PI 3-Kinase Isoforms and Insulin Action

PI 3-激酶同工型和胰岛素作用

• 批准号: 6894229
• 负责人: C RONALD KAHN
• 金额: $ 40.68万
• 依托单位: JOSLIN DIABETES CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6894229
• 关键词: JUN kinase; biological signal transduction; cell line; disease /disorder model; enzyme activity; enzyme mechanism; enzyme structure; gene targeting; genetically modified animals; hormone regulation /control mechanism; insulin; insulin receptor; insulin sensitivity /resistance; intermolecular interaction; isozymes; laboratory mouse; mitogen activated protein kinase; noninsulin dependent diabetes mellitus; phosphatidylinositol 3 kinase; protein localization; protein structure function; receptor coupling; stoichiometry; yeast two hybrid system

DESCRIPTION (provided by applicant): This is a competitive renewal which has focused on the role of PI 3-kinase in insulin action. Over the past 4 years, we have defined the similarities, differences and complementary roles of various isoforms of PI 3-kinase regulatory subunits in insulin action. This has been accomplished by creation and characterization of mice and cell lines in which specific isoforms of PI 3-kinase have been deleted or overexpressed. This has led to new hypotheses about the important role of stoichiometry between regulatory and catalytic subunits in insulin action, the potential for other signals emanating from the regulatory subunit of PI 3-kinase involved in regulation of PIP3 half-life and the stress kinase pathways, and the role of Akt as a downstream effector of PI 3-kinase. In the next five-year period, we propose to extend our previous observations and focus on these hypotheses in a series of new specific aims: 1. Define the role of the N-terminal domains of p85alpha/beta and the short isoforms p50alpha and p55alpha/AS53 in insulin signaling, including the potential roles of these domains in signaling mediated by the regulatory subunits independent of PI 3-kinase activity, especially the JNK and p38 MAPK pathways, and the link between p85 and lipid phosphatase PTEN, and their differential ability to generate and stabilize PIP3. 2. Define the specific molecules interacting with the N-terminal region of p85, p55 and p50 regulatory subunits through yeast and bacterial two-hybrid screening, determine their role in signaling and subcellular localization of the PI 3-kinase enzyme, and their relationship to signaling through Racl and cdc42. 3. Explore the role of stoichiometry in regulation of in insulin sensitivity by defining the mechanisms regulating expression of various isoforms of regulatory subunit in normal and pathological states and analyzing the promoters of the p85a, p55a and p50a gene in vivo and in vitro. 4. Determine the role of stoichiometry of PI 3-kinase catalytic subunits p110alpha and p110beta (equivalent to age-1 in C. elegans) in insulin signaling, insulin sensitivity and longevity, and define the role of the major downstream effector Aktl in rodents and cell lines by creating and characterizing tissue specific knockout mice alone and in combination with Akt2 knockout.

描述（由申请方提供）：这是一项竞争性更新，重点关注PI 3-激酶在胰岛素作用中的作用。在过去的4年里，我们已经确定了PI 3-激酶调节亚基的各种亚型在胰岛素作用中的相似性，差异性和互补作用。这已经通过创建和表征小鼠和细胞系来实现，其中PI 3-激酶的特定同种型已经缺失或过表达。这导致了新的假说的重要作用之间的化学计量的调节和催化亚基在胰岛素的行动，潜在的其他信号发出的PI 3-激酶的调节亚基参与调节PIP 3的半衰期和应激激酶途径，和Akt作为PI 3-激酶的下游效应的作用。在未来五年内，我们建议扩展我们以前的观察，并在一系列新的具体目标中关注这些假设： 1.定义p85 α/β和短亚型p50 α和p55 α/AS 53的N-末端结构域在胰岛素信号传导中的作用，包括这些结构域在由独立于PI 3-激酶活性的调节亚基介导的信号传导中的潜在作用，特别是JNK和p38 MAPK通路，以及p85和脂质磷酸酶PTEN之间的联系，以及它们产生和稳定PIP 3的不同能力。 2.通过酵母和细菌双杂交筛选，确定与p85、p55和p50调节亚基N端区域相互作用的特异性分子，确定它们在PI 3-激酶信号传导和亚细胞定位中的作用，以及它们与Racl和cdc 42信号传导的关系。 3.通过对正常和病理状态下胰岛素敏感性调节亚基不同亚型的表达调控机制的研究，以及对p85 a、p55 a和p50 a基因启动子的体内、外分析，探讨胰岛素敏感性调节中化学计量学的作用。 4.确定PI 3-激酶催化亚基p110 α和p110 β化学计量的作用（相当于C. elegans）在胰岛素信号传导、胰岛素敏感性和寿命中的作用，并通过单独和与Akt 2敲除组合产生和表征组织特异性敲除小鼠来确定主要下游效应子Akt 1在啮齿动物和细胞系中的作用。