Journal of Biochemistry Advance Access originally published online on August 31, 2009
Journal of Biochemistry 2009 146(5):599-608; doi:10.1093/jb/mvp133
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JB Minireview-Quality Control of the Cellular Protein Systems |
Disulphide Bond Formation in the Intermembrane Space of Mitochondria
Butenandt Institute for Physiological Chemistry, Ludwig-Maximilians University, D-81377 Munich, Germany
*To whom correspondence should be addressed. Tel: +49-89-2180-77100, Fax: +49-89-2180-77093, E-mail: hell{at}med.uni-muenchen.de
Received May 19, 2009; Accepted May 27, 2009
| Abstract |
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Proteins of the intermembrane space (IMS) of mitochondria fulfil crucial functions in cellular processes, such as transport of proteins and metal ions, ATP production and apoptotic cell death. All IMS proteins are synthesized in the cytosol and then transported across the mitochondrial outer membrane. A subset of these proteins contains disulphide bonds. For their import into the IMS, they employ a disulphide relay system, made up of two essential proteins, Mia40/Tim40 and the flavin-dependent sulfhydryl-electron transferase Erv1. The disulphide relay system introduces disulphide bonds in substrate proteins triggering their folding. The oxidative folding traps substrates in the IMS and thereby drives their net import into the IMS. Thus, protein import is coupled to oxidative protein folding, maybe providing a first control of protein quality. Here, we review the current knowledge about the Erv1-Mia40 system and address aspects that require further consideration.
Key Words: disulphide bond formation, Erv1, intermembrane space, Mia40, protein import
Abbreviations: ALR, augmenter of liver regeneration; AtErv1, Erv1 from Arabidopsis thaliana; CTC, charge-transfer complex; Ccs1, copper chaperone for Sod1; Cyt c, cytochrome c; DTT, dithiothreitol; DsbB, disulphide bond formation protein B; ER, endoplasmic reticulum; Erv, essential for respiration and vegetative growth in yeast; GR, glutathione reductase; IMS, intermembrane space; LipDH, dihydrolipoamide dehydrogenase; Mia, mitochondrial intermembrane space import and assembly; QSOX, quiescin-sulfhydryl oxidase; Trx, thioredoxin; TrxR, thioredoxin reductase; Sod1, copper/zinc superoxide dismutase; Tim, translocase of the inner membrane; TOM, translocase of the outer membrane; twin Cx3,9C-motif, twin Cx3C-motif or twin Cx9C-motif