Regulated Intramembrane Proteolysis of CREB3L1 in Innate Antiviral Response

先天抗病毒反应中 CREB3L1 的调节膜内蛋白水解

• 批准号: 8284448
• 负责人: JIN YE
• 金额: $ 39.34万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-06 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8284448
• 关键词: Accounting; Antiviral Agents; Antiviral Response; Appearance; Binding; Cell Nucleus; Cells; Chronic; Cleaved cell; Cyclic AMP-Responsive DNA-Binding Protein; Drug Delivery Systems; Endoplasmic Reticulum; Family; Gene Targeting; Golgi Apparatus; Hepatitis C; Hepatitis C virus; Human; Immune response; Infection; Interferons; Knowledge; Liver Failure; Mediating; Membrane; Membrane Proteins; Microarray Analysis; Mutation; N-terminal; Names; Pathway interactions; Peptide Hydrolases; Play; Population; Process; Proteins; Proteolysis; RNA Virus Infections; Regulation; Role; Site; Testing; Travel; United States; Viral Proteins; Virus; Virus Diseases; Virus Replication; base; chronic liver disease; drug resistant virus; endoplasmic reticulum stress; hepatoma cell; mutant; novel; public health relevance; site-1 protease; transcription factor

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) infects 3% of the world population and accounts for most cases of chronic liver disease. In the United States, HCV infection is the leading cause of liver failure. Drugs targeting HCV proteins are difficult to be developed owing to the high rate of mutation during HCV replication that allows quick appearance of the drug-resistant viral strains. The current treatment for HCV infection is based on interferon, which mediates an innate immune response against infection of RNA virus. However, this treatment is only partially effective. Thus, understanding other innate antiviral responses may reveal much needed new strategies to treat HCV infection. We have recently identified a novel innate antiviral response that plays an important role in limiting HCV infection in a line of human hepatoma cells. This pathway is mediated by cAMP response element binding protein 3-like 1 (CREB3L1), the function of which was previously unknown. CREB3L1 belongs to a family of transcription factors that are synthesized as membrane-bound precursors inserted in the endoplasmic reticulum (ER), and activated by a process termed regulated intramembrane proteolysis (RIP). Based on our current understanding of RIP, we propose that replication of HCV in the ER results in cleavage of CREB3L1 by Site-1 protease (S1P) and Site-2 protease (S2P). The proteolytic cleavage allows the NH2-terminal fragment of CREB3L1 to be released from the membrane and travel to the nucleus to activate its target genes involved in antiviral responses. These hypotheses will be tested by three specific aims raised in the proposal. Specific Aim 1 will determine the mechanism by which HCV replication stimulates the cleavage of CREB3L1. We will examine whether ER stress induced by expression of HCV- encoded membrane proteins triggers the cleavage of CREB3L1. Specific Aim 2 will determine whether S1P and S2P-catalyzed cleavages of CREB3L1 is required for its antiviral function. The primary approach is to make CREB3L1 mutants that cannot be cleaved by these proteases and examine the effect of the mutations on its antiviral function. Specific Aim 3 will identify the CREB3L1 target genes that inhibit HCV replication by microarray analysis. If these specific aims are achieved, we will have contributed novel information that will significantly enhance our understanding of the innate immune response. This new knowledge may reveal novel drug targets to treat HCV infection. PUBLIC HEALTH RELEVANCE: This project is aimed to study a novel antiviral response mediated by a cellular protein named CREB3L1 that potently inhibits hepatitis C virus (HCV) replication. HCV infects 170 million people worldwide, and the viral infection is the leading cause of liver failure in the United States. The current interferon-based treatment for HCV infection is only partially infective. Thus, understanding the CREB3L1-mediated antiviral pathway, which apparently is interferon-independent, may reveal much needed new strategies to treat HCV infection.

描述（由申请人提供）：丙型肝炎病毒（HCV）感染世界人口的3%，占慢性肝病的大多数病例。在美国，HCV感染是肝衰竭的主要原因。由于HCV复制过程中的高突变率使得耐药病毒株快速出现，因此很难开发针对HCV蛋白的药物。目前对HCV感染的治疗是基于干扰素，其介导针对RNA病毒感染的先天免疫应答。然而，这种治疗方法只是部分有效。因此，了解其他先天性抗病毒反应可能会揭示急需的新策略来治疗HCV感染。 我们最近发现了一种新的先天性抗病毒反应，在限制HCV感染的人肝癌细胞系中起着重要作用。该途径由cAMP反应元件结合蛋白3样1（CREB3L1）介导，其功能以前未知。CREB3L1属于转录因子家族，其作为插入内质网（ER）中的膜结合前体合成，并通过称为调节性膜内蛋白水解（RIP）的过程激活。基于我们目前对RIP的理解，我们提出HCV在ER中的复制导致CREB3L1被位点1蛋白酶（S1P）和位点2蛋白酶（S2P）切割。蛋白水解切割允许CREB3L1的NH2末端片段从膜释放并行进到细胞核以激活其参与抗病毒反应的靶基因。 这些假设将通过提案中提出的三个具体目标进行检验。特异性目的1将确定HCV复制刺激CREB3L1切割的机制。我们将研究HCV编码的膜蛋白表达诱导的ER应激是否触发CREB3L1的切割。具体目标2将确定CREB3L1的S1P和S2P催化的裂解是否是其抗病毒功能所必需的。主要的方法是制造不能被这些蛋白酶切割的CREB3L1突变体，并检查突变对其抗病毒功能的影响。特异性目标3将通过微阵列分析鉴定抑制HCV复制的CREB3L1靶基因。如果这些具体目标得以实现，我们将提供新的信息，这将大大提高我们对先天免疫反应的理解。这一新的知识可能揭示治疗HCV感染的新的药物靶点。 公共卫生关系：该项目旨在研究一种名为CREB3L1的细胞蛋白介导的新型抗病毒反应，该蛋白可有效抑制丙型肝炎病毒（HCV）复制。HCV感染全球1.7亿人，病毒感染是美国肝功能衰竭的主要原因。目前基于干扰素的HCV感染治疗仅具有部分感染性。因此，了解CREB3L1介导的抗病毒途径，这显然是干扰素的非依赖性，可能会揭示急需的新策略来治疗HCV感染。