人間のArp2/3複合体とListeria monocytogenes ActAタンパク質がアクチン線維核化における相互作用
関連する実験動画
Updated: Aug 3, 2026

08:57
Aip1p Dynamics Are Altered by the R256H Mutation in Actin
Published on: July 30, 2014
M D Welch1, J Rosenblatt, J Skoble
1Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143, USA.
まとめ
病原性細菌Listeria monocytogenesは,そのActAタンパク質を使用して,宿主細胞のアクチン関連タンパク質2/3 (Arp2/3) コンプレクスを活性化させ,アクチンフィラメントアセンブリを侵入に駆動します.
科学分野:
- 微生物学 微生物学とは
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
背景:
- Listeria monocytogenesのような病原性細菌は,侵入のために宿主細胞のプロセスを操作します.
- アクチン線維の組み立ては,細胞構造,運動性,病原体の侵入に不可欠です.
研究 の 目的:
- Listeria monocytogenes ActAタンパク質が宿主Arp2/3複合体と相互作用するメカニズムを調査する.
- バクテリアの表面でのアクチンポリメリゼーションの開始におけるActAの役割を明らかにする.
主な方法:
- アクチン核化を研究するために,インビトロ生化学分析を用いた.
- 純化されたArp2/3複合体とActAタンパク質の単体および組み合わせによるアクチンポリメリゼーションへの効果を測定した.
主要な成果:
- 純粋化されたArp2/3複合体だけで,アクチン核形成の加速が最小限であることが示された.
- 純粋化されたActAタンパク質だけでは,アクチン核形成に効果がなかった.
- 結合されたArp2/3複合体とActAは,アクチン線維の核化をシネジスティックに刺激した.
結論:
- Listeria monocytogenes ActAタンパク質は,主体Arp2/3複合体を直接活性化し,アクチンポリメリゼーションを促進する.
- この細菌の戦略は,アクチンダイナミクスを調節する宿主細胞のメカニズムを模倣し,細菌の侵入を容易にします.
関連する概念動画
Actin Polymerization
Actin polymerization occurs through the head-to-tail association of binding sites on monomeric actin or G-actin to form filamentous or F-actin. The polymerization can be divided into three phases ̶ nucleation, elongation, and steady-state phase.
The nucleation phase involves forming a stable nucleus consisting of three actin monomers to form a new actin filament. Actin-binding proteins such as formins and Arp2/3 complex help filament growth post-nucleation. The Formins form straight actin...
The nucleation phase involves forming a stable nucleus consisting of three actin monomers to form a new actin filament. Actin-binding proteins such as formins and Arp2/3 complex help filament growth post-nucleation. The Formins form straight actin...
Generation of Straight or Branched Actin Filaments
The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Actin Filament Depolymerization
Actin filaments (F-actin) are composed of actin subunits. The dissociation of actin monomers can occur from either end of F-actin. The rate of dissociation is faster from the minus-end or the pointed end, where the actin subunits exist with a bound ADP, together known as ADP-actin. The depolymerization of F-actin is aided by proteins, including the actin-depolymerizing factor (ADF) and cofilin family of proteins, gelsolin, and glia maturation factor (GMF).
In F-actin, the ADF/cofilin proteins...
In F-actin, the ADF/cofilin proteins...
Formation of Higher-order Actin Filaments
The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin networks...
The high-order actin networks...
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...
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...
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...

