アクチンダイナミクスは,クラトリン独立性エンドサイトーシスにおける膜の再編成と分裂を駆動する

Winfried Römer¹, Léa-Laetitia Pontani, Benoît Sorre

¹Institut Curie, Centre de Recherche, CNRS UMR, Paris, France. winfried.roemer@curie.fr

Cell

|February 25, 2010

まとめ

アクチンの再編成は,Shiga毒素誘発の膜管の分裂を促し,コレステロールに依存するプロセスですが,ダイナミンの独立です. これは,エンドサイトーシス中の膜収縮の物理的メカニズムを示唆しています.

科学分野:

細胞生物学細胞生物学
メンブラン密輸膜密輸
バイオフィジックス生物物理学

背景:

膜分裂は,エンドサイトーシス中の膀形成に不可欠です.
ダイナミン依存型と独立した分裂機構が存在し,後者はほとんど理解されていません.
クラトリン独立性エンドサイトーシスは,ダイナミン独立性分裂を含みます.

研究の目的:

シガ毒素誘発性内分細胞症におけるダイナミン独立性膜分裂のメカニズムを解明する.
この分裂過程におけるコレステロールとアクチンの役割を調査する.
膜管の収縮を誘発する物理的力を探求する.

主な方法:

アクチン成分 (Arp2) の細胞の枯渇.
コレステロールに依存する膜再編成の研究.
リポソームベースのモデル膜実験.
シガ毒素誘発性エンドサイトーシスアッセイ.

主要な成果:

コレステロールに依存する膜の再編成は,シガ毒素管の分裂に先行する.
アクチンは,膜の再編成を誘導することによって分裂を誘発します.
リポソームのアクチン殻形成は,コレステロールに依存し,ダイナミンに依存しないチューブル分裂を誘導する.
Arp2の枯渇に伴い,管状の発生が増加する.

結論:

ドメイン境界力によって誘発されるアクチン誘発の膜再編成は,シガ毒素チューブルの分裂を媒介する.
この物理的メカニズムは,ピンチャージ活動と独立してまたは連携して動作します.
コレステロールは,アクチン媒介分裂の調節に重要な役割を果たします.

さらに関連する動画

12:40

Visualizing Clathrin-mediated Endocytosis of G Protein-coupled Receptors at Single-event Resolution via TIRF Microscopy

Published on: October 20, 2014

12:15

In Vitro Polymerization of F-actin on Early Endosomes

Published on: August 28, 2017

関連する概念動画

01:32

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...

01:13

Actin Polymerization and Cell Motility

Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.

01:39

Mechanism of Filopodia Formation

Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...

01:31

Mechanism of Lamellipodia Formation

Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...

01:16

Cell Motility through Blebbing

Blebs are a type of membrane protrusion formed by the internal hydrostatic pressure of the cytoplasm. Blebs are observed in several cell types, including fibroblasts, immune cells, and single-celled organisms like the amoeba. The primary function of blebs is cell locomotion and apoptosis, but they are also found during necrosis and cell division. The life cycle of a bleb comprises an initiation phase followed by the expansion and retraction phases.
Blebbing Through the Matrix
In multicellular...

01:12

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...

関連する実験動画