用formins延长行为丝的分子机制
Wout Oosterheert1, Micaela Boiero Sanders1, Johanna Funk2
1Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany.
概括
甲指导着细胞的形状和运动. 一个新的"解锁"机制揭示了虫如何随着不断增长的状纤维移动, 控制延长速度.
科学领域:
- 细胞生物学
- 生物化学
- 结构生物学
背景情况:
- 甲是活性丝 (F-actin) 组合的关键调节剂,对于真核细胞的形态和运动是必不可少的.
- 甲和F-actin之间的精确分子相互作用及其作用机制仍然不完全理解.
研究的目的:
- 阐明甲-乙相互作用的结构基础和甲介导的乙丝延长的机制.
- 描述F-actin尖端的formins的结构动态及其在聚合过程中的转位.
主要方法:
- 使用高分辨率的冷电子显微镜 (cryo-EM) 来确定由不同形式结合的F-actin尖端的结构.
- 进行了actin-formin-profilin复合物的结构分析.
主要成果:
- 低温-EM结构显示出与F-actin刺结合的常见不对称形状,由丝结构决定.
- 一种新的"解锁"机制解释了胺转移如何通过硬质位移与氨酸聚合结合.
- 动氨酸-氨酸接口的稳定性和定位与快速和慢速氨酸之间观察到的丝长速度差异相关.
- 在丝延长过程中,actin-formin-profilin复合物的结构解释了profilin的快速释放.
结论:
- "解锁和锁定"机制提供了一个统一的解释,解释了形的过程性和与形丝成长的协调性.
- 胺转移和丝延长率由特定的胺-胺接口相互作用微调.
- 对动氨酸 - 氨酸 - 氨酸复合物的结构洞察揭示了氨酸释放的机制,这对于有效的动氨酸聚合是必不可少的.
相关概念视频
Generation of Straight or Branched Actin Filaments
2.9K
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...
2.9K
Actin Polymerization
6.6K
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...
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...
6.6K
Actin Filament Depolymerization
3.1K
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...
3.1K
Formation of Higher-order Actin Filaments
3.0K
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...
The high-order actin...
3.0K
Mechanism of Filopodia Formation
2.3K
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...
2.3K
Introduction to Actin
5.1K
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...
5.1K


