Protein integration into the mitochondrial outer membrane

大多数线粒体蛋白由核DNA编码，在细胞质中合成，并输入到各种线粒体亚室中。外膜蛋白含有不可切割的靶向和分选信号。目前，这些信号和蛋白质整合到线粒体外膜的机制尚不清楚。提出的研究的一个目标是研究跨越外膜一次的蛋白质的膜整合途径。为此，我们将结合基于位点特异性修饰的插入试验，使用从不同菌株分离的脂质囊泡和线粒体。下拉试验将用于鉴定这种蛋白质的假定插入酶。此外，ß-barrel蛋白的前体靶向线粒体并在细胞器内分类的分子机制将被研究。为了解决这个问题，我们将在这些蛋白中寻找靶向信号，并分析前体蛋白从TOM到TOB复合物的传递。此外，我们将使用遗传筛选来研究TOB机制的单个组件的功能。这些实验将为线粒体外膜蛋白的生物发生提供新的见解。

Most mitochondrial proteins are encoded by nuclear DNA, synthesized in the cytosol, and imported into the various mitochondrial sub-compartments. Proteins of the outer membrane contain non-cleavable targeting and sorting signals. Currently, these signals and the mechanism of protein integration into the mitochondrial outer membrane are unclear. One goal of the proposed study is to investigate the membrane integration pathway of proteins that span the outer membrane once. To that end, we will combine an insertion assay based on site-specific modification with the usage of lipid vesicles and mitochondria isolated from various strains. Pull-down assays will be used to identify a putative insertase for such proteins. Furthermore, the molecular mechanism by which precursors of ß-barrel proteins are targeted to mitochondria and sorted within the organelle will be studied. To address this questions we will search for targeting signals in these proteins and will analyze the relay of precursor proteins from the TOM to the TOB complex. Furthermore, we will use a genetic screen to study the function of single components of the TOB machinery. These experiments will provide new insights into the biogenesis of mitochondrial outer membrane proteins.