Ungar Daniel, Oka Toshihiko, Vasile Eliza, Krieger Monty, Hughson Frederick M
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
J Biol Chem. 2005 Sep 23;280(38):32729-35. doi: 10.1074/jbc.M504590200. Epub 2005 Jul 14.
The conserved oligomeric Golgi (COG) complex is thought to function in intra-Golgi retrograde trafficking mediated by coat protein I vesicles, a pathway essential for the proper structure and function of the Golgi apparatus. Previous work suggested that COG might act as a tethering factor to mediate the initial attachment between coat protein I vesicles and Golgi membranes. Here, we present extensive in vitro co-translation and immunoprecipitation experiments leading to a new model for the overall architecture of the mammalian COG complex. The eight COG subunits (Cog1-8) are found to form two heterotrimeric subassemblies (Cog2/3/4 and Cog5/6/7) linked by a heterodimer composed of the remaining subunits (Cog1/8). This model is in excellent agreement with in vivo data presented in an accompanying paper (Oka, T., Vasile, E., Penman, M., Novina, C. D., Dykxhoorn, D. M., Ungar, D., Hughson, F. M., and Krieger, M. (2005) J. Biol. Chem. 280, 32736-32745).
保守寡聚高尔基体（COG）复合体被认为在由衣被蛋白I小泡介导的高尔基体内逆行运输中发挥作用，这是一条对高尔基体正确结构和功能至关重要的途径。先前的研究表明，COG可能作为一种拴系因子，介导衣被蛋白I小泡与高尔基膜之间的初始附着。在此，我们展示了广泛的体外共翻译和免疫沉淀实验，得出了一个关于哺乳动物COG复合体整体结构的新模型。发现八个COG亚基（Cog1 - 8）形成两个异源三聚体亚组件（Cog2/3/4和Cog5/6/7），它们由其余亚基（Cog1/8）组成的异源二聚体连接。该模型与随附论文（Oka, T., Vasile, E., Penman, M., Novina, C. D., Dykxhoorn, D. M., Ungar, D., Hughson, F. M., and Krieger, M. (2005) J. Biol. Chem. 280, 32736 - 32745）中呈现的体内数据高度吻合。
