PROTEIN TRANSPORT INTO MAMMALIAN ENDOPLASMIC RETICULUM

该项目的长期目标是了解蛋白质跨哺乳动物内质网(ER)膜运输或插入的分子机制。我们已经建立了重组蛋白脂质体和含有纯化的膜蛋白组分的可溶性系统，再现了整个转位过程和部分反应。内质网最小转位装置仅由异源三聚体Sec61p复合体、TRAM蛋白和SRP受体组成。我们现在建议对易位的机制进行彻底的分析。具体来说，我们将使用以下问题：1.共翻译易位是如何启动的？2.核糖体如何与Sec61p通道相互作用？3.膜蛋白是如何插入到脂质双层中的？4.哺乳动物中Sec62p和Sec63p的同系物有什么功能？这些研究将有助于我们理解大量蛋白质生物合成的第一步，也是决定性的一步，包括质膜蛋白质、溶酶体和分泌途径的所有细胞器。

The long-term goal of this project is to understand the molecular mechanism by which proteins are transported across or are inserted into the mammalian endoplasmic reticulum (ER) membrane. We have established reconstituted proteoliposome and soluble systems with purified membrane protein components which reproduce the overall translocation process and partial reactions. The minimum translocation apparatus of the ER membrane comprises only the heterotrimeric Sec61p complex, the TRAM protein, and the SRP receptor. We now propose to perform a thorough analysis of the mechanism of translocation. Specifically, we will use questions: 1. How is cotranslational translocation initiated? 2. How do ribosomes interact with the Sec61p channel? 3. How are membrane proteins inserted into the lipid bilayer? 4. What is the function of the mammalian homologs of Sec62p and Sec63p? These studies will contribute significantly to our understanding of the first and decisive step in the biosynthesis of a large of class proteins, proteins of the plasma membrane, of lysosomes, and of all organelles of the secretory pathway.