Regulation of heme synthesis by mitochondrial proteins

线粒体蛋白对血红素合成的调节

• 批准号: 10540604
• 负责人: Yvette Y Yien
• 金额: $ 39.13万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10540604
• 关键词: Regulation; heme; synthesis; mitochondrial; proteins

ABSTRACT The long-term goal of this project is to identify the mechanisms that regulate “housekeeping” mitochondrial heme metabolism. Heme plays a central role in the redox reactions of life-essential processes such as mitochondrial respiration. My research program is particularly interested in 1. identifying proteins that regulate mitochondrial heme/porphyrin transport and 2. proteins that are part of the housekeeping mitochondrial homeostasis machinery that structurally or functionally interact with the core enzymes of the heme synthesis pathway. While the enzymes of the heme synthesis are well characterized and identical in all tissues, the regulatory mechanisms that couple heme synthesis to cellular requirements are very poorly understood. The importance of these regulatory mechanisms is underscored by the existence of disorders of heme synthesis and iron metabolism that are caused by dysregulation of proteins that are commonly associated with “housekeeping” homeostatic processes or mitochondrial respiration. Although all tissues require heme, most of our studies on regulatory aspects of heme synthesis have focused on erythroid cells to the exclusion of understanding heme synthesis in other cell types. This project uses our knowledge of erythroid heme synthesis as a springboard to identify heme regulatory mechanisms that are required for housekeeping heme synthesis. Project 1 aims to identify proteins that are required for mitochondrial porphyrin transport in non-erythroid cells. Heme intermediates are photosensitive and cytotoxic, requiring mechanisms for cells to quickly and efficiently transport heme intermediates across cell membranes, to the next enzyme in the heme synthetic pathway. When efficient transport does not occur, cytotoxic porphyrins accumulate in cells, potentially causing porphyria and heme deficiency. While TMEM14C is essential for porphyrin transport in erythroid cells, TMEM14 proteins are not required for heme synthesis in non-erythroid cells. Using a combination of proteomics and whole genome sequencing/RNAseq analysis of TMEM14C suppressor mutants, we will identify novel mitochondrial proteins that regulate porphyrin transport in non-erythroid cells. The long-term goal of Project 2 is to understand the regulation of the heme synthesis complex by proteins that regulate housekeeping mitochondrial homeostasis. During this project period, we focus on the ubiquitous mitochondrial unfoldase, CLPX, which plays an essential role in regulating the activity and protein stability of heme synthesis enzymes. We show that the function of CLPX is highly tissue-specific, and propose to understand its role in the systemic regulation of heme metabolism in the setting of “housekeeping” heme synthesis. These studies will provide essential datasets that will be invaluable to the mitochondrial protein unfoldase community, but will also be essential for determining how CLPX globally regulates mitochondrial homeostasis via tight regulation of heme.

摘要 这个项目的长期目标是确定调节“管家”线粒体的机制。 血红素代谢。血红素在生命必备过程的氧化还原反应中起着核心作用，如 线粒体呼吸作用。我的研究项目对1.鉴定蛋白质特别感兴趣 调节线粒体血红素/卟啉转运和2.作为管家一部分的蛋白质 线粒体动态平衡机制在结构上或功能上与细胞的核心酶相互作用 血红素合成途径。虽然血红素合成的酶有很好的特性，而且在所有方面都是相同的 组织中，将血红素合成与细胞需求相结合的调节机制非常差。 明白了。这些调节机制的重要性被存在的障碍所突显 血红素合成和铁代谢是由常见相关蛋白质的失调引起的 有“管家”的动态平衡过程或线粒体呼吸。尽管所有的组织都需要血红素， 我们对血红素合成的调节方面的大部分研究都集中在红系细胞上，而不是 了解其他细胞类型中的血红素合成。这个项目利用我们对红血球血红素合成的知识。 作为一个跳板，以确定内务血红素合成所需的血红素调节机制。 项目1旨在确定在非红系中线粒体卟啉运输所需的蛋白质 细胞。血红素中间体是光敏和细胞毒性的，需要细胞快速和 有效地将血红素中间体穿过细胞膜，输送到合成的血红素中的下一个酶 路径。当没有发生有效的转运时，细胞毒性的卟啉会在细胞内积累，可能会导致 卟啉症和血红素缺乏症。虽然TMEM14C对卟啉在红系细胞中的转运是必不可少的， TMEM14蛋白不是非红系细胞合成血红素所必需的。使用以下组合 TMEM14C抑制突变体的蛋白质组学和全基因组测序/RNAseq分析，我们将鉴定 调节非红系细胞中卟啉转运的新型线粒体蛋白。的长期目标是 项目2是了解调节家务的蛋白质对血红素合成复合体的调节。 线粒体动态平衡。在这个项目期间，我们专注于普遍存在的线粒体展开酶， CLPX在调节血红素合成酶的活性和蛋白质稳定性方面起着至关重要的作用。 我们证明了CLPX的功能是高度组织特异性的，并建议了解它在全身 “管家”式的血红素合成中的血红素代谢调节。这些研究将提供 对线粒体蛋白展开酶群落非常有价值的基本数据集，但也将是 对于确定CLPX如何通过对血红素的严格调控来全球调节线粒体的动态平衡至关重要。