Iron uptake in mammalian cells has been extensively
investigated and has revealed a post-transcriptional control mechanism
regulating the transferrin receptor and ferritin synthesis. Cytosolic iron is
strictly controlled, with most of the spare iron being stored as ferritin in a
non-reactive form.
However, the distribution of cellular iron is
still unresolved. In
particular, little is known about iron localization in the nucleus. This is an
important question, given the fact that the process of DNA oxidation by
oxy-radicals is catalyzed by nuclear iron, which can produces DNA strand breaks
even in the presence of physiological concentrations of hydrogen peroxide.
Nuclear iron has been found in several forms, either
associated with ferritin as a heme complex that regulates gene expression, or
in the nucleus in the form of iron-sulfur clusters associated with DNA repair
enzymes and transcription factors.
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