Role of twin Cys-Xaa9-Cys motif cysteines in mitochondrial import of the cytochrome c oxidase biogenesis factor Cmc1

Myriam Bourens, Deepa V. Dabir, Heather L. Tienson, Irina Sorokina, Carla M. Koehler, Antoni Barrientos

Research output: Contribution to journalArticle

13 Scopus citations


The Mia40 import pathway facilitates the import and oxidative folding of cysteine-rich protein substrates into the mitochondrial intermembrane space. Here we describe the in vitro and in organello oxidative folding of Cmc1, a twin CX9C-containing substrate, which contains an unpaired cysteine. In vitro, Cmc1 can be oxidized by the import receptor Mia40 alone when in excess or at a lower rate by only the sulfhydryl oxidase Erv1. However, physiological and efficient Cmc1 oxidation requires Erv1 and Mia40. Cmc1 forms a stable intermediate with Mia40 and is released from this interaction in the presence of Erv1. The three proteins are shown to form a ternary complex in mitochondria. Our results suggest that this mechanism facilitates efficient formation of multiple disulfides and prevents the formation of non-native disulfide bonds.

Original languageEnglish (US)
Pages (from-to)31258-31269
Number of pages12
JournalJournal of Biological Chemistry
Issue number37
StatePublished - Sep 7 2012


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this