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Tob38, a novel essential component in the biogenesis of β‐barrel proteins of mitochondria
Author(s) -
Waizenegger Thomas,
Habib Shukry J,
Lech Maciej,
Mokranjac Dejana,
Paschen Stefan A,
Hell Kai,
Neupert Walter,
Rapaport Doron
Publication year - 2004
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.7400183
Subject(s) - biogenesis , bacterial outer membrane , microbiology and biotechnology , translocase of the outer membrane , mitochondrion , translocase of the inner membrane , mitochondrial membrane transport protein , mitochondrial carrier , organelle biogenesis , biology , inner mitochondrial membrane , inner membrane , membrane protein , chemistry , biochemistry , membrane , escherichia coli , gene
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.