Thioredoxin Activation of Iron Regulatory Proteins

Iron regulatory proteins (IRP1 and IRP2) are redox-sensitive RNA-binding proteins that modulate the expression of several genes encoding key proteins of iron metabolism. IRP1 can also exist as an aconitase containing a [4Fe-4S] cluster bound to three cysteines at the active site. We previously showed that biosynthesis of nitric oxide (NO) induces the transition of IRP1 from aconitase to apoprotein able to bind RNA. This switch is also observed when cytosolic extracts are exposed to NO donors. However, the activation of IRP1 under these conditions is far from maximal. In this study we examined the capacity of physiological reducing systems to cooperate with NO in the activation of IRP1. Cytosolic extracts from the macrophage cell line RAW 264.7 or purified IRP1 were incubated with NO donors and subsequently exposed to glutathione or to thioredoxin (Trx), a strong protein disulfide reductase. Trx was the most effective, inducing a 2–6-fold enhancement of the RNA binding activity of NO-treated IRP1. Furthermore, the effect of NO on IRP1 from cytosolic extracts was abolished in the presence of anti-Trx antibodies. We also studied the combined effect of NO and Trx on IRP2, which exhibits constitutive RNA binding activity. We observed an inhibition of IRP2 activity following exposure to NO donors which was restored by Trx. Collectively, these results point to a crucial role of Trx as a modulator of IRP activity in situations of NO production.

[1]  J. Connor,et al.  Abnormal localization of iron regulatory protein in Alzheimer's disease , 1998, Brain Research.

[2]  D. Taramelli,et al.  Nitric oxide-mediated induction of ferritin synthesis in J774 macrophages by inflammatory cytokines: role of selective iron regulatory protein-2 downregulation. , 1998, Blood.

[3]  A. Holmgren,et al.  Inhibition of AP-1 DNA binding by nitric oxide involving conserved cysteine residues in Jun and Fos. , 1998, Biochemical and biophysical research communications.

[4]  R. Eisenstein,et al.  Iron regulatory protein 1 is not required for the modulation of ferritin and transferrin receptor expression by iron in a murine pro-B lymphocyte cell line. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[5]  J. Drapier,et al.  Redox Modulation of Iron Regulatory Proteins by Peroxynitrite* , 1997, The Journal of Biological Chemistry.

[6]  M. Kennedy,et al.  The iron-sulfur cluster of iron regulatory protein 1 modulates the accessibility of RNA binding and phosphorylation sites. , 1997, Biochemistry.

[7]  J. Phillips,et al.  Expression and biochemical characterization of iron regulatory proteins 1 and 2 in Saccharomyces cerevisiae. , 1996, Biochemistry.

[8]  K. Umesono,et al.  Thioredoxin: a redox-regulating cellular cofactor for glucocorticoid hormone action. Cross talk between endocrine control of stress response and cellular antioxidant defense system. , 1996, The Journal of clinical investigation.

[9]  E. Block,et al.  Nitric oxide-induced inhibition of lung endothelial cell nitric oxide synthase via interaction with allosteric thiols: role of thioredoxin in regulation of catalytic activity. , 1996, American journal of respiratory cell and molecular biology.

[10]  G. Minotti,et al.  Superoxide and hydrogen peroxide‐dependent inhibition of iron regulatory protein activity: a protective stratagem against oxidative injury , 1996, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[11]  B. Henderson.  Iron regulatory proteins 1 and 2 , 1996, BioEssays : news and reviews in molecular, cellular and developmental biology.

[12]  B. Polla,,et al.  Dual regulation of heat-shock transcription factor (HSF) activation and DNA-binding activity by H2O2: role of thioredoxin. , 1996, The Biochemical journal.

[13]  A. Holmgren,et al.  S-Nitrosoglutathione Is Cleaved by the Thioredoxin System with Liberation of Glutathione and Redox Regulating Nitric Oxide* , 1996, The Journal of Biological Chemistry.

[14]  C. Sen,et al.  Antioxidant and redox regulation of gene transcription , 1996, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[15]  R. Eisenstein,et al.  Phosphorylation and Activation of both Iron Regulatory Proteins 1 and 2 in HL-60 Cells (*) , 1996, The Journal of Biological Chemistry.

[16]  J. Drapier,et al.  Modulation of Iron Regulatory Protein Functions , 1996, The Journal of Biological Chemistry.

[17]  R. Klausner,et al.  Requirements for iron‐regulated degradation of the RNA binding protein, iron regulatory protein 2. , 1995, The EMBO journal.

[18]  J. Phillips,et al.  Iron Regulates the Intracellular Degradation of Iron Regulatory Protein 2 by the Proteasome (*) , 1995, The Journal of Biological Chemistry.

[19]  G. Cairo,et al.  Nitric-oxide-mediated activation of iron-regulatory protein controls hepatic iron metabolism during acute inflammation. , 1995, European journal of biochemistry.

[20]  L. Kühn,et al.  Differential Modulation of the RNA-binding Proteins IRP-1 and IRP-2 in Response to Iron , 1995, The Journal of Biological Chemistry.

[21]  K. Bridges,et al.  Ascorbic Acid Enhances Ferritin mRNA Translation by an IRP/Aconitase Switch (*) , 1995, The Journal of Biological Chemistry.

[22]  J. Phillips,et al.  Characterization and Expression of Iron Regulatory Protein 2 (IRP2). , 1995, The Journal of Biological Chemistry.

[23]  M. Hentze,et al.  Rapid responses to oxidative stress mediated by iron regulatory protein. , 1995, The EMBO journal.

[24]  M. Radman,et al.  Mismatch Binding Protein-Based Mutation Detection Systems , 1995 .

[25]  J. Beckman,et al.  Sensitivity of the essential zinc-thiolate moiety of yeast alcohol dehydrogenase to hypochlorite and peroxynitrite. , 1995, Biochemistry.

[26]  R. Klausner,et al.  Translational Repressor Activity Is Equivalent and Is Quantitatively Predicted by in Vitro RNA Binding for Two Iron-responsive Element-binding Proteins, IRP1 and IRP2 (*) , 1995, The Journal of Biological Chemistry.

[27]  S. Snyder,et al.  The iron-responsive element binding protein: a target for synaptic actions of nitric oxide. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[28]  R. Klausner,et al.  Molecular characterization of a second iron-responsive element binding protein, iron regulatory protein 2. Structure, function, and post-translational regulation. , 1994, The Journal of biological chemistry.

[29]  B. Guo,et al.  Iron regulates cytoplasmic levels of a novel iron-responsive element-binding protein without aconitase activity. , 1994, The Journal of biological chemistry.

[30]  N. Gray,et al.  Iron regulatory protein prevents binding of the 43S translation pre‐initiation complex to ferritin and eALAS mRNAs. , 1994, The EMBO journal.

[31]  R D Klausner,et al.  Evidence that the pathway of transferrin receptor mRNA degradation involves an endonucleolytic cleavage within the 3′ UTR and does not involve poly(A) tail shortening. , 1994, The EMBO journal.

[32]  K. Schulze-Osthoff,et al.  Distinct effects of thioredoxin and antioxidants on the activation of transcription factors NF-kappa B and AP-1. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[33]  L. Kühn,et al.  Mutational analysis of the [4Fe‐4S]‐cluster converting iron regulatory factor from its RNA‐binding form to cytoplasmic aconitase. , 1994, EMBO Journal.

[34]  L. Kühn,et al.  Characterization of a second RNA-binding protein in rodents with specificity for iron-responsive elements. , 1993, The Journal of biological chemistry.

[35]  R. Eisenstein,et al.  Iron-responsive element-binding protein. Phosphorylation by protein kinase C. , 1993, The Journal of biological chemistry.

[36]  H. Beinert,et al.  Aconitase, a two‐faced protein: enzyme and iron regulatory factor 1 2 , 1993, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[37]  G Werner-Felmayer,et al.  Translational regulation via iron‐responsive elements by the nitric oxide/NO‐synthase pathway. , 1993, The EMBO journal.

[38]  J. Drapier,et al.  Biosynthesis of nitric oxide activates iron regulatory factor in macrophages. , 1993, The EMBO journal.

[39]  R. Klausner,et al.  Modification of a free Fe-S cluster cysteine residue in the active iron-responsive element-binding protein prevents RNA binding. , 1993, The Journal of biological chemistry.

[40]  R. Klausner,et al.  Regulating the fate of mRNA: The control of cellular iron metabolism , 1993, Cell.

[41]  H. Beinert,et al.  Purification and characterization of cytosolic aconitase from beef liver and its relationship to the iron-responsive element binding protein , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[42]  R. Klausner,et al.  Cellular regulation of the iron-responsive element binding protein: disassembly of the cubane iron-sulfur cluster results in high-affinity RNA binding. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[43]  L. Kühn,et al.  In vivo and in vitro modulation of the mRNA-binding activity of iron-regulatory factor. Tissue distribution and effects of cell proliferation, iron levels and redox state. , 1992, European journal of biochemistry.

[44]  T. Curran,et al.  Redox activation of Fos‐Jun DNA binding activity is mediated by a DNA repair enzyme. , 1992, The EMBO journal.

[45]  M. Hentze,et al.  Coordination of cellular iron metabolism by post-transcriptional gene regulation. , 1992, Journal of inorganic biochemistry.

[46]  N. Gray,et al.  Identification of a novel iron‐responsive element in murine and human erythroid delta‐aminolevulinic acid synthase mRNA. , 1991, The EMBO journal.

[47]  T. Cox,et al.  Human erythroid 5‐aminolevulinate synthase: promoter analysis and identification of an iron‐responsive element in the mRNA. , 1991, The EMBO journal.

[48]  B. Freeman,et al.  Peroxynitrite oxidation of sulfhydryls. The cytotoxic potential of superoxide and nitric oxide. , 1991, The Journal of biological chemistry.

[49]  Barbara Neupert,et al.  A specific mRNA binding factor regulates the iron-dependent stability of cytoplasmic transferrin receptor mRNA , 1989, Cell.

[50]  R D Klausner,et al.  Oxidation-reduction and the molecular mechanism of a regulatory RNA-protein interaction. , 1989, Science.

[51]  H. Munro,et al.  Cytoplasmic protein binds in vitro to a highly conserved sequence in the 5' untranslated region of ferritin heavy- and light-subunit mRNAs. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[52]  V. Pigiet,et al.  Thioredoxin-catalyzed refolding of disulfide-containing proteins. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[53]  Theil Ec,et al.  The iron responsive element (IRE) family of mRNA regulators. Regulation of iron transport and uptake compared in animals, plants, and microorganisms. , 1998 .

[54]  H. Nakamura,et al.  Redox regulation of cellular activation. , 1997, Annual review of immunology.

[55]  J. Drapier,et al.  Aconitases: a class of metalloproteins highly sensitive to nitric oxide synthesis. , 1996, Methods in enzymology.

[56]  E. A. Martins,et al.  Oxidative stress induces activation of a cytosolic protein responsible for control of iron uptake. , 1995, Archives of biochemistry and biophysics.

[57]  R. Klausner,et al.  A double life: cytosolic aconitase as a regulatory RNA binding protein. , 1993, Molecular biology of the cell.