Iron chaperones PCBP1 and PCBP2 mediate the metallation of the dinuclear iron enzyme deoxyhypusine hydroxylase

Avery G. Frey, Anjali Nandal, Jong Hwan Park, Pamela M. Smith, Toshiki Yabe, Moon Suhn Ryu, Manik C. Ghosh, Jaekwon Lee, Tracey A. Rouault, Myung Hee Park, Caroline C. Philpott

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

Although cells express hundreds of metalloenzymes, the mechanisms by which apoenzymes receive their metal cofactors are largely unknown. Poly(rC)-binding proteins PCBP1 and PCBP2 are multifunctional adaptor proteins that bind iron and deliver it to ferritin for storage or to prolyl and asparagyl hydroxylases to metallate the mononuclear iron center. Here, we show that PCBP1 and PCBP2 also deliver iron to deoxyhypusine hydroxylase (DOHH), the dinuclear iron enzyme required for hypusine modification of the translation factor eukaryotic initiation factor 5A. Cells depleted of PCBP1 or PCBP2 exhibited loss of DOHH activity and loss of the holo form of the enzyme in cells, particularly when cells were made mildly iron-deficient. Lysates containing PCBP1 and PCBP2 converted apo-DOHH to holo-DOHH in vitro with greater efficiency than lysates lacking PCBP1 or PCBP2. PCBP1 bound to DOHH in iron-treated cells but not in control or iron-deficient cells. Depletion of PCBP1 or PCBP2 had no effect on the cytosolic Fe-S cluster enzyme xanthine oxidase but led to loss of cytosolic aconitase activity. Loss of aconitase activity was not accompanied by gain of RNA-binding activity, a pattern suggesting the incomplete disassembly of the [4Fe-4S] cluster. PCBP depletions had minimal effects on total cellular iron, mitochondrial iron levels, and heme synthesis. Thus, PCBP1 and PCBP2 may serve as iron chaperones to multiple classes of cytosolic nonheme iron enzymes and may have a particular role in restoring metal cofactors that are spontaneously lost in iron deficient cells.

Original languageEnglish (US)
Pages (from-to)8031-8036
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number22
DOIs
StatePublished - Jun 3 2014

Keywords

  • Diiron enzyme
  • Iron regulatory protein

ASJC Scopus subject areas

  • General

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    Frey, A. G., Nandal, A., Park, J. H., Smith, P. M., Yabe, T., Ryu, M. S., Ghosh, M. C., Lee, J., Rouault, T. A., Park, M. H., & Philpott, C. C. (2014). Iron chaperones PCBP1 and PCBP2 mediate the metallation of the dinuclear iron enzyme deoxyhypusine hydroxylase. Proceedings of the National Academy of Sciences of the United States of America, 111(22), 8031-8036. https://doi.org/10.1073/pnas.1402732111