The diabetes drug target MitoNEET governs a novel trafficking pathway to rebuild an Fe-S cluster into cytosolic aconitase/iron regulatory protein 1

J Biol Chem. 2014 Oct 10;289(41):28070-86. doi: 10.1074/jbc.M114.548438. Epub 2014 Jul 10.

Abstract

In eukaryotes, mitochondrial iron-sulfur cluster (ISC), export and cytosolic iron-sulfur cluster assembly (CIA) machineries carry out biogenesis of iron-sulfur (Fe-S) clusters, which are critical for multiple essential cellular pathways. However, little is known about their export out of mitochondria. Here we show that Fe-S assembly of mitoNEET, the first identified Fe-S protein anchored in the mitochondrial outer membrane, strictly depends on ISC machineries and not on the CIA or CIAPIN1. We identify a dedicated ISC/export pathway in which augmenter of liver regeneration, a mitochondrial Mia40-dependent protein, is specific to mitoNEET maturation. When inserted, the Fe-S cluster confers mitoNEET folding and stability in vitro and in vivo. The holo-form of mitoNEET is resistant to NO and H2O2 and is capable of repairing oxidatively damaged Fe-S of iron regulatory protein 1 (IRP1), a master regulator of cellular iron that has recently been involved in the mitochondrial iron supply. Therefore, our findings point to IRP1 as the missing link to explain the function of mitoNEET in the control of mitochondrial iron homeostasis.

Keywords: Fe-S Transfer; Iron Metabolism; Iron Regulatory Protein 1; Iron-Sulfur Protein; MitoNEET; Mitochondria; Nitric Oxide; Oxidative Stress; Protein Degradation; Small Interfering RNA (siRNA).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation
  • HeLa Cells
  • Hep G2 Cells
  • Homeostasis
  • Humans
  • Hydrogen Peroxide / chemistry
  • Iron / metabolism*
  • Iron Regulatory Protein 1 / chemistry*
  • Iron Regulatory Protein 1 / genetics
  • Iron Regulatory Protein 1 / metabolism
  • Mice
  • Mice, Transgenic
  • Mitochondria / chemistry
  • Mitochondria / metabolism*
  • Mitochondrial Membrane Transport Proteins / chemistry*
  • Mitochondrial Membrane Transport Proteins / genetics
  • Mitochondrial Membrane Transport Proteins / metabolism
  • Mitochondrial Membranes / chemistry
  • Mitochondrial Membranes / metabolism*
  • Mitochondrial Proteins / chemistry*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Nitric Oxide / chemistry
  • Oxidation-Reduction
  • Protein Folding
  • Protein Stability
  • Protein Structure, Tertiary
  • Protein Transport
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Signal Transduction

Substances

  • CHCHD4 protein, human
  • CISD1 protein, human
  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Proteins
  • Recombinant Proteins
  • Nitric Oxide
  • Hydrogen Peroxide
  • Iron
  • ACO1 protein, human
  • Iron Regulatory Protein 1