Arf GTP-binding proteins and membrane traffic

Arf - gtp结合蛋白调节膜运输，转运中间体的形成和细胞器的结构。Arf1已被广泛研究，它定位于高尔基复合体并调节内质网和高尔基复合体之间的膜交通。Arf6存在于质膜和核内体上，并在调节核内体膜交通中起作用。该实验室的一个兴趣是鉴定Arf1和Arf6中指定定位和功能的序列。为了绘制Arf1中指定高尔基定位的序列，我们制作了Arf1和Arf6的嵌合体，并在细胞中表达这些嵌合的Arfs，以观察它们是否与高尔基复合体相关。我们在Arf1中发现了一个16个氨基酸的序列，当插入到Arf6中时，它可以与高尔基体结合。我们发现Arf1中的这些序列允许Arf1- gdp通过结合膜蛋白（一种与膜融合有关的高尔基相关蛋白）被招募到高尔基体的早期部分（Honda et al., 2005）。缺乏这些序列的Arf1只能与晚期高尔基体有关。这些研究揭示了Arf1与高尔基体复合体的不同和独特的相互作用，反映了高尔基体早期和晚期的不同调控分子。

Arf GTP-binding proteins regulate membrane traffic, the formation of transport intermediates and the structure of organelles. Arf1 has been extensively studied, localizes to the Golgi complex and regulates membrane traffic between the endoplasmic reticulum and the Golgi complex. Arf6 is present at the plasma membrane and on endosomes and functions in the regulation of endosomal membrane traffic. One interest of the lab has been in the identification of sequences in Arf1 and Arf6 that specify localization and function. In order to map out sequences in Arf1 that specify Golgi localization, we made chimeras of Arf1 and Arf6 and expressed these chimeric Arfs in cells to see whether they could associate with the Golgi complex. We identified a sixteen amino acid sequence in Arf1 that when inserted into Arf6 allowed it to associate with the Golgi. We found that those sequences in Arf1 allows Arf1-GDP to be recruited to the early part of the Golgi by binding to membrin, a Golgi-associated protein implicated in membrane fusion (Honda et al., 2005). Arf1 lacking those sequences could only associate with the late Golgi. These studies revealed the varied and distinct interactions that Arf1 has with the Golgi complex, reflecting different regulatory molecules on the early and late aspects of the Golgi.