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

描述（由申请人提供）：许多不同的疾病是由内质网（ER应激）中未折叠蛋白过量引起的。内质网应激诱导未折叠蛋白反应（UPR），其中许多保护性基因被激活。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。虽然已经确定了三个典型的UPR转录因子，但我们已经确定秀丽隐杆线虫的转录因子SKN-1（哺乳动物Nrf1/2/3）也是UPR的核心。SKN-1在氧化应激防御中具有保守功能，并且在长寿中很重要。我们已经证明SKN-1受UPR调控，内质网应激需要SKN-1激活核心UPR调控因子以及下游效应基因。令人惊讶的是，SKN-1响应氧化应激需要UPR信号，这表明内质网信号可能广泛影响细胞应激防御，并可能在胰岛素- igf -1样信号（IIS）和TOR（雷帕霉素靶点）途径中调节SKN-1。利用强大的秀丽隐线虫模型，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如何受到UPR的调节，以及(3)在UPR期间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）方法将被用于研究SKN-1的功能是如何被UPR调节的，并在体内促进内质网抗逆性。经过验证的RNAi筛选策略将确定内质网胁迫下SKN-1的新调控因子，高通量测序结合表达谱分析和ChIP将用于鉴定SKN-1直接调控的基因和过程。这些研究将为内质网如何抵御压力提供重要而新颖的见解，并将实质性地改变理解内质网信号传导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.