FUNCTIONAL CHARACTERIZATION OF ARF REGULATORY FACTORS

ARF 调节因子的功能特征

• 批准号: 3752425
• 负责人: R A KAHN
• 金额: --
• 依托单位: DIVISION OF CANCER TREATMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3752425
• 关键词: ADP ribosylation; antibiotics; enzyme activity; eukaryote; exocytosis; fatty acylation; gene expression; guanine nucleotide binding protein; guanosinetriphosphatases; human tissue; intracellular membranes; intracellular transport; membrane lipids; myristates; phosphatidylinositols; phospholipids; posttranslational modifications; protein kinase A; protein purification; protein structure function; transcription factor

The main objectives of this project are the elucidation of the cellular functions of the family of ADP-ribosylation factors (ARFs) and the mechanism of their regulation. Increasing evidence has accumulated in the past year that supports our hypothesis that membrane phospholipids play a critical and dynamic role in the actions of ARF proteins. As Brefeldin A (BFA) has recently been shown to affect ARF functions and cellular distribution, we have expanded our efforts to include a better understanding of the mechanism of BFA action. ARF proteins are unique among the approximately 100 known GTP binding proteins in having a strict dependence on phospholipids to allow nucleotide exchange. Recent work suggests that in addition to a general lipid dependence there are also distinct effects of specific phospholipids that dramatically effect ARF activities. Specifically, ARF binds PIP2 with high affinity, resulting in a protein with reduced affinity for guanine nucleotides. Thus, we are testing the hypothesis that lipids may be the source of the guanine nucleotide exchange factor, observed for many other GTP binding proteins. The N-myristoylation of ARF proteins is a normal co-translation modification occurring in eukaryotic cells. The role of the myristate moiety is also under investigation and may serve as a model for other regulatory myristoylated proteins; e.g. p60 src, cAMP dependent protein kinase, etc. A protein with the ability to specifically bind ARF and promote the GTPase activity by ARF1 has been identified and partially purified. This ARF-GAP (GTPase activating protein) is under investigation as both potential effector and down-regulator of ARF actions.

该项目的主要目标是阐明细胞 ADP-核糖基化因子 (ARF) 家族的功能和 其调节机制。 越来越多的证据已经积累 去年支持了我们的假设，即膜磷脂发挥着 ARF 蛋白的作用中起着关键和动态的作用。 作为布雷菲德菌素 A (BFA) 最近被证明可以影响 ARF 功能和细胞 分布，我们扩大了努力，以包括更好的 了解 BFA 的作用机制。 ARF蛋白是独特的 在大约 100 种已知的 GTP 结合蛋白中，具有严格的 依赖磷脂来允许核苷酸交换。 最近的工作 表明除了一般的脂质依赖性外，还存在 显着影响 ARF 的特定磷脂的独特作用 活动。 具体来说，ARF 以高亲和力结合 PIP2，从而导致 一种对鸟嘌呤核苷酸亲和力降低的蛋白质。因此，我们是 检验脂质可能是鸟嘌呤来源的假设 核苷酸交换因子，在许多其他 GTP 结合蛋白中观察到。 ARF 蛋白的 N-肉豆蔻酰化是正常的共翻译 真核细胞中发生的修饰。 肉豆蔻酸酯的作用 部分也正在研究中，可以作为其他模型 调节性肉豆蔻酰化蛋白；例如p60 src，cAMP 依赖性蛋白 激酶等具有特异性结合ARF和能力的蛋白质 ARF1 促进 GTP 酶活性的作用已被鉴定并部分 纯化的。 该 ARF-GAP（GTP 酶激活蛋白）正在研究中 作为 ARF 作用的潜在效应器和下调器。