Proteins iron-regulatory

How Does NO and H2O2 Affect the Iron Regulatory Proteins IRP-1 and IRP-2... 

In the EPR of mammalian cells, we do not see much in addition to the signals from the respiratory complexes. The enzyme aconitase from the citric-acid cycle can be detected, and also the protein cytoplasmic aconitase, later identified as the mRNA translation regulatory factor iron regulatory protein IRP-1, which actually started its career in biochemistry as an EPR signal that could not be assigned to the respiratory chain (Kennedy et al. 1992). 

BSA was oxidized by the cupric quercetin complex probably through binding to tryptophan residue [26]. Iwai et al. [27] showed that the iron regulatory protein 2 (IRP2) responsible... 

Wallander, M.L., Leibold, E.A. and Eisenstein, R.S. (2006) Molecular control of vertebrate iron homeostasis by iron regulatory proteins, Biochim. Biophys. Acta, 1763, 668-689. 

The X-ray structures of other aconitases have appeared in the literature. Recently, the crystal structure of human iron regulatory protein, IRPl, in its aconitase form, has been published. Iron regulatory proteins (IRPs) control the translation of proteins involved in iron uptake, storage, and utilization by binding to specific noncoding sequences of the corresponding mRNAs known... 

Magaki et al. [2007] measured the levels of loosely bound, nonheme, and total iron and copper in the frontal cortex and hippocampus of patients with mild-moderate AD (n = 3), severe AD (n = 8), and dementia with Lewy bodies (DLB, n = 6). Additionally, the expression of iron regulatory protein 2 (IRP2) was examined in relation to the pathological hallmarks of AD, that is, 5 amyloid plaques, neurofibrillary tangles (NFT), and Lewy bodies. A significant decrease of loosely bound iron was found in the hippocampal white matter of both mild-moderate and severe AD patients and a trend toward increased... 

Magaki S, Raghavan R, Mueller C, Oberg KC, Vinters HV, Kirsch WM. 2007. Iron, copper, and iron regulatory protein 2 in Alzheimer s disease and related dementias. Neurosci Lett 418 72-76. 

NADH, reduced nicotinamide-adenine dinueleotide Q, coenzyme Q FNR, fumarate nitrate reduction SoxR, superoxide activated regulatory protein IRP, iron regulatory protein NIFU, nitrogen fixation gene U product. 

Relatively recently Fe/S proteins have been found to function in the regulation of biosynthesis. This can be by promoting deoxyribonucleic acid (DNA) transcription, e.g. the [2Fe-2S] containing Escherichia coli superoxide-activated (SoxR) transcription activator [10-12], or the presumably [4Fe-4S]-containing E. coli transcription factor fumarate nitrate reduction (FNR) [13,14], Alternatively, the Fe/S protein can act by interference with messenger ribonucleic acid (mRNA) translation, i.e., the iron regulatory proteins (IRPs) [15,16], These interactions are stoichiometric, therefore not catalytic. Presumably, they are also a form of sensoring, namely, of oxidants and/or iron [17],... 

Keywords Aluminum, Iron, Transferrin, Iron regulatory protein, Alzheimer s disease... 

Effect of Al on Iron Regulatory Protein-1 and -2 in Mammalian Cells... 

Iron regulatory proteins (IRPs) regulate the cellular iron level in mammalian cells. IRPs are known as cytosol mRNA binding proteins which control the stability or the translation rate of mRNAs of iron metabolism-related proteins such as TfR, ferritin, and 5-aminolevulinic acid synthetase in response to the availability of cellular iron [19-21] after uptake [5]. The regulatory mechanism involves the interaction between the iron-responsive element (IRE) in the 3 or 5 untranslated regions of the transcripts and cytosolic IRPs (IRP-1 and -2). IRP-1 is an iron-sulfur (Fe-S) protein with aconitase activity containing a cubane 4Fe-4S cluster. When Fe is replete, IRP-1 prevails in a 4Fe-4S form as a holo-form and is an active cytoplasmic aconitase. As shown in Fig. 3, when Fe is deplete, it readily loses one Fe from the fourth labile Fe in the Fe-S cluster to become a 3Fe-4S cluster and in this state has little enzymatic activity [22, 23]. 

Iron regulatory protein-1 (IRP-1) Iron sensor (cytosol aconitase)... 

Fig. 3. Effect of aluminum on post-transcriptional regulation by iron regulatory protein-1...

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