Iron homeostasis in the fission yeast Schizosaccharomyces pombe
Iron homeostasis in the fission yeast Schizosaccharomyces pombe
复制标题
DOI：
10.1007/s10534-006-9056-5
复制
发表时间：
2007-06-01
期刊：
影响因子：
3.5
通讯作者：
Mercier, Alexandre
中科院分区：
文献类型：
--
作者：
Labbe, Simon;Pelletier, Benoit;Mercier, Alexandre
粟酒裂殖酵母具有铁的获取过程，铁是一种必需的营养素。一种途径包括产生、排泄和捕获铁载体-铁复合物。第二种途径需要在细胞表面的三价铁被渗透酶-氧化酶复合物摄取之前进行酶促还原。编码铁同化蛋白的基因受铁利用率的转录调控。在高铁条件下，GATA型调节因子Fep 1抑制铁吸收基因的表达。Fep 1的阻遏物功能需要Tup 11或Tup 12转录辅阻遏物的存在。在低铁条件下，发生两种调节机制。首先，铁转运基因是高度诱导的。第二，有一个转录因子级联，涉及异聚体CCAAT结合复合物，关闭一组编码铁利用蛋白的基因，大概是为了避免在产生铁利用蛋白时无用的能量消耗，这些蛋白缺乏必要的辅因子来发挥作用。因此，总的来说，这些对铁浓度变化的调节反应确保铁存在于细胞内用于基本的生化反应，但防止铁或铁使用蛋白质积累到有害水平。
Schizosaccharomyces pombe has acquisition processes for iron, an essential nutrient. One pathway consists to produce, excrete, and capture siderophore-iron complexes. A second pathway requires enzymatic reduction of ferric iron at the cell surface prior to uptake by a permease-oxidase complex. Genes encoding proteins involved in iron assimilation are transcriptionally regulated as a function of iron availability. Under high iron conditions, the GATA-type regulator Fep1 represses the expression of iron uptake genes. The repressor function of Fep1 requires the presence of the Tup11 or Tup12 transcriptional co-repressor. Under low iron conditions, two regulatory mechanisms occur. First, the iron transport genes are highly induced. Second, there is a transcription factor cascade implicating the heteromeric CCAAT-binding complex that turns off a set of genes encoding iron-utilizing proteins, presumably to avoid a futile expenditure of energy in producing iron-using proteins that lack the necessary cofactor to function. Thus, collectively, these regulatory responses to variations in iron concentrations ensure that iron is present within cells for essential biochemical reactions, yet prevent the accumulation of iron or iron-using proteins to deleterious levels.