Pharmacological Study of G-proteins in Gene Regulation

G蛋白基因调控的药理学研究

• 批准号: 6874915
• 负责人: RICHARD D YE
• 金额: $ 26.04万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6874915
• 关键词: G protein; Kaposi' s sarcoma; arrestins; cell surface receptors; enzyme activity; gene induction /repression; genetically modified animals; laboratory mouse; nuclear factor kappa beta; phosphatidylinositol 3 kinase; phosphorylation; posttranslational modifications; protein protein interaction; protein tyrosine kinase; receptor coupling

DESCRIPTION (provided by applicant): Activation of numerous G-protein-coupled receptors (GPCRs) results in cell proliferation that contributes to the progression of diseases such as Kaposi's sarcoma. We have recently reported that GPCRs activate nuclear factor kappa B (NF-kappaB), which induces the expression of a large number of genes responsible for cell growth and survival. The NF-KappaB activation mechanims have been extensively characterized using model cytokines such as TNFalpha, but little is known about the G-protein pathways that activate this important transcription factor. Using pharmacological inhibitors and dominant negative DNA constructs that disrupt G-protein signaling, we have found that G-proteins vary in their ability to activate NF-KappaB. While many Galpha and Gbetagamma subunits mediate NF-KappaB activation, certain Galpha subunits can also inhibit NF-KappaB. Experiments are proposed in 3 specific aims to determine the mechanisms by which G-proteins regulate NFKappaB activation. In Aim 1, we will investigate the signaling pathways utilized by G13 for NF-KappaB activation. We hypothesize that signaling effectors downstream of the G13-p115RhoGEF-RhoA pathway play a critical role in NF-KappaB activation through p65 transactivation. Aim 2 is focused on Gbetagamma dimers in the differential activation of PI-3 kinases and Src protein tyrosine kinases, both leading to NF-KappaB activation but with different 1kappabetaalpha kinetics. We propose to identify the factors that determine the activation of these effectors of Gbetaalpha. The role of beta-arrestins in Gbetagamma-mediated NF-KappaB activation will also be examined. In Aim 3, we will determine how NF-KappaB activation is negatively regulated by G-proteins. A working hypothesis is that Galphai proteins have the opposite function of Gbetagamma in that they mediate inhibition of NF-KappaB activation in cells stimulated with proinflammatory agents. We will investigate a possible role of Galphai2 in suppression of NF-KappaB. A potential link to Galkphai-mediated inhibition of Raf-1 pathway will be examined. Collectively, these studies are expected to reveal how G-protein mediated proximal signaling events lead to different cytoplasmic and nuclear signaling and transcriptional regulation, and to identify potential sites for therapeutic intervention.

描述（由申请人提供）：许多G蛋白偶联受体（GPCR）的激活导致细胞增殖，这有助于诸如Kaposi的肉瘤等疾病的发展。我们最近报告说，GPCR激活了核因子Kappa B（NF-KAPPAB），该因子诱导了大量负责细胞生长和存活的基因的表达。 NF-kappab激活机制已使​​用模型细胞因子（例如TNFALPHA）进行了广泛的表征，但对激活该重要转录因子的G蛋白途径知之甚少。使用破坏G蛋白信号传导的药理抑制剂和显性负DNA构建体，我们发现G蛋白激活NF-kappab的能力有所不同。尽管许多Galpha和Gbetagamma亚基都介导NF-kappab激活，但某些Galpha亚基也可以抑制NF-kappab。在3个特定目的中提出了实验，以确定G蛋白调节NFKAPPAB激活的机制。在AIM 1中，我们将研究G13用于NF-kappab激活的信号传导途径。我们假设G13-P115RHOGEF-RHOA途径下游的信号传导效应子通过p65反式激活在NF-kappab激活中起关键作用。 AIM 2集中在PI-3激酶和SRC蛋白酪氨酸激酶的差异激活中的Gbetagamma二聚体上，均导致NF-kappab激活，但具有不同的1Kappababetaalpha动力学。我们建议确定确定gbetaalpha效应子激活的因素。还将检查β-arrestin在Gbetagamma介导的NF-kappab激活中的作用。在AIM 3中，我们将确定NF-kappab激活如何受G蛋白负责。一个可行的假设是，加尔法蛋白具有Gbetagamma的相反功能，因为它们介导了促炎剂刺激的细胞中NF-kappab激活的抑制作用。我们将研究Galphai2在抑制NF-kappab中的可能作用。将检查与Galkphai介导的RAF-1途径抑制的潜在联系。总的来说，这些研究有望揭示G蛋白介导的近端信号传导事件如何导致不同的细胞质和核信号传导以及转录调控，并确定治疗干预的潜在部位。