Charakterisierung eines neuen Sortierungsweges für ein Protein der Plasmamembran

真核细胞主要利用分泌(SEC)途径进行质膜蛋白的生物发生。这种运输途径始于将膜蛋白插入内质网(ER)的膜中，然后是货物的囊泡运输到高尔基体，然后分选到最终目的地。最近的研究表明，一些分泌的和膜上的蛋白质是独立于SEC途径进行分类的。这些过程背后的分子机制尚不清楚。在酿酒酵母中，多聚体膜蛋白Ist2p是由位于子代细胞外围内质网附近的一种定位的mRNA编码的。我们已经证明，Ist2p到PM的传递不依赖于SEC介导的ER到高尔基体、高尔基体内和高尔基体到PM的运输，这表明Ist2p通过一条新的运输途径到达PM将它们定义为这条新的Ich denkepathway的货物的蛋白质的性质以及调节它们运输的因素尚不清楚。因此，我们的目标是鉴定Ist2p的分选信号，它是介导SEC非依赖性转运到PM的信号，我们将利用酵母遗传学来鉴定相关因素。

Eukaryotic cells mainly use the secretory (sec)-pathway for the biogenesis of plasma membrane (PM) proteins. This transport route begins with the insertion of membrane proteins into the membrane of the endoplasmic reticulum (ER), followed by the vesicular transport of cargo to the Golgi-apparatus and the sorting to the final destination. Recent studies have suggested that some secreted and membrane proteins are sorted independently of the sec-pathway. The molecular mechanisms underlying these processes are unknown. In the yeast Saccharomyces cerevisiae, the polytopic membrane protein Ist2p is encoded by a localized mRNA that has been found in proximity of the ER at the periphery of daughter cells. We have shown hat the delivery of Ist2p to the PM is independent of sec-mediated ER to Golgi-, intra-Golgi and Golgi to PM-transport suggesting that Ist2p travels on a novel trafficking pathway to the PM. The properties of proteins that define them as cargo for this novel Ich denkepathway and the factors that mediate their trafficking are unknown. Therefore we aim to characterize the sorting signals of Ist2p, which mediate the sec-independent transport to the PM, and we are going to identify the involved factors by employing yeast genetics.