Subcellular organization of the Tat translocation machinery

双精氨酸转位(TAT)机制可以将折叠的蛋白质跨生物膜转位。TAT系统的组成部分已经确定，其结构和功能是当前国际研究的主题。通过将绿色荧光蛋白(GFP)融合到大肠杆菌的TAT组分中，我们最近揭示了TatB和TatC这两个转位基因的基本成分，主要定位于细胞内(Berthelmann和Bruüser，2004)。相比之下，塔塔分布较少集中在两极。我们现在计划研究这种亚细胞组织的转位成分的结构基础和功能后果。将利用GFP融合技术和电子显微镜详细研究TAT系统组件的不同组合的定位。正如我们从初步结果中预计的那样，观察到的极性结构可能对理解TAT系统的功能有很大帮助。电子显微镜分析将在邻近生物中心的显微镜单元中进行。已知的极性决定因素的作用--如Min系统或肌动蛋白家族的细菌蛋白--将被讨论。分选因素将通过体内和体外蛋白质相互作用分析进行分析，并将在体内测试其功能。

The twin-arginine translocation (Tat) machinery can translocate folded proteins across biological membranes. Components of the Tat system have been identified and their structure and function are subject of current international research. By fusing the green fluorescent protein (GFP) to the Tat components from Escherichia coli, we recently revealed that TatB and TatC, two essential components of the translocon, are mainly polarly localized within the cells (Berthelmann and Brüser, 2004). In contrast, TatA distribution is less focussed at the poles. We now plan to study the structural basis and functional consequences for this subcellular organization of the translocon components. The localization of different combinations of Tat system components will be studied in detail by GFP-fusion techniques and electron microscopy. As we expect from preliminary results, observed polar structures might contribute significantly to the understanding of Tat system functionality. The electron micros-copical analyses will be carried out in the microscopy unit at the neighbouring Biocenter. The role of known polarity determining factors - such as the Min system or bacterial proteins of the actin-family - will be addressed. Sorting factors will be analyzed by in vivo and in vitro protein interaction analyses and their functionality will be tested in vivo.