Regulation of C. elegans SKN-1/Nrf activity by the unfolded protein response

描述(申请人提供)：许多不同的疾病由内质网中过量的未折叠蛋白引起(内质网应激)。内质网应激诱导未折叠蛋白应答(UPR)，其中许多保护基因被激活。了解UPR如何防御内质网应激，以及UPR信号如何影响其他细胞过程是至关重要的。虽然已经鉴定了三个典型的UPR转录因子，但我们在线虫中确定了转录因子SKN-1(哺乳动物的Nrf1/2/3)也是UPR的中心。SKN-1在氧化应激防御中具有保守功能，对长寿具有重要作用。我们已经证明SKN-1受UPR调控，并且是内质网应激激活核心UPR调节因子以及下游效应基因所必需的。令人惊讶的是，SKN-1需要UPR信号来响应氧化应激，这表明ER信号可能广泛地影响细胞的应激防御，并可能在胰岛素-IGF-1样信号(IIS)和TOR(雷帕霉素的靶标)途径中调节SKN-1。利用功能强大的线虫模型，本项目将研究：(1)SKN-1如何以及在哪些组织中防御内质网应激，以及IIS和TOR如何通过SKN-1影响内质网应激抗性，(2)在内质网应激、氧化应激以及IIS和TOR途径的背景下，SKN-1如何受UPR调控，以及(3)在UPR过程中，SKN-1直接控制哪些基因和生物过程。转基因、遗传、分子、细胞生物学和染色质免疫沉淀(ChIP)方法将被用来研究SKN-1功能如何受到UPR的调控并在体内参与内质网应激抵抗。经过验证的RNAi筛选策略将在内质网应激期间识别SKN-1的新调节因子，并将使用高通量测序结合表达谱和芯片来识别由SKN-1直接调控的基因和过程。这些研究将为内质网如何防御应激提供重要而新颖的见解，并将极大地改变理解基于内质网的信号及其如何影响其他细胞防御机制的范式。

DESCRIPTION (provided by applicant): Many diverse diseases arise from an excess of unfolded proteins in the endoplasmic reticulum (ER stress). ER stress induces the unfolded protein response (UPR), in which numerous protective genes are activated. It is critical to understand how the UPR defends against ER stress, and how UPR signaling affects other cellular processes. While three canonical UPR transcription factors have been identified, we have determined in C. elegans that the transcription factor SKN-1 (mammalian Nrf1/2/3) is also central to the UPR. SKN-1 has a conserved function in oxidative stress defense, and is important in longevity. We have shown that SKN-1 is regulated by the UPR, and is needed for ER stress to activate core UPR regulators, as well as downstream effector genes. Surprisingly, UPR signaling is required for SKN-1 to respond to oxidative stress, which suggests that ER signaling may broadly influence cellular stress defenses, and may regulate SKN-1 in the insulin-IGF-1-like signaling (IIS) and TOR (target of rapamycin) pathways. Using the powerful C. elegans model, this project will investigate: (1) how and in what tissues SKN-1 defends against ER stress, and how IIS and TOR might affect ER stress resistance through SKN-1, (2) how SKN-1 is regulated by the UPR during ER stress, oxidative stress, and in the context of the IIS and TOR pathways, and (3) what genes and biological processes are controlled directly by SKN-1 during the UPR. Transgenic, genetic, molecular, cell biological, and chromatin immunoprecipitation (ChIP) approaches will be used to investigate how SKN-1 functions are regulated by the UPR and contribute to ER stress resistance in vivo. A proven RNAi screening strategy will identify new regulators of SKN-1 during ER stress, and high-throughput sequencing combined with expression profiling and ChIP will be employed to identify genes and processes regulated directly by SKN-1. These studies will provide important and novel insights into how the ER defends itself against stress, and will substantially alter paradigms for understanding ER-based signaling and how it influences other cellular defense mechanisms.