连接外套组件和囊泡芽到假设货物接收器的包装
M Bremser1, W Nickel, M Schweikert
1Biochemie-Zentrum Heidelberg, University of Heidelberg, Germany.
Cell
|March 3, 1999
概括
通过协同体介导的COPI涂层囊泡芽需要特定的蛋白质和GTP. 这一对于戈尔吉运输至关重要的过程,通过双价性体相互作用将货物吸收与囊泡形成联系起来.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 膜贩卖 膜贩卖 膜贩卖
背景情况:
- 用COPI涂层的囊泡在戈尔吉装置内调解逆行运输.
- 作为一个细胞质蛋白质复合体的辅酶体,对于COPI囊泡的形成至关重要.
- 正在研究在戈尔吉膜上启动COPI层组装的精确分子机制.
研究的目的:
- 阐明COPI涂层囊泡从戈尔吉类脂质双层中芽的分子要求.
- 调查货物受体和ARF-GTP在coatomer招募和囊泡形成中的作用.
- 建立基于脂质体的系统,用于在体外研究COPI囊泡芽.
主要方法:
- 使用模仿戈尔吉膜组成的蛋白质体复制COPI涂层囊泡芽.
- 在芽试验中包括纯化体,ARF和GTP.
- 囊泡特征 (直径,密度,形态) 和芽效率的分析.
主要成果:
- 覆盖COPI的囊泡芽取决于coatomer,ARF-GTP和特定的载荷/受体细胞质尾巴 (p24蛋白,KKXX信号).
- 脂质体衍生COPI囊泡具有与原生囊泡相似的特性,包括尺寸,密度和温度依赖性.
- 一个双价相互作用模型解释了coatomer组合,将货物结合与囊泡形成联系起来.
结论:
- 涂层体与膜结合的ARF-GTP和货物尾巴的双价相互作用驱动了COPI涂层组装.
- 这种机制提供了货物识别和运输囊泡的形成之间的直接联系.
- 该研究提供了一个简化的模型来理解戈尔吉逆行运输启动.
相关概念视频
COP Coated Vesicles
Membrane-enclosed structures called vesicles transport proteins and lipids across the cell. The vesicles derive their cargo from the plasma membrane, Golgi, ER, or endosome. Coated vesicles are spherical, protein-coated carriers with a 50–100 nm diameter that mediate bidirectional transport between the ER and the Golgi. The distribution of proteins between the ER and Golgi complex is dynamic and is maintained by different coated vesicles. Their formation is driven by the assembly of different...
Pinching-off of Coated Vesicles
Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...
Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Vesicular Tubular Clusters
After budding out from the ER membrane, some COPII vesicles lose their coat and fuse with one another to form larger vesicles and interconnected tubules called vesicular tubular clusters or VTCs. These clusters constitute a compartment at the ER-Golgi interface known as ERGIC (Endoplasmic Reticulum Golgi Intermediate Compartment). The ERGIC is a mobile membrane-bound cargo transport system that sorts proteins secreted from ER and delivers them to the Golgi.
With the help of motor proteins such...
With the help of motor proteins such...
Transport Across the Golgi
While it is unclear how molecules move between adjacent Golgi cisternae, it is apparent that the molecules move from cis- cisterna, the entry face, to the trans- cisterna, the exit face. Experiments initially suggested vesicles that bud from one cisterna and fuse with the next cisterna to transport proteins between the cisternae. This vesicular transport model describes the Golgi apparatus as a relatively static structure with a unique enzyme composition in each cisterna. Molecules are...
Clathrin Coated Vesicles
Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...


