Eukaryotic Heme Utilization

真核血红素利用

• 批准号: 7734202
• 负责人: Caroline Philpott
• 金额: $ 36.54万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7734202
• 关键词: Ataxia; Binding; Biochemical Genetics; Biological; Caenorhabditis elegans; Cell membrane; Cells; Collaborations; Condition; Copper; Enzymes; Eukaryota; Eukaryotic Cell; Exhibits; Genes; Genetic; Heme; Heme Iron; Hemoglobin; Hereditary Disease; Hereditary hemochromatosis; Homeostasis; Human; Hypoxia; Intracellular Transport; Iron; Iron Compounds; Iron Overload; Mammals; Maryland; Metabolism; Microarray Analysis; Myoglobin; Numbers; Nutrient; Organic Iron Compounds; Organism; Oxygen; Porphyrins; Process; Regulation; Role; Saccharomyces cerevisiae; Saccharomycetales; System; Toxin; Universities; Yeasts; Zinc; cofactor; deprivation; heme a; human disease; insight; iron metabolism; loss of function; metal metabolism; microorganism; mutant; protoporphyrin IX; response; uptake

Very little is known about heme transport in eukaryotes and a heme-specific transport uptake systems have not been identified in yeast. Although S. cerevisiae does not take up heme in response to iron deprivation, we have determined that this species does have an inducible heme uptake system that is activated under heme deficiency and hypoxic conditions. We performed microarray analysis of strains grown under these conditions, and found that a number of putative transporters are transcriptionally activated. We have identified transporters that, when over expressed, increase heme uptake into yeast. We have also identified a transporter, termed PUG1 (Porphyrin uptake gene 1), that stimulates the uptake of protoporphyrin IX, the immediate precursor of heme, and simultaneously inhibits the utilization of heme. This transporter is transcriptionally activated by oxygen and heme deficiency and is expressed on the plasma membrane of yeast. In collaboration with Iqbal Hamza of the University of Maryland, we are functionally characterizing the putative heme transporters of C. elegans by expressing them in yeast. Heme transporters from C. elegans have heme uptake activity when expressed in yeast and mutant forms of heme transporters exhibit loss of function when expressed in yeast.

关于真核生物中血红素的转运知之甚少，并且尚未在酵母中鉴定出血红素特异性转运摄取系统。尽管酿酒酵母不会因缺铁而摄取血红素，但我们已经确定该物种确实具有在血红素缺乏和缺氧条件下激活的诱导型血红素摄取系统。我们对在这些条件下生长的菌株进行了微阵列分析，发现许多假定的转运蛋白被转录激活。我们已经确定了转运蛋白，当过度表达时，会增加酵母对血红素的吸收。我们还发现了一种转运蛋白，称为 PUG1（卟啉摄取基因 1），它可以刺激原卟啉 IX（血红素的直接前体）的摄取，同时抑制血红素的利用。这种转运蛋白因氧和血红素缺乏而被转录激活，并在酵母的质膜上表达。 我们与马里兰大学的 Iqbal Hamza 合作，通过在酵母中表达线虫的假定血红素转运蛋白来对其进行功能表征。来自线虫的血红素转运蛋白在酵母中表达时具有血红素摄取活性，而突变形式的血红素转运蛋白在酵母中表达时表现出功能丧失。