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Ferritin L and H subunits are differentially regulated on a post‐transcriptional level
Author(s) -
Sammarco Mimi C.,
Ditch Scott,
Banerjee Ayan,
Grabczyk Ed
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.998.3
Subject(s) - ferritin , transcriptional regulation , microbiology and biotechnology , protein subunit , biological pathway , biology , endogeny , gene expression , chemistry , gene , biochemistry
Ferritin plays a key role in the storage and release of iron. The protein is a multimer composed of 24 ferritin L (FTL) and ferritin H (FTH) subunits, in ratios that vary in different cell types. Because the subunits are not functionally interchangeable, both L and H units are critical for maintaining iron homeostasis and protecting against iron overload. FTL and FTH are regulated primarily at a post‐transcriptional level in response to cellular iron. Individual regulation of FTL and FTH is of much interest, and although transcriptional differences between FTL and FTH have been shown, differences in their post‐transcriptional regulation have not been evaluated. We report here that FTL and FTH are differentially regulated in 1% oxygen on a post‐transcriptional level. We have designed a novel cell‐based assay system, sensitive enough to detect differences between FTL and FTH iron regulatory elements (IREs) that a standard electrophoretic mobility shift assay does not. The FTL IRE is the primary responder in the presence of an iron donor in hypoxic conditions, and this response is reflected in endogenous FTL protein levels. These results provide evidence that FTL and FTH subunits respond independently to cellular iron concentrations and underscore the importance of evaluating FTL and FTH IREs separately.