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Updated: Jun 4, 2026

Electrophoretic Mobility Shift Assay (EMSA) for the Study of RNA-Protein Interactions: The IRE/IRP Example
Published on: December 3, 2014
Redox control of iron regulatory protein 2 stability
Anja Hausmann1, Julie Lee, Kostas Pantopoulos
1Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada.
Abstract:
Iron regulatory protein 2 (IRP2) is a critical switch for cellular and systemic iron homeostasis. In iron-deficient or hypoxic cells, IRP2 binds to mRNAs containing iron responsive elements (IREs) and regulates their expression. Iron promotes proteasomal degradation of IRP2 via the F-box protein FBXL5. Here, we explored the effects of oxygen and cellular redox status on IRP2 stability. We show that iron-dependent decay of tetracycline-inducible IRP2 proceeds efficiently under mild hypoxic conditions (3% oxygen) but is compromised in severe hypoxia (0.1% oxygen). A treatment of cells with exogenous H(2)O(2) protects IRP2 against iron and increases its IRE-binding activity. IRP2 is also stabilized during menadione-induced oxidative stress. These data demonstrate that the degradation of IRP2 in iron-replete cells is not only oxygen-dependent but also sensitive to redox perturbations.
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Regulation of the Unfolded Protein Response
Redox Reactions
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Protein Modifications in the RER
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.
