Regulation Of Metabolism And Gene Expression By Iron-Sulfur Clusters - Resubmission - 1

铁硫簇（ISCs）是一种重要的蛋白质辅因子，其调节异常与包括弗里德希共济失调在内的多种衰弱性疾病有关。这种病理学部分是由于在铁响应蛋白（IRP）中使用ISC，IRP控制铁饥饿反应中mRNA的翻译。我们最近发现，通过抑制ISC的生物合成，我们可以有力地激活这种IRP介导的铁饥饿反应，使癌细胞对铁凋亡引起的细胞死亡敏感。我们的初步数据，这形成了我们的应用程序的前提，指出了一个意想不到的模式的IRP 2调控的ISCs和证明，ISCs调节铁饥饿反应，从而影响人类疾病的机制，仍然不清楚。我们的长期目标是剖析ISCs调节细胞对铁和氧可用性变化的反应的机制，以及这种反应如何由IRP介导。我们预计，这些发现将导致识别疾病的病理先前的ISC参与是不清楚的，新的治疗疾病的ISC失调，并将促进新的方法，使癌细胞敏感的ferroptosis。这项资助的目的是剖析ISCs如何控制IRP 2的激活，并全面定义IRP 1和IRP 2的目标以及它们被激活的条件。我们的总体假设是，ISCs整合铁和氧水平的输入，以影响特定的翻译反应，通过差异调节IRP。我们的基本原理是，识别IRP被激活的特定机制和它们激活的靶点将能够发现治疗癌症和ISC代谢紊乱的新策略。我们的具体目标将测试以下假设：（目的1）ISCs可以通过IRP 2介导的机制激活铁饥饿反应;（目的2）IRP表现出差异IRE结合响应铁和氧水平的调节。完成这些目标后，我们将（1）了解细胞如何感知铁和氧水平，并使用ISC传感器整合这些输入，（2）识别IRP调节的靶基因及其调节条件。这一贡献是重要的，因为IRP的失调经常发生在人类病理学中，并且诱导铁饥饿反应的激活使癌细胞对铁凋亡细胞死亡敏感。这项研究是创新的，因为我们挑战细胞铁传感的范式，以达到一个全面的机制，细胞响应这种重要营养素水平的变化，因为我们利用迄今为止独特的方法来识别由铁饥饿反应调节的RNA，并定义其激活上游刺激。这项研究的结果有望打破我们对铁传感的理解，并对治疗癌症以及与铁代谢和储存缺陷相关的人类疾病具有广泛的意义。

Iron-sulfur clusters (ISCs) are essential protein cofactors whose dysregulation is linked to a wide range of debilitating diseases including Friedrch’s ataxia. This pathology is due in part to the use of ISCs in iron-responsive proteins (IRPs), which control the translation of mRNAs in the iron-starvation response. We recently found that by suppressing ISC biosynthesis we can robustly activate this IRP-mediated iron-starvation response, sensitizing cancer cells to cell death by ferroptosis. Our preliminary data, which form the premise of our application, point to an unexpected mode of IRP2 regulation by ISCs and demonstrate that the mechanism by which ISCs modulate the iron-starvation response, and therefore impact human disease, remains unclear. Our long-term goal is to dissect the mechanisms by which ISCs regulates cellular responses to changing iron and oxygen availability and how this response is mediated by IRPs. We anticipate that these discoveries will lead to the identification of pathologies for diseases where prior ISC involvement was unclear, to new treatments for diseases of ISC dysregulation, and will facilitate novel methods to sensitize cancer cells to ferroptosis. The objective of this grant is to dissect how ISCs control IRP2 activation and to comprehensively define the targets of IRP1 and IRP2 and the conditions under which they are activated. Our overarching hypothesis is that ISCs integrate iron and oxygen level inputs to effect specific translational responses via differential regulation of IRPs. Our rationale is that identification of the specific mechanisms by which IRPs are activated and the targets that they activate will enable the discovery of novel strategies to treat cancer and disorders of ISC metabolism. Our specific aims will test the following hypotheses: (Aim 1) ISCs can activate the iron-starvation response through an IRP2-mediated mechanism; (Aim 2) IRPs exhibit differential IRE binding in response to iron and oxygen level modulation. Upon completion of these aims we will (1) gain an understanding of how cells sense iron and oxygen levels and integrate these inputs using ISC sensors and (2) identify IRP regulated target genes and the conditions in which they are regulated. This contribution is significant because dysregulation of IRPs occurs frequently in human pathologies and inducing activation of the iron starvation response sensitizes cancer cells to ferroptotic cell death. This research is innovative because we challenge paradigms in cellular iron-sensing to arrive at a comprehensive mechanism by which cells respond to changes in the level of this important nutrient, and because we utilize heretofore unique approaches to identify RNAs regulated by the iron starvation response and define their activation by upstream stimuli. The outcomes of this study promise disrupt our understanding of iron sensing and have broad implications for the treatment of cancer as well as human diseases related to defects in iron metabolism and storage.