scholarly journals Zinc Deficiency-induced Iron Accumulation, a Consequence of Alterations in Iron Regulatory Protein-binding Activity, Iron Transporters, and Iron Storage Proteins

2007 ◽  
Vol 283 (8) ◽  
pp. 5168-5177 ◽  
Author(s):  
Brad J. Niles ◽  
Michael S. Clegg ◽  
Lynn A. Hanna ◽  
Susan S. Chou ◽  
Tony Y. Momma ◽  
...  
Keyword(s):  
Protein Binding ◽  
Zinc Deficiency ◽  
Storage Proteins ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Iron Accumulation ◽  
Iron Regulatory Protein ◽  
Iron Storage ◽  
Iron Storage Proteins

scholarly journals Distinct Effects of Escherichia coli,Pseudomonas aeruginosa and Staphylococcus aureus Cell Wall Component-Induced Inflammation on the Iron Metabolism of THP-1 Cells

2021 ◽  
Vol 22 (3) ◽  
pp. 1497
Author(s):  
Edina Pandur ◽  
Kitti Tamási ◽  
Ramóna Pap ◽  
Gergely Jánosa ◽  
Katalin Sipos
Keyword(s):  
Cell Wall ◽  
Inflammatory Cytokines ◽  
Iron Metabolism ◽  
Inflammatory Cytokine ◽  
Cytokine Production ◽  
Storage Proteins ◽  
Iron Storage ◽  
E Coli ◽  
Iron Storage Proteins ◽  
Pro Inflammatory Cytokines

Macrophages are essential immune cells of the innate immune system. They participate in the development and regulation of inflammation. Macrophages play a fundamental role in fighting against bacterial infections by phagocytosis of bacteria, and they also have a specific role in immunomodulation by secreting pro-inflammatory cytokines. In bacterial infection, macrophages decrease the serum iron concentration by removing iron from the blood, acting as one of the most important regulatory cells of iron homeostasis. We examined whether the Gram-positive and Gram-negative cell wall components from various bacterial strains affect the cytokine production and iron transport, storage and utilization of THP-1 monocytes in different ways. We found that S. aureus lipoteichoic acid (LTA) was less effective in activating pro-inflammatory cytokine expression that may related to its effect on fractalkine production. LTA-treated cells increased iron uptake through divalent metal transporter-1, but did not elevate the expression of cytosolic and mitochondrial iron storage proteins, suggesting that the cells maintained iron efflux via the ferroportin iron exporter. E. coli and P. aeruginosa lipopolysaccharides (LPSs) acted similarly on THP-1 cells, but the rates of the alterations of the examined proteins were different. E. coli LPS was more effective in increasing the pro-inflammatory cytokine production, meanwhile it caused less dramatic alterations in iron metabolism. P. aeruginosa LPS-treated cells produced a smaller amount of pro-inflammatory cytokines, but caused remarkable elevation of both cytosolic and mitochondrial iron storage proteins and intracellular iron content compared to E. coli LPS. These results prove that LPS molecules from different bacterial sources alter diverse molecular mechanisms in macrophages that prepossess the outcome of the bacterial infection.

scholarly journals Functional homology between the yeast regulatory proteins GAL4 and LAC9: LAC9-mediated transcriptional activation in Kluyveromyces lactis involves protein binding to a regulatory sequence homologous to the GAL4 protein-binding site.

1987 ◽  
Vol 7 (12) ◽  
pp. 4400-4406 ◽  
Author(s):  
K D Breunig ◽  
P Kuger
Keyword(s):  
Protein Binding ◽  
Binding Site ◽  
Transcriptional Activation ◽  
Kluyveromyces Lactis ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Protein Binding Site ◽  
Regulatory Sequence ◽  
Functional Homology ◽  
Beta Galactosidase

As shown previously, the beta-galactosidase gene of Kluyveromyces lactis is transcriptionally regulated via an upstream activation site (UASL) which contains a sequence homologous to the GAL4 protein-binding site in Saccharomyces cerevisiae (M. Ruzzi, K.D. Breunig, A.G. Ficca, and C.P. Hollenberg, Mol. Cell. Biol. 7:991-997, 1987). Here we demonstrate that the region of homology specifically binds a K. lactis regulatory protein. The binding activity was detectable in protein extracts from wild-type cells enriched for DNA-binding proteins by heparin affinity chromatography. These extracts could be used directly for DNase I and exonuclease III protection experiments. A lac9 deletion strain, which fails to induce the beta-galactosidase gene, did not contain the binding factor. The homology of LAC9 protein with GAL4 (J.M. Salmeron and S. A. Johnston, Nucleic Acids Res. 14:7767-7781, 1986) strongly suggests that LAC9 protein binds directly to UASL and plays a role similar to that of GAL4 in regulating transcription.

The importance of eukaryotic ferritins in iron handling and cytoprotection

2015 ◽  
Vol 472 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Paolo Arosio ◽  
Fernando Carmona ◽  
Raffaella Gozzelino ◽  
Federica Maccarinelli ◽  
Maura Poli
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Animal Models ◽  
Storage Proteins ◽  
Eukaryotic Cells ◽  
Intracellular Iron ◽  
Iron Storage ◽  
Iron Incorporation ◽  
Iron Storage Proteins ◽  
Response Activation

Ferritins, the main intracellular iron storage proteins, have been studied for over 60 years, mainly focusing on the mammalian ones. This allowed the elucidation of the structure of these proteins and the mechanisms regulating their iron incorporation and mineralization. However, ferritin is present in most, although not all, eukaryotic cells, comprising monocellular and multicellular invertebrates and vertebrates. The aim of this review is to provide an update on the general properties of ferritins that are common to various eukaryotic phyla (except plants), and to give an overview on the structure, function and regulation of ferritins. An update on the animal models that were used to characterize H, L and mitochondrial ferritins is also provided. The data show that ferritin structure is highly conserved among different phyla. It exerts an important cytoprotective function against oxidative damage and plays a role in innate immunity, where it also contributes to prevent parenchymal tissue from the cytotoxicity of pro-inflammatory agonists released by the activation of the immune response activation. Less clear are the properties of the secretory ferritins expressed by insects and molluscs, which may be important for understanding the role played by serum ferritin in mammals.

scholarly journals PerR Controls Oxidative Stress Resistance and Iron Storage Proteins and Is Required for Virulence in Staphylococcus aureus

2001 ◽  
Vol 69 (6) ◽  
pp. 3744-3754 ◽  
Author(s):  
Malcolm J. Horsburgh ◽  
Mark O. Clements ◽  
Howard Crossley ◽  
Eileen Ingham ◽  
Simon J. Foster
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Stress Resistance ◽  
Iron Homeostasis ◽  
Storage Proteins ◽  
Iron Storage ◽  
Oxidative Stress Resistance ◽  
Genes Encoding ◽  
Starvation Survival ◽  
Iron Storage Proteins

ABSTRACT The Staphylococcus aureus genome encodes three ferric uptake regulator (Fur) homologues: Fur, PerR, and Zur. To determine the exact role of PerR, we inactivated the gene by allelic replacement using a kanamycin cassette, creating strain MJH001 (perR). PerR was found to control transcription of the genes encoding the oxidative stress resistance proteins catalase (KatA), alkyl hydroperoxide reductase (AhpCF), bacterioferritin comigratory protein (Bcp), and thioredoxin reductase (TrxB). Furthermore, PerR regulates transcription of the genes encoding the iron storage proteins ferritin (Ftn) and the ferritin-like Dps homologue, MrgA. Transcription of perR was autoregulated, and PerR repressed transcription of the iron homeostasis regulator Fur, which is a positive regulator of catalase expression. PerR functions as a manganese-dependent, transcriptional repressor of the identified regulon. Elevated iron concentrations produced induction of the PerR regulon. PerR may act as a peroxide sensor, since addition of external hydrogen peroxide to 8325-4 (wild type) resulted in increased transcription of most of the PerR regulon, except forfur and perR itself. The PerR-regulatedkatA gene encodes the sole catalase of S. aureus, which is an important starvation survival determinant but is surprisingly not required for pathogenicity in a murine skin abscess model of infection. In contrast, PerR is not necessary for starvation survival but is required for full virulence (P < 0.005) in this model of infection. PerR ofS. aureus may act as a redox sentinel protein during infection, analogous to the in vitro activities of OxyR and PerR ofEscherichia coli and Bacillus subtilis, respectively. However, it differs in its response to the metal balance within the cell and has the added capability of regulating iron uptake and storage.

Interaction of iron regulatory protein-1 (IRP-1) with ATP/ADP maintains a non-IRE-binding state

2010 ◽  
Vol 430 (2) ◽  
pp. 315-324 ◽  
Author(s):  
Zvezdana Popovic ◽  
Douglas M. Templeton
Keyword(s):  
Atpase Activity ◽  
Atp Hydrolysis ◽  
Binding Capacity ◽  
Regulatory Protein ◽  
Product Formation ◽  
Binding Activity ◽  
Hill Coefficient ◽  
Iron Regulatory Protein ◽  
Aconitase Activity ◽  
Iron Regulatory Protein 1

In its aconitase-inactive form, IRP-1 (iron regulatory protein-1)/cytosolic aconitase binds to the IRE (iron-responsive element) of several mRNAs to effect post-transcriptional regulation. We have shown previously that IRP-1 has ATPase activity and that binding of ATP suppresses the IRP-1/IRE interaction. In the present study, we characterize the binding activity further. Binding is observed with both [α-32P]ATP and [α-32P]ADP, but not with [γ-32P]ATP. Recombinant IRP-1 binds approximately two molecules of ATP, and positive co-operativity is observed with a Hill coefficient of 1.67±0.36 (EC50=44 μM) commencing at 1 μM ATP. Similar characteristics are observed with both apoprotein and the aconitase form. On binding, ATP is hydrolysed to ADP, and similar binding parameters and co-operativity are seen with ADP, suggesting that ATP hydrolysis is not rate limiting in product formation. The non-hydrolysable analogue AMP-PNP (adenosine 5′-[β,γ-imido]triphosphate) does not induce co-operativity. Upon incubation of IRP-1 with increasing concentrations of ATP or ADP, the protein migrates more slowly on agarose gel electrophoresis, and there is a shift in the CD spectrum. In this new state, adenosine nucleotide binding is competed for by other nucleotides (CTP, GTP and AMP-PNP), although ATP and ADP, but not the other nucleotides, partially stabilize the protein against spontaneous loss of aconitase activity when incubated at 37 °C. A mutant IRP-1(C437S) lacking aconitase activity shows only one ATP-binding site and lacks co-operativity. It has increased IRE-binding capacity and lower ATPase activity (Km=75±17 nmol/min per mg of protein) compared with the wild-type protein (Km=147±48 nmol/min per mg of protein). Under normal cellular conditions, it is predicted that ATP/ADP will maintain IRP-1 in a non-IRE-binding state.

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