Regulation of TRAF2 Activity in Normal and Tumor Cells

正常细胞和肿瘤细胞中 TRAF2 活性的调节

• 批准号: 7339874
• 负责人: HASEM HABELHAH
• 金额: $ 20.34万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-17 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7339874
• 关键词: Abbreviations; Adaptor Signaling Protein; Antibodies; Apoptosis; Appendix; Binding; C-terminal; Cell Death; Cells; Condition; Doctor of Philosophy; Exhibits; Fingers; Foundations; Human; Hydrogen Peroxide; Ink; Light; MAPK14 gene; MAPK8 gene; Maps; Mediating; Melanoma Cell; Membrane; Molecular; N-terminal; NF-kappa B; Nature; Pathway interactions; Phosphorylation; Phosphorylation Site; Physiological; RNA Interference; Regulation; Resistance; Role; Serine Phosphorylation Site; Signal Pathway; Signal Transduction; Site; Stress; TNF receptor-associated factor 2; TRAF Domain; TRAF2 gene; Technology; Transcription Factor AP-1; Tumor Necrosis Factor Receptor; Ubiquitination; Work; cancer cell; cytokine; in vivo; neoplastic cell; response; tumor; ubiquitin-protein ligase

TRAF2 is a key adaptor protein that regulates the IKK, JNK and p38 signaling pathways in response to cytokines and stress, leading to activation of the critical transcription factors AP-1 and NF-kB. Human tumors often exhibit either elevated expression or altered localization of TRAF2, resulting in constitutive IKK activation and increased resistance to stress-induced apoptosis. The mechanism that brings about such deregulation of TRAF2 stability and activity in cancer cells is still elusive. In earlier studies we demonstrated the role of Siah2 in regulating TRAF2 stability in resonse to stress stimulation. We also demonstratedthat TRAF2's own RING-dependent ubiquitination induces its translocation to membrane rafts and concomitant activation of JNK, but not of IKK. However, the molecular mechanism underlying the regulation of TRAF2 activity is far from being understood. We mapped TNFa-induced and Akt/PKC-mediated TRAF2 phosphorylation sites. Importantly, TRAF2 phosphorylation within the RING finger domain is required for TRAF2-mediated activation of IKK, whereas phosphorylation within the TRAF domain was found important for limiting TNFa-induced IKK activation. These findings provide the foundation to our hypothesis that TRAF2-mediated signaling is tightly regulated by a post-translational phosphorylation. In this second revision, we will focus on Akt/PKC-mediated TRAF2 phosphorylation and elucidate its physiological and pathophysiological significance in TRAF2-mediated activation of diverse signaling pathways, with which we propose to carry out the following specific aims: 1. Characterize the mechanism by which newly identified TRAF2 phosphorylation regulates TNFa-induced and TRAF2-mediated activation of the JNK and NF-kB pathways. 2. Assess the role of Akt and PKC in the phosphorylation of TRAF2 and TRAF2-mediated activation of the JNK and NF-kB pathways. 3. Define the relationship between Akt- and PKC-mediated TRAF2 phosphorylation and stress-induced cell death. Aim-4. Assess the pathophysiological relevance of TRAF2 phosphorylation in melanoma cell resistance to stress-induced cell death. Our work will shed new light on the regulation of TRAF2 phosphorylation by PKC and Akt and their role in the regulation of tumor cell resistance to stress-induced cell death.

TRAF2 是一种关键的接头蛋白，可调节 IKK、JNK 和 p38 信号通路以响应 细胞因子和应激，导致关键转录因子 AP-1 和 NF-kB 的激活。人类肿瘤 通常表现出 TRAF2 表达升高或定位改变，导致组成型 IKK 激活并增加对应激诱导的细胞凋亡的抵抗力。产生这种现象的机制 癌细胞中 TRAF2 稳定性和活性的失调仍然难以捉摸。在早期的研究中我们证明了 Siah2 在调节 TRAF2 稳定性以响应应激刺激中的作用。我们还证明了 TRAF2 自身的 RING 依赖性泛素化诱导其易位至膜筏并伴随 激活 JNK，但不激活 IKK。然而，TRAF2 调控的分子机制 活动远未被理解。我们绘制了 TNFa 诱导和 Akt/PKC 介导的 TRAF2 磷酸化位点。重要的是，RING指结构域内的 TRAF2 磷酸化是 TRAF2 介导的 IKK 激活，而 TRAF 结构域内的磷酸化被发现很重要 用于限制 TNFa 诱导的 IKK 激活。这些发现为我们的假设提供了基础 TRAF2 介导的信号传导受到翻译后磷酸化的严格调节。在这一秒 修订后，我们将重点关注 Akt/PKC 介导的 TRAF2 磷酸化并阐明其生理和功能 TRAF2 介导的多种信号通路激活的病理生理学意义，我们利用它 建议实现以下具体目标： 1. 描述新确定的机制 TRAF2 磷酸化调节 TNFa 诱导和 TRAF2 介导的 JNK 和 NF-kB 激活 途径。 2. 评估 Akt 和 PKC 在 TRAF2 磷酸化和 TRAF2 介导的磷酸化中的作用 JNK 和 NF-kB 通路的激活。 3. 定义 Akt 和 PKC 介导之间的关系 TRAF2 磷酸化和应激诱导的细胞死亡。目标4。评估病理生理学相关性 TRAF2 磷酸化在黑色素瘤细胞抵抗应激诱导的细胞死亡中的作用。我们的工作将焕发出新的光彩 阐明PKC和Akt对TRAF2磷酸化的调控及其在肿瘤细胞调控中的作用 抵抗压力诱导的细胞死亡。