Published:
Springer Science and Business Media LLC, 2004
Published in:
EMBO reports, 5 (2004) 7, Seite 704-709
Language:
English
DOI:
10.1038/sj.embor.7400183
ISSN:
1469-221X;
1469-3178
Origination:
Footnote:
Description:
Insertion of β‐barrel proteins into the outer membrane of mitochondria is mediated by the TOB complex. Known constituents of this complex are Tob55 and Mas37. We identified a novel component, Tob38. It is essential for viability of yeast and the function of the TOB complex. Tob38 is exposed on the surface of the mitochondrial outer membrane. It interacts with Mas37 and Tob55 and is associated with Tob55 even in the absence of Mas37. The Tob38–Tob55 core complex binds precursors of β‐barrel proteins and facilitates their insertion into the outer membrane. Depletion of Tob38 results in strongly reduced levels of Tob55 and Mas37 and the residual proteins no longer form a complex. Tob38‐depleted mitochondria are deficient in the import of β‐barrel precursor proteins, but not of other outer membrane proteins or proteins of other mitochondrial subcompartments. We conclude that Tob38 has a crucial function in the biogenesis of β‐barrel proteins of mitochondria.