Signaling via proteolysis of the interferon receptor

通过干扰素受体的蛋白水解传递信号

• 批准号: 7252514
• 负责人: John J. Krolewski
• 金额: $ 25.83万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-04-10 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7252514
• 关键词: Address; Alzheimer' s Disease; Apoptotic; Binding; Biochemistry; Biological Assay; Cell Line; Cell Nucleus; Cell Proliferation; Cells; Characteristics; Cleaved cell; Complex; DNA Binding; Data; Development; Disease; Endopeptidases; Extracellular Domain; Family; Gene Expression Regulation; Generations; Genes; Genetic Transcription; Goals; Grant; Growth; Human; ISGF3G protein; Immune response; Interferon Receptor; Interferon Type I; Interferons; Investigation; Knock-out; Malignant Neoplasms; Mediating; Metalloproteases; Modality; Modeling; Mutation; Nuclear; Nuclear Translocation; Pathway interactions; Peptide Hydrolases; Phosphorylation; Physiological; Physiology; Process; Production; Protein Precursors; Protein Tyrosine Kinase; Proteins; Proteolysis; Research Design; Resistance; Response Elements; Signal Pathway; Signal Transduction; Site; Stimulus; Testing; Tetradecanoylphorbol Acetate; Therapeutic; Transmembrane Domain; Viral; Virus Diseases; cancer therapy; cytokine; design; mutant; notch protein; presenilin; prevent; promoter; receptor; research study; response; size

DESCRIPTION (provided by applicant): The type I interferons (IFNs) regulate the innate immune response to viral infection and have anti-proliferative and pro-apoptotic action which has been exploited in the treatment of cancer. Furthermore, type I IFN signaling is a model for the large family of helical cytokines, which regulate many aspects of proliferation, differentiation and the immune response. Thus, studying type I IFN signaling is expected to impact our understanding of cancer and other diseases and facilitate the development of therapeutic modalities. Type I IFNs can signal through the JAK-STAT pathway. In brief, receptors (IFNaRI and IFNaR2) rely on JAK tyrosine kinases (Tyk2 and Jak1) to initiate signaling. IFN binding triggers JAK activation and phosphorylation of two STATs (Statl and Stat2). The STATs then heterodimerize, complex with the interferon regulatory factor 9 (Irf9), translocate to the nucleus and bind a response element upstream of IFN-regulated genes. Previously, this grant has supported our investigation of multiple aspects of this canonical signaling cascade. Recently, in the course of investigating the interaction between Stat2 and IFNaR2, we found that type I IFNs induce a two-step proteolysis of the IFNaR2 subunit in a manner that resembles the mechanism employed by Notch and the Alzheimer's precursor protein. Cleavage also occurs spontaneously and in response to various stimuli that induce PKC activation. An initial cleavage, mediated by the metalloprotease TACE, releases most of the ectodomain and a second cleavage by the intramembrane presenilin proteases releases the intracellular domain (ICD) of IFNaR2. Preliminary data indicates the ICD is capable of nuclear translocation and that this fragment of IFNaR2 can modulate gene transcription and inhibit cell proliferation, suggesting that type I IFNs might signal via a regulated intramembranous proteolysis (RIP) mechanism. Thus, the overall goal of this renewal application is to determine if type I IFNs can signal, in a physiologically relevant context, via RIP. Moreover, does RIP act in lieu of, or in addition to, the canonical JAK-STAT signaling pathway? Four specific aims are proposed to test this hypothesis. Aim 1 determines if type I IFNs induce cleavage and nuclear translocation of the endogenous IFNaR2 ICD and characterizes the mechanisms(s) initiating production of the ICD. Next, the key experiments in this proposal will test the hypothesis that cleavage is required for physiological effects of IFN by identifying the protease cleavage sites on IFNaR2 (aim 2) and determining if mutations which prevent cleavage perturb the physiological effects of the type I IFNs (aim 3). Finally, aim 4 addresses the mechanism of ICD mediated gene regulation by testing the hypothesis that the ICD functions in a complex with Stat2 and Irf9 to regulate gene transcription.

描述(申请人提供)：I型干扰素(IFN)调节对病毒感染的先天免疫反应，并具有抗增殖和促凋亡作用，已被用于癌症治疗。此外，I型干扰素信号是螺旋细胞因子大家族的模型，它调节着增殖、分化和免疫反应的许多方面。因此，研究I型干扰素信号有望影响我们对癌症和其他疾病的理解，并促进治疗方式的发展。I型IFN可以通过JAK-STAT通路发出信号。简而言之，受体(IFNaRI和IFNaR2)依赖JAK酪氨酸激酶(TYK2和JAK1)来启动信号传递。干扰素结合触发JAK激活和两个STAT1和STAT2的磷酸化。然后，STATS与干扰素调节因子9(Irf9)形成复合体，异源二聚体，转位到细胞核，并结合干扰素调节基因上游的反应元件。此前，这笔拨款支持了我们对这一规范信号级联的多个方面的研究。最近，在研究Stat2和IFNaR2之间的相互作用过程中，我们发现I型IFN诱导IFNaR2亚基的两步蛋白分解，其方式类似于Notch和阿尔茨海默病前体蛋白所采用的机制。裂解也是自发发生的，并对诱导PKC激活的各种刺激做出反应。金属蛋白酶TACE介导的第一次切割释放了大部分胞外结构域，膜内早老素蛋白水解酶第二次切割释放了IFNaR2的胞内区(ICD)。初步数据表明，ICD具有核转位的能力，并且IFNaR2的这一片段能够调节基因转录和抑制细胞增殖，提示I型IFN可能通过调节膜内蛋白分解(RIP)机制来传递信号。因此，该更新应用的总体目标是确定I型IFN是否可以在生理相关的上下文中通过RIP发送信号。此外，RIP是否替代或补充了规范的JAK-STAT信号通路？为了检验这一假说，本文提出了四个具体目标。目的1确定I型IFN是否诱导内源性IFNaR2ICD的卵裂和核转位，并研究其启动ICD产生的机制(S)。接下来，这项建议中的关键实验将通过鉴定IFNaR2上的蛋白酶裂解位点(目标2)并确定阻止切割的突变是否扰乱I型IFN的生理效应(目标3)，来检验干扰素的生理效应需要切割这一假说。最后，目标4通过验证ICD在与Stat2和Irf9的复合体中的功能来调节基因转录的假设，阐述了ICD介导的基因调控的机制。