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

基本信息

批准号：
8683078
负责人：
JIN YE
金额：
$ 39.35万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
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

项目摘要

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.

描述（由申请人提供）：丙型肝炎病毒 (HCV) 感染世界人口的 3%，并导致大多数慢性肝病病例。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导致耐药病毒株的快速出现，因此很难开发针对HCV蛋白的药物。目前 HCV 感染的治疗基于干扰素，它介导针对 RNA 病毒感染的先天免疫反应。然而，这种治疗仅部分有效。因此，了解其他先天抗病毒反应可能会揭示治疗 HCV 感染急需的新策略。我们最近发现了一种新型先天抗病毒反应，它在限制人类肝癌细胞系中的丙型肝炎病毒感染方面发挥着重要作用。该通路由 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，其合成为插入内质网 (ER) 中的膜结合前体，并通过称为调节膜内蛋白水解 (RIP) 的过程激活。根据我们目前对 RIP 的理解，我们认为 HCV 在 ER 中的复制会导致 CREB3L1 被 Site-1 蛋白酶 (S1P) 和 Site-2 蛋白酶 (S2P) 裂解。蛋白水解裂解使 CREB3L1 的 NH2 末端片段从膜上释放并进入细胞核，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。具体目标 1 将确定 HCV 复制刺激 CREB3L1 裂解的机制。我们将检查 HCV 编码膜蛋白表达诱导的 ER 应激是否触发 CREB3L1 的裂解。具体目标 2 将确定 CREB3L1 的抗病毒功能是否需要 S1P 和 S2P 催化的裂解。主要方法是制备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。具体目标 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，从而显着增强我们对先天免疫反应的理解。这一新知识可能会揭示治疗丙型肝炎病毒感染的新药物靶点。