Preprotein transport machineries of yeast mitochondrial outer membrane are not required for Bax-induced release of intermembrane space proteins |
| |
Authors: | Sanjuán Szklarz Luiza K Kozjak-Pavlovic Vera Vögtle F-Nora Chacinska Agnieszka Milenkovic Dusanka Vogel Sandra Dürr Mark Westermann Benedikt Guiard Bernard Martinou Jean-Claude Borner Christoph Pfanner Nikolaus Meisinger Chris |
| |
Affiliation: | Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Universit?t Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany. |
| |
Abstract: | The mitochondrial outer membrane contains protein import machineries, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It has been speculated that TOM or SAM are required for Bax-induced release of intermembrane space (IMS) proteins; however, experimental evidence has been scarce. We used isolated yeast mitochondria as a model system and report that Bax promoted an efficient release of soluble IMS proteins while preproteins were still imported, excluding an unspecific damage of mitochondria. Removal of import receptors by protease treatment did not inhibit the release of IMS proteins by Bax. Yeast mutants of each Tom receptor and the Tom40 channel were not impaired in Bax-induced protein release. We analyzed a large collection of mutants of mitochondrial outer membrane proteins, including SAM, fusion and fission components, but none of these components was required for Bax-induced protein release. The released proteins included complexes up to a size of 230 kDa. We conclude that Bax promotes efficient release of IMS proteins through the outer membrane of yeast mitochondria while the inner membrane remains intact. Inactivation of the known protein import and sorting machineries of the outer membrane does not impair the function of Bax at the mitochondria. |
| |
Keywords: | CCHL, cytochrome c heme lyase Δψ, membrane potential IMS, intermembrane space Mcr1, mitochondrial NADH-cytochrome b5 reductase MIA, mitochondrial intermembrane space import and assembly PVDF, polyvinylidene difluoride SAM, sorting and assembly machinery of outer mitochondrial membrane TIM, translocase of inner mitochondrial membrane TOM, translocase of outer mitochondrial membrane |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|