Unexpected Anthracycline-Mediated Alterations in Iron-Regulatory Protein-RNA-Binding Activity: The Iron and Copper Complexes of Anthracyclines Decrease RNA-Binding Activity

2002 ◽  
Vol 62 (4) ◽  
pp. 888-900 ◽  
Author(s):  
Juliana C. Kwok ◽  
Des R. Richardson
Keyword(s):  
Copper Complexes ◽  
Rna Binding ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Iron Regulatory Protein

scholarly journals Cysteine Oxidation Regulates the RNA-Binding Activity of Iron Regulatory Protein 2

2009 ◽  
Vol 29 (8) ◽  
pp. 2219-2229 ◽  
Author(s):  
Kimberly B. Zumbrennen ◽  
Michelle L. Wallander ◽  
S. Joshua Romney ◽  
Elizabeth A. Leibold
Keyword(s):  
Oxidative Stress ◽  
Transferrin Receptor ◽  
Iron Homeostasis ◽  
Rna Binding ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Structural Basis ◽  
Iron Regulatory Protein ◽  
Transferrin Receptor 1 ◽  
Binding Cleft

ABSTRACT Iron regulatory protein 2 (IRP2) is an RNA-binding protein that regulates the posttranscriptional expression of proteins required for iron homeostasis such as ferritin and transferrin receptor 1. IRP2 RNA-binding activity is primarily regulated by iron-mediated proteasomal degradation, but studies have suggested that IRP2 RNA binding is also regulated by thiol oxidation. We generated a model of IRP2 bound to RNA and found that two cysteines (C512 and C516) are predicted to lie in the RNA-binding cleft. Site-directed mutagenesis and thiol modification show that, while IRP2 C512 and C516 do not directly interact with RNA, both cysteines are located within the RNA-binding cleft and must be unmodified/reduced for IRP2-RNA interactions. Oxidative stress induced by cellular glucose deprivation reduces the RNA-binding activity of IRP2 but not IRP2-C512S or IRP2-C516S, consistent with the formation of a disulfide bond between IRP2 C512 and C516 during oxidative stress. Decreased IRP2 RNA binding is correlated with reduced transferrin receptor 1 mRNA abundance. These studies provide insight into the structural basis for IRP2-RNA interactions and reveal an iron-independent mechanism for regulating iron homeostasis through the redox regulation of IRP2 cysteines.

scholarly journals TP53 Mutation Status Influences Iron Regulatory Protein RNA Binding Activity and Sensitivity to Ferroptotic Cell Death

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1277-1277
Author(s):  
Laurie Thompson ◽  
Thais Oliveira ◽  
Evan Hermann ◽  
Mckale Montgomery ◽  
Winyoo Chowanadisai ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Viability ◽  
Tp53 Mutation ◽  
Rna Binding ◽  
Human Cancer ◽  
Regulatory Protein ◽  
Tp53 Gene ◽  
Binding Activity ◽  
Iron Regulatory Protein ◽  
Mutation Status

Abstract Objectives The tumor suppressor gene TP53 is the most commonly mutated gene in human cancer, but mutations in TP53 do not just result in loss of tumor suppressor function, they can also promote cancer progression by altering cellular iron acquisition and metabolism. A newly identified role for TP53 in the mediation of iron homeostasis and cancer cell survival lies in the ability for TP53 to protect against ferroptosis, a form of iron mediated cell death. The purpose of this study was to determine the extent to which TP53 mutation status effects iron-mediated cell death in response to ferroptosis induction. We also measured TP53 dependent differences in iron regulatory protein (IRP) RNA binding activity to begin to clarify the mechanisms by which TP53 mutation status may influence sensitivity to ferroptosis. Methods Using H1299 cells, which are null for TP53, we generated cell lines expressing either a tetracycline inducible wild-type TP53 gene, or a representative mutated TP53 gene from exemplary “hotspot” mutations in the DNA binding domain (R248, R273, R282, G245, R249 and R175). These six mutation types were selected because they represent 25% of all TP53 mutations in human cancer. To determine the influence of TP53 mutation status on sensitivity to ferroptotic cell death, we treated cells with erastin, a potent inducer of ferroptosis and measured differences in cell viability between these cell lines using PrestoBlue cell viability reagent. To assess mutant TP53-depenent differences in IRP RNA binding activity during ferroptosis we measured differences in IRP RNA binding activity via Electrophoretic Mobility-Shift Assay. Results We found that TP53 mutants (R273, R248, R175, G245, and R249) were significantly less viable (P < 0.05) after initiation of ferroptosis compared to cells expressing WT TP53. Following ferroptosis induction, we observed a significant (P < 0.05) increase in IRP RNA binding in G245, R248, and R175 mutants. Conclusions Our preliminary analyses indicate that TP53 mutants may be more sensitive to ferroptosis, but IRPs do not seem to be solely responsible for the increase in iron during ferroptotic cell death. Furthermore, ferroptosis may be a potential therapeutic target for cancers with these TP53 mutations but further investigation is warranted. Funding Sources Internal funding at Oklahoma State University.

scholarly journals Distinct TP53 Mutation Types Exhibit Increased Sensitivity to Ferroptosis Independently of Changes in Iron Regulatory Protein Activity

2020 ◽  
Vol 21 (18) ◽  
pp. 6751
Author(s):  
Laurie R. Thompson ◽  
Thais G. Oliveira ◽  
Evan R. Hermann ◽  
Winyoo Chowanadisai ◽  
Stephen L. Clarke ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Suppressor ◽  
Tp53 Mutation ◽  
Rna Binding ◽  
Iron Acquisition ◽  
Regulatory Protein ◽  
Tp53 Gene ◽  
Iron Regulatory Protein ◽  
Regulatory Pathways ◽  
Increased Sensitivity

The tumor suppressor gene TP53 is the most commonly mutated gene in human cancer. In addition to loss of tumor suppressor functions, mutations in TP53 promote cancer progression by altering cellular iron acquisition and metabolism. A newly identified role for TP53 in the coordination of iron homeostasis and cancer cell survival lies in the ability for TP53 to protect against ferroptosis, a form of iron-mediated cell death. The purpose of this study was to determine the extent to which TP53 mutation status affects the cellular response to ferroptosis induction. Using H1299 cells, which are null for TP53, we generated cell lines expressing either a tetracycline inducible wild-type (WT) TP53 gene, or a representative mutated TP53 gene from six exemplary “hotspot” mutations in the DNA binding domain (R273H, R248Q, R282W, R175H, G245S, and R249S). TP53 mutants (R273H, R248Q, R175H, G245S, and R249S) exhibited increased sensitivity ferroptosis compared to cells expressing WT TP53. As iron-mediated lipid peroxidation is critical for ferroptosis induction, we hypothesized that iron acquisition pathways would be upregulated in mutant TP53-expressing cells. However, only cells expressing the R248Q, R175H, and G245S TP53 mutation types exhibited statistically significant increases in spontaneous iron regulatory protein (IRP) RNA binding activity following ferroptosis activation. Moreover, changes in the expression of downstream IRP targets were inconsistent with the observed differences in sensitivity to ferroptosis. These findings reveal that canonical iron regulatory pathways are bypassed during ferroptotic cell death. These results also indicate that induction of ferroptosis may be an effective therapeutic approach for tumor cells expressing distinct TP53 mutation types.

The Iron-Sulfur Cluster of Iron Regulatory Protein 1 Modulates the Accessibility of RNA Binding and Phosphorylation Sites†

Biochemistry ◽  
1997 ◽  
Vol 36 (13) ◽  
pp. 3950-3958 ◽  
Author(s):  
Kevin L. Schalinske ◽  
Sheila A. Anderson ◽  
Polygena T. Tuazon ◽  
Opal S. Chen ◽  
M. Claire Kennedy ◽  
...  
Keyword(s):  
Rna Binding ◽  
Regulatory Protein ◽  
Phosphorylation Sites ◽  
Iron Regulatory Protein ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Iron Regulatory Protein 1

Effects of iron regulatory protein regulation on iron homeostasis during hypoxia

Blood ◽  
2003 ◽  
Vol 102 (9) ◽  
pp. 3404-3411 ◽  
Author(s):  
Brian D. Schneider ◽  
Elizabeth A. Leibold
Keyword(s):  
Iron Uptake ◽  
Iron Homeostasis ◽  
Rna Binding ◽  
Late Phase ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Iron Regulatory Proteins ◽  
Ft Synthesis

AbstractIron regulatory proteins (IRP1 and IRP2) are RNA-binding proteins that affect the translation and stabilization of specific mRNAs by binding to stem-loop structures known as iron responsive elements (IREs). IREs are found in the 5′-untranslated region (UTR) of ferritin (Ft) and mitochondrial aconitase (m-Aco) mRNAs, and in the 3′-UTR of transferrin receptor (TfR) and divalent metal transporter-1 (DMT1) mRNAs. Our previous studies show that besides iron, IRPs are regulated by hypoxia. Here we describe the consequences of IRP regulation and show that iron homeostasis is regulated in 2 phases during hypoxia: an early phase where IRP1 RNA-binding activity decreases and iron uptake and Ft synthesis increase, and a late phase where IRP2 RNA-binding activity increases and iron uptake and Ft synthesis decrease. The increase in iron uptake is independent of DMT1 and TfR, suggesting an unknown transporter. Unlike Ft, m-Aco is not regulated during hypoxia. During the late phase of hypoxia, IRP2 RNA-binding activity increases, becoming the dominant regulator responsible for decreasing Ft synthesis. During reoxygenation (ReO2), Ft protein increases concomitant with a decrease in IRP2 RNA-binding activity. The data suggest that the differential regulation of IRPs during hypoxia may be important for cellular adaptation to low oxygen tension.

scholarly journals Recycling of RNA Binding Iron Regulatory Protein 1 into an Aconitase after Nitric Oxide Removal Depends on Mitochondrial ATP

2002 ◽  
Vol 277 (34) ◽  
pp. 31220-31227 ◽  
Author(s):  
Cécile Bouton ◽  
Marie-Jeanne Chauveau ◽  
Sylvie Lazereg ◽  
Jean-Claude Drapier
Keyword(s):  
Nitric Oxide ◽  
Rna Binding ◽  
Regulatory Protein ◽  
Iron Regulatory Protein ◽  
Oxide Removal ◽  
Nitric Oxide Removal ◽  
Iron Regulatory Protein 1
Sign in / Sign up

Export Citation Format

Share Document