单分子斑点分析在lamellipodia中的actin丝周转率
Naoki Watanabe1, Timothy J Mitchison
1Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA. naoki_watanabe@hms.harvard.edu
Science (New York, N.Y.)
|February 9, 2002
概括
研究人员追踪了细胞lamellipodia中的单个actin分子,以了解actin聚合. 动氨酸丝的形成主要发生在拉美利波底尖之外,在整个细胞边缘的动力学是恒定的.
科学领域:
- 细胞生物学 细胞生物学
- 生物物理学的生物物理.
- 分子生物学分子生物学
背景情况:
- 拉美利波迪亚是关键的细胞结构,参与迁移和粘附.
- 在lamellipodia中的动因动态对于它们的功能至关重要,但在体内研究是复杂的.
- 了解actin聚合的空间调节是细胞运动性研究的关键.
研究的目的:
- 分析细胞lamellipodia内部的actin聚合和脱聚合的空间调节.
- 在体内以高空间精度测量动力学和活性丝的寿命.
- 为了阐明在lamellipodia中活性丝生成的主要位置.
主要方法:
- 在体内开发了一种方法来追踪与绿色光蛋白 (GFP) 融合的单个活性蛋白分子.
- 使用高分辨率显微镜监测actin聚合和脱聚合动态.
- 在lamellipodia内的不同位置的量化聚合率和actin线程寿命.
主要成果:
- 观测到基底性actin聚合和脱聚合,在lamellipodia中具有一致的动力学.
- 在拉梅利波底尖的1微米范围内确定了增强的活性聚合物.
- 确定了lamellipodia中的大多数活性丝源于远离尖端发生的聚合.
结论:
- 拉梅利波迪亚的动素丝组合在空间上受到调节,其中很大一部分发生在远离前沿的地方.
- 雅丁聚合和脱聚合的动力学在整个拉梅利波底体中基本上是均的.
- 这项研究为细胞形状和运动所必不可少的actin动态的空间控制提供了新的见解.
相关概念视频
01:14Generation 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...
01:19Actin 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...
01:13Actin 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.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
01:39Mechanism 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...
01:31Mechanism 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...
01:18Actin Treadmilling
Actin filaments undergo polymerization and depolymerization from either end. The polymerization and depolymerization rates depend on the cytosolic concentration of free G-actins. The polymerization rate is generally higher at the plus or barbed end, while the depolymerization rate is higher at the minus or pointed end. At a steady state, critical concentration describes the concentration of free G-actin monomers at which the polymerization rate at the plus end is equal to that of the...