Arp2/3複合体の結晶構造について
R C Robinson1, K Turbedsky, D A Kaiser
1Structural Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
まとめ
牛のArp2/3複合体の構造を決定し,真核細胞におけるアクチンポリメリゼーションに決定的な役割を果たしました. これは,主要なタンパク質の相互作用を明らかにし,WASp/Scarタンパク質がフィラメントの分岐のためにArp2/3複合体を活性化する方法を予測します.
科学分野:
- 細胞生物学 細胞生物学
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- Arp2/3複合体は,真核細胞におけるアクチン線維の核形成と分岐の開始に不可欠である.
- その構造を理解することは,アクチンダイナミクスと細胞運動性のメカニズムを解読する鍵です.
研究 の 目的:
- 牛のArp2/3複合体の高解像度結晶構造を決定する.
- Arp2/3 複合体の組立と機能の構造的基礎を解明する.
主な方法:
- 結晶構造を決定するために,X線結晶学を用いた.
- 構造は2.0アングストームの解像度で解像しました.
主要な成果:
- 7つのタンパク質からなる牛のArp2/3複合体の結晶構造は2.0アングストームの解像度で決定されました.
- アクチン関連タンパク質2 (Arp2) とArp3は,ユニークな表面特性を有するアクチンのような折りたたみを共有しています.
- 特定のサブユニット相互作用が特定され,コアにおけるアルファヘリル結合とARPC1のベータプロペラドメインを含む,アクチン繊維と相互作用する可能性がある.
結論:
- 構造データは,Arp2/3複合体のアーキテクチャとサブユニットの組織についての洞察を提供します.
- WASp/Scarタンパク質がArp2/3複合体の活性化を促進し,Arp2とArp3を枝分かれしたアクチンフィラメントの核化のために位置づけることで,モデルが提案されています.
関連する概念動画
Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
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...
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...
ATP Synthase: Structure
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...


