Iron response element

About: Iron response element is a research topic. Over the lifetime, 84 publications have been published within this topic receiving 13375 citations. The topic is also known as: IRE.

Cloning and characterization of a mammalian proton-coupled metal-ion transporter

Abstract: Metal ions are essential cofactors for a wealth of biological processes, including oxidative phosphorylation, gene regulation and free-radical homeostasis. Failure to maintain appropriate levels of metal ions in humans is a feature of hereditary haemochromatosis, disorders of metal-ion deficiency, and certain neurodegenerative diseases. Despite their pivotal physiological roles, however, there is no molecular information on how metal ions are actively absorbed by mammalian cells. We have now identified a new metal-ion transporter in the rat, DCT1, which has an unusually broad substrate range that includes Fe2+, Zn2+, Mn2+, Co2+, Cd2+, Cu2+, Ni2+ and Pb2+. DCT1 mediates active transport that is proton-coupled and depends on the cell membrane potential. It is a 561-amino-acid protein with 12 putative membrane-spanning domains and is ubiquitously expressed, most notably in the proximal duodenum. DCT1 is upregulated by dietary iron deficiency, and may represent a key mediator of intestinal iron absorption. DCT1 is a member of the 'natural-resistance-associated macrophage protein' (Nramp) family and thus its properties provide insight into how these proteins confer resistance to pathogens.

Molecular control of vertebrate iron metabolism: mRNA-based regulatory circuits operated by iron, nitric oxide, and oxidative stress

Abstract: As an essential nutrient and a potential toxin, iron poses an exquisite regulatory problem in biology and medicine. At the cellular level, the basic molecular framework for the regulation of iron uptake, storage, and utilization has been defined. Two cytoplasmic RNA-binding proteins, iron-regulatory protein-1 (IRP-1) and IRP-2, respond to changes in cellular iron availability and coordinate the expression of mRNAs that harbor IRP-binding sites, iron-responsive elements (IREs). Nitric oxide (NO) and oxidative stress in the form of H2O2 also signal to IRPs and thereby influence cellular iron metabolism. The recent discovery of two IRE-regulated mRNAs encoding enzymes of the mitochondrial citric acid cycle may represent the beginnings of elucidating regulatory coupling between iron and energy metabolism. In addition to providing insights into the regulation of iron metabolism and its connections with other cellular pathways, the IRE/IRP system has emerged as a prime example for the understanding of translational regulation and mRNA stability control. Finally, IRP-1 has highlighted an unexpected role for iron sulfur clusters as post-translational regulatory switches.

Microcytic anaemia mice have a mutation in Nramp2, a candidate iron transporter gene.

Abstract: Although disorders of iron metabolism are prevalent, iron transport remains poorly understood. To address this problem, we undertook a positional cloning strategy to identify the causative mutation in mice with microcytic anaemia (mk). Homozygous mk/mk mice have microcytic, hypochromic anaemia due to severe defects in intestinal iron absorption and erythroid iron utilization1–4. We report the identification of a strong candidate gene for mk, and suggest that the phenotype is a consequence of a missense mutation in Nramp2 (ref. 5), a previously identified gene of unknown function. Nramp2 is homologous to Nrampl, a gene active in host defense. If Nramp2 is mk, as the cumulative evidence suggests, our findings have broad implications for the understanding of iron transport and resistance to intracellular pathogens.