de Llanos Rosa, Martínez-Garay Carlos Andrés, Fita-Torró Josep, Romero Antonia María, Martínez-Pastor María Teresa, Puig Sergi
Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain.
Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Valencia, Spain.
Appl Environ Microbiol. 2016 May 2;82(10):3052-3060. doi: 10.1128/AEM.00305-16. Print 2016 May 15.
Fungi, including the yeast Saccharomyces cerevisiae, lack ferritin and use vacuoles as iron storage organelles. This work explored how plant ferritin expression influenced baker's yeast iron metabolism. Soybean seed ferritin H1 (SFerH1) and SFerH2 genes were cloned and expressed in yeast cells. Both soybean ferritins assembled as multimeric complexes, which bound yeast intracellular iron in vivo and, consequently, induced the activation of the genes expressed during iron scarcity. Soybean ferritin protected yeast cells that lacked the Ccc1 vacuolar iron detoxification transporter from toxic iron levels by reducing cellular oxidation, thus allowing growth at high iron concentrations. Interestingly, when simultaneously expressed in ccc1Δ cells, SFerH1 and SFerH2 assembled as heteropolymers, which further increased iron resistance and reduced the oxidative stress produced by excess iron compared to ferritin homopolymer complexes. Finally, soybean ferritin expression led to increased iron accumulation in both wild-type and ccc1Δ yeast cells at certain environmental iron concentrations.
Iron deficiency is a worldwide nutritional disorder to which women and children are especially vulnerable. A common strategy to combat iron deficiency consists of dietary supplementation with inorganic iron salts, whose bioavailability is very low. Iron-enriched yeasts and cereals are alternative strategies to diminish iron deficiency. Animals and plants possess large ferritin complexes that accumulate, detoxify, or buffer excess cellular iron. However, the yeast Saccharomyces cerevisiae lacks ferritin and uses vacuoles as iron storage organelles. Here, we explored how soybean ferritin expression influenced yeast iron metabolism, confirming that yeasts that express soybean seed ferritin could be explored as a novel strategy to increase dietary iron absorption.
真菌，包括酿酒酵母，缺乏铁蛋白，并利用液泡作为铁储存细胞器。这项工作探索了植物铁蛋白表达如何影响面包酵母的铁代谢。大豆种子铁蛋白H1（SFerH1）和SFerH2基因被克隆并在酵母细胞中表达。两种大豆铁蛋白都组装成多聚体复合物，在体内结合酵母细胞内的铁，因此诱导了铁缺乏时表达的基因的激活。大豆铁蛋白通过减少细胞氧化，保护缺乏Ccc1液泡铁解毒转运蛋白的酵母细胞免受有毒铁水平的影响，从而使其能够在高铁浓度下生长。有趣的是，当在ccc1Δ细胞中同时表达时，SFerH1和SFerH2组装成杂聚物，与铁蛋白同聚物复合物相比，这进一步提高了铁抗性并降低了过量铁产生的氧化应激。最后，在特定环境铁浓度下，大豆铁蛋白表达导致野生型和ccc1Δ酵母细胞中铁积累增加。
缺铁是一种全球范围内的营养紊乱，妇女和儿童尤其易受影响。对抗缺铁的一种常见策略是通过饮食补充无机铁盐，但其生物利用度非常低。富含铁的酵母和谷物是减少缺铁的替代策略。动物和植物拥有大型铁蛋白复合物，可积累、解毒或缓冲细胞内过量的铁。然而，酿酒酵母缺乏铁蛋白，并利用液泡作为铁储存细胞器。在这里，我们探索了大豆铁蛋白表达如何影响酵母铁代谢，证实了表达大豆种子铁蛋白的酵母可作为一种增加膳食铁吸收的新策略进行探索。
