调节actin的WAVE复合体的结构和控制
Zhucheng Chen1, Dominika Borek, Shae B Padrick
1Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
Nature
|November 26, 2010
概括
波浪监管综合体 (WRC) 控制了行动动态. 它的结构揭示了Rac GTPase和激酶如何通过破坏抑制接触的稳定性来激活WRC,从而使lamellipodia形成.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 维斯科特-阿尔德里奇综合征蛋白 (WASP) 家族调节细胞骨动力学.
- 在波浪监管综合体 (WRC) 内的WASP相对波浪,控制了lamellipodia形成.
- WRC通常对Arp2/3复合体不活跃,但可以通过Rac GTPase,激酶和酸氨基醇刺激.
研究的目的:
- 为了确定WRC的晶体结构.
- 阐明由Rac GTPase,激酶和脂蛋白激活WRC的机制.
- 了解WRC如何通过Arp2/3复合体调节actin核化.
主要方法:
- 射线晶体学 (2.3安格斯特罗姆分辨率)
- 生物化学测定 生物化学测定
- 机械分析分析机械分析
主要成果:
- 晶体结构显示,WAVE的Verprolin同源性,Cofilins同源性和酸性 (VCA) 基因在WRC中被隔离.
- Rac GTPase和激酶破坏了负责VCA结合的关键WRC元素的稳定性,从而激活了该复合体.
- 在WRC的结构表明由Rac GTPase和脂合作招募到膜.
结论:
- 该WRC结构提供了关于WAVE蛋白对actin核化的调节的见解.
- Rac GTPase,激酶和脂化合物协同作用,控制WRC活动和局部化.
- 了解WRC调节对于理解细胞迁移和细胞骨动态至关重要.
相关概念视频
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...
Introduction to Actin
Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle cells, while in non-muscle cells, it is lower and makes up around 1–5 percent of the total cell protein. Actin found in the unicellular amoebae and complex multicellular animals is around 80% similar, demonstrating their conservation over a billion years of evolution. Actin coding genes are conserved within species and across different species.
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...
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...
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...
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...


