Milenkovic Dusanka, Kozjak Vera, Wiedemann Nils, Lohaus Christiane, Meyer Helmut E, Guiard Bernard, Pfanner Nikolaus, Meisinger Chris
Institut für Biochemie und Molekularbiologie, Universität Freiburg, D-79104 Freiburg, Germany.
J Biol Chem. 2004 May 21;279(21):22781-5. doi: 10.1074/jbc.C400120200. Epub 2004 Apr 2.
The mitochondrial outer membrane contains two integral proteins essential for cell viability, Tom40 of the translocase of the outer membrane (TOM complex) and Sam50 of the sorting and assembly machinery (SAM complex). Here we report the identification of Sam35, the first peripheral mitochondrial outer membrane protein that is essential for cell viability. Sam35 (encoded by the Saccharomyces cerevisiae ORF YHR083w) is a novel subunit of the SAM complex and is crucial for the assembly pathway of outer membrane beta-barrel proteins, such as the precursors of Tom40 and porin. Sam35 is not required for the import of inner membrane or matrix targeted proteins. The presence of two essential proteins in the SAM complex, Sam35 and Sam50, indicates that it plays a central role in mitochondrial biogenesis.
线粒体外膜包含两种对细胞生存能力至关重要的整合蛋白，即外膜转位酶（TOM复合物）的Tom40和分选与组装机器（SAM复合物）的Sam50。在此，我们报告了Sam35的鉴定，它是首个对细胞生存能力至关重要的外周线粒体外膜蛋白。Sam35（由酿酒酵母开放阅读框YHR083w编码）是SAM复合物的一个新亚基，对于外膜β-桶蛋白（如Tom40和孔蛋白的前体）的组装途径至关重要。内膜或基质靶向蛋白的导入不需要Sam35。SAM复合物中存在两种必需蛋白Sam35和Sam50，这表明它在线粒体生物发生中起核心作用。
