Essential mitochondrial role in iron-sulfur cluster assembly of the cytoplasmic isopropylmalate isomerase Leu1 in Saccharomyces cerevisiae

Ashutosh K. Pandey, Jayashree Pain, Brindha J, Andrew Dancis, Debkumar Pain

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Iron-sulfur (Fe-S) cluster assembly in mitochondria and cytoplasm is essential for cell viability. In the yeast S. cerevisiae, Leu1 [4Fe-4S] is the cytoplasmic isopropylmalate isomerase involved in leucine biosynthesis. Using permeabilized Δleu1 cells and recombinant apo-Leu1R, here we show that the [4Fe-4S] cluster assembly on Leu1R can be reconstituted in a physiologic manner requiring both mitochondria and cytoplasm, as judged by conversion of the inactive enzyme to an active form. The mitochondrial contribution to this reconstitution assay is abrogated by inactivating mutations in the mitochondrial ISC (iron-sulfur cluster assembly) machinery components (such as Nfs1 cysteine desulfurase and Ssq1 chaperone) or the mitochondrial exporter Atm1. Likewise, depletion of a CIA (cytoplasmic iron-sulfur protein assembly) component Dre2 leads to impaired Leu1R reconstitution. Mitochondria likely make and export an intermediate, called X-S or (Fe-S)int, that is needed for cytoplasmic Fe-S cluster biosynthesis. Here we show that once exported, the same intermediate can be used for both [2Fe-2S] and [4Fe-4S] cluster biogenesis in the cytoplasm, with no further requirement of mitochondria. Our data also suggest that the exported intermediate can activate defective/latent CIA components in cytoplasm isolated from nfs1 or Δatm1 mutant cells. These findings may provide a way to isolate X-S or (Fe-S)int.

Original languageEnglish (US)
Pages (from-to)104-115
Number of pages12
JournalMitochondrion
Volume69
DOIs
StatePublished - Mar 2023
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Molecular Biology
  • Cell Biology

Keywords

  • Cytoplasm
  • Fe-S cluster assembly
  • Iron-sulfur intermediate
  • Mitochondria
  • Mitochondrial export
  • Permeabilized cells

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