Facile transfer of [2Fe-2S] clusters from the diabetes drug target mitoNEET to an apo-acceptor protein

John A. Zuris, Yael Harir, Andrea R. Conlan, Maya Shvartsman, Dorit Michaeli, Sagi Tamir, Mark L. Paddock, José N. Onuchic, Ron Mittler, Zvi Ioav Cabantchik, Patricia A. Jennings, Rachel Nechushtai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

MitoNEET (mNT) is an outer mitochondrial membrane target of the thiazolidinedione diabetes drugs with a unique fold and a labile [2Fe-2S] cluster. The rare 1-His and 3-Cys coordination of mNT's [2Fe-2S] leads to cluster lability that is strongly dependent on the presence of the single histidine ligand (His87). These properties of mNTare similar to known [2Fe-2S] shuttle proteins. Here we investigated whether mNT is capable of cluster transfer to acceptor protein(s). Facile [2Fe-2S] cluster transfer is observed between oxidized mNT and apo-ferredoxin (a-Fd) using UV-VIS spectroscopy and native-PAGE, as well as with a mitochondrial iron detection assay in cells. The transfer is unidirectional, proceeds to completion, and occurs with a second-order-reaction rate that is comparable to known iron-sulfur transfer proteins. Mutagenesis of His87 with Cys (H87C) inhibits transfer of the [2Fe-2S] clusters to a-Fd. This inhibition is beyond that expected fromincreased cluster kinetic stability, as the equivalently stable Lys55 to Glu (K55E) mutation did not inhibit transfer. The H87C mutant also failed to transfer its iron to mitochondria in HEK293 cells. The diabetes drug pioglitazone inhibits iron transfer from WT mNT to mitochondria, indicating that pioglitazone affects a specific property, [2Fe-2S] cluster transfer, in the cellular environment. This finding is interesting in light of the role of iron overload in diabetes. Our findings suggest a likely role for mNT in [2Fe-2S] and/or iron transfer to acceptor proteins and support the idea that pioglitazone's antidiabetic mode of action may, in part, be to inhibit transfer of mNT's [2Fe-2S] cluster.

Original languageAmerican English
Pages (from-to)13047-13052
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number32
DOIs
StatePublished - 9 Aug 2011

Keywords

  • CISD1
  • Diabetes
  • FeS cluster
  • Oxidative stress

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