精製されたコートタンパク質と化学的に定義されたリポソームで再構成されたCOPIIコーティングの膀形成

K Matsuoka¹, L Orci, M Amherdt

¹Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley 94720, USA.

Cell

|May 6, 1998

まとめ

COPIIの水泡形成は,特定の脂質に結合するSar1p,Sec13/31p,Sec23/24pのタンパク質に依存しています. この連続的な組み立てが,ER膜からCOPIIで覆われた膀の芽を駆動する.

科学分野:

細胞生物学細胞生物学
メンブラン密輸膜密輸
タンパク質と脂質の相互作用

背景:

COPII (コート複合体II) 膀は,エンドプラズマ網膜 (ER) 輸出を媒介する.
膀の形成は,膜の採用と芽生えのためにコートタンパク質と特定の脂質を必要とします.

研究の目的:

膜上のCOPIIコートタンパク質の連続組立機構を解明する.
COPII 膀形成における特定の脂質の役割を調査する.

主な方法:

精製されたCOPIIコートタンパク質 (Sar1p,Sec23/24p,Sec13/31p) を使用したリポソーム結合アッセイ.
脂質とタンパク質の相互作用の研究では,PI-4-フォスファートとPI-4,5-ビスフォスファートを使用した.
電子顕微鏡を用いた芽生えイベントの超構造分析.

主要な成果:

Sar1p (GTP結合) はSec23/24pをリポソームとER膜に誘導する.
Sar1p-Sec23/24p複合体は,Sec13/31p結合に不可欠である.
リポソームのCOPIIコート組成は,膜の破裂なしにコーティングされたパッチ,芽,および膀 (50-90 nm) を導きます.

結論:

COPIIコートの組み立ては,特定の脂質にSar1p結合によって開始される段階的なプロセスです.
この脂質媒介のシーケンスアセンブリは,ERからCOPIIベシクルの形成と芽生えを促します.

さらに関連する動画

10:43

Preparation, Purification, and Use of Fatty Acid-containing Liposomes

Published on: February 9, 2018

108.1K

10:19

In Vitro Reconstitution of the Actin Cytoskeleton Inside Giant Unilamellar Vesicles

Published on: August 25, 2022

3.7K

関連する概念動画

00:59

COP Coated Vesicles

12.7K

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...

12.7K

01:32

Pinching-off of Coated Vesicles

3.2K

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...

3.2K

01:33

Coat Assembly and GTPases

3.5K

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...

3.5K

01:45

Vesicular Tubular Clusters

2.5K

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...

2.5K

01:12

Clathrin Coated Vesicles

8.2K

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...