scaffolding network that allows effective control of the amplitude and duration of Akt signaling. We will characterize additional PHLPP binding partners in cells and, using novel imaging technologies, we will measure PHLPP activity in real time in live cells. 3. PHLPP in disease: This aim addresses the role of PHLPP in human cancers. The PHLPP1 and PHLPP2 genes are located on the chromosomal loci reported to be the most commonly deleted in colon cancer and breast cancer, respectively. The function of PHLPP isozymes in controlling the amplitude of Akt signaling poises them as prime candidates to be the elusive tumor suppressors harbored on these loci. To test this, we will screen human tumors for mutations in PHLPP, address the role of PHLPP in cell migration in breast cancer cells, and develop a mouse model to address how genetic deletion of PHLPP could lead to abnormalities in cell survival and proliferation.

描述（由申请人提供）：本提案的长期目标是了解我们发现的新型磷酸酶 PHLPP（PH 结构域富含亮氨酸重复蛋白磷酸酶；发音为“flip”）介导的信号终止的分子和细胞机制在之前的资助期内。推动这一提议的中心假设是 PHLPP 终止由 PDK-1 打开的信号传导途径，特别是 Akt 信号传导途径，并且终止的特异性是通过亚细胞定位和大分子相互作用实现的。 1. PHLPP 的分子机制：本节的目标是了解 PP2C 家族新成员 PHLPP 的酶学和生物化学。具体来说，我们将检查三种 PHLPP 同工酶（选择性剪接的 PHLPP1 (a 和 () 和 PHLPP2) 的动力学和底物特异性，并开发目标 2 和 3 中的细胞研究工具。 2. PHLPP 的细胞机制：目标本节旨在了解控制细胞中 PHLPP 功能的机制，我们将检验 PHLPP 亚型的 PDZ 结合基序的假设。选择性地将它们与特定的 NHERF PDZ 结构域蛋白连接，形成一个支架网络，可以有效控制 Akt 信号传导的幅度和持续时间。我们将表征细胞中其他 PHLPP 结合伙伴，并使用新型成像技术，实时测量 PHLPP 活性。 3. PHLPP 在疾病中的作用：该目标解决了 PHLPP 在人类癌症中的作用。据报道，PHLPP1 和 PHLPP2 基因位于最常见的染色体位点上。分别在结肠癌和乳腺癌中缺失的 PHLPP 同工酶在控制 Akt 信号幅度方面的功能使它们成为这些位点上难以捉摸的肿瘤抑制因子的主要候选者。为了测试这一点，我们将筛查人类肿瘤中 PHLPP 的突变，研究 PHLPP 在乳腺癌细胞迁移中的作用，并开发一种小鼠模型来研究 PHLPP 的基因删除如何导致细胞存活和增殖异常。