Mechanisms of Golgi Apparatus Protein Recycling

描述：我们的长期目标是对高尔基体有一个完整的分子定义 器官生物发生学。高尔基体是中央细胞器。 人类细胞的分泌途径。细胞是如何产生明显稳定的 分泌途径中的下游细胞器，特别是高尔基体 装置，同时确保新的 人工合成的蛋白质到质膜，是细胞中的一大挑战 生物学。我们发现所谓的驻留高尔基体膜蛋白循环 以不依赖于高尔基体的外壳蛋白的方式连续地 急诊室。在缺乏任何基因的情况下，这种循环发生在野生型细胞中 具有直接的医学意义，因为它是 大量细菌和植物蛋白毒素的最终投放 细胞中毒的地方。 这项拟议研究的直接目标是确定分子的特征 产生这种不依赖外壳蛋白的高尔基体至内质网蛋白的机制 循环使用路径。我们知道rab6和rab33b是该途径的调节者， 并假设Rab效应器很重要。建议的具体目标是： 1.中间体的表征。初步实验表明， 晚期作用、膜转运机制蛋白的表达阻断高尔基体 糖基转移酶回收到ER。将使用这种方法和其他方法 来描述中间体的特征。 2.确定Rab33b和rab6在 路径。Rab6比Rab33b具有更强的反式定位能力。两个RAB在一起吗？ 平行的还是串联的？ 3.Rab效应器和In的功能重要性表征 高尔基体到内质网循环中的特定Rab33b效应器。Rab33b和Rab6的体外实验 显示不同的效应器模式，但每个效应器似乎都调节高尔基体 糖基转移酶循环至内质网。这是如何在分子意义上发挥作用的？ 我们建议使用rab33b和rab6及其效应器作为主要分子。 解剖居留性高尔基体蛋白循环利用的机制和途径 急诊室。总而言之，我们建议在我们的 关于高尔基体生物发生的认识。

DESCRIPTION: Our long-term goal is a complete molecular definition of Golgi apparatus biogenesis. The Golgi apparatus is the central organelle within the secretory pathway of human cells. How the cell generates apparently stable downstream organelles within the secretory pathway, specifically, the Golgi apparatus, while at the same time ensuring vectorial transport of newly synthesized protein to the plasma membrane, is a major challenge in cell biology. We find so-called resident Golgi apparatus membrane proteins recycle continuously in a coat protein independent manner from the Golgi apparatus to the ER. This recycling occurs in wild type cells in the absence of any genetic manipulation and is of immediate medical significance as it is a key step in the delivery of numerous bacterial and plant protein toxins to their ultimate site of cellular intoxication. The immediate aims of the proposed research are to characterize the molecular mechanisms that produce this novel coat-protein-independent Golgi-to-ER protein recycling pathway. We know that rab6 and rab33b are regulators of the pathway, and assume that rab effectors are important. The proposed Specific Aims are: 1. Characterization of intermediates. Preliminary experiments suggest that expression of late acting, membrane trafficking machinery proteins block Golgi glycosyltransferase recycling to the ER. This and other approaches will be used to characterize intermediates. 2. Determination if rab33b and rab6 act in parallel or in series within a pathway. Rab6 is more trans in localization than rab33b. Do the two rabs act in parallel or in series? 3. Characterization of the functional importance of rab effectors and in particular rab33b effectors in Golgi to ER recycling. Rab33b and rab6 in vitro display a different pattern of effectors yet each seems to regulate Golgi glycosyltransferase cycling to the ER. How does this work in a molecular sense? We propose to use rab33b and rab6 and their effectors as the prime molecular handles to dissect mechanism and pathway of resident Golgi protein recycling to the ER. In conclusion, we propose a mechanistic step forward in our understanding of Golgi apparatus biogenesis.