联结启动单分子整合素的构成激活
Jing Li1, Myung Hyun Jo2, Jiabin Yan3
1Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
整合素的激活始于在连接器结合时的外向信号,然后是内向信号. 通过actin细胞骨架的拉力传递对于完全的整合激活至关重要.
科学领域:
- 细胞生物学
- 生物物理
- 分子动力学
背景情况:
- 整合素是关键的细胞表面受体,通过将细胞外基质连接到actin细胞骨架来调解细胞粘附和迁移.
- 细胞外环境与细胞内部之间的快速沟通对于细胞过程至关重要.
- 了解整合素在配体结合和细胞骨相互作用时的构造变化是解读细胞信号的关键.
研究的目的:
- 研究整合素在配体结合和塔林相互作用时的动态构造变化.
- 阐明由外向和内向信号启动的整合素激活的序列和机制.
- 确定塔林和细胞骨紧张在整合素激活中的作用.
主要方法:
- 用单分子光动力学实时观察整合素的构造状态.
- 分析的重点是对联体结合事件和随后的结构重组.
- 评估了塔林结合对整合素构成的影响.
主要成果:
- 与占主导地位的曲封闭整合素结合会触发快速 (毫秒时间尺度) 的腿部延伸和头部开放,形成高亲和度状态.
- 可以从扩展开放状态直接访问扩展闭合形态,从而促进连接体解离.
- 单独的塔林结合会适度地稳定整合素,但不会诱导激活所需的形状延伸或开放.
- 整合素激活涉及一个由外向信号发出,随后由内向信号发出的顺序过程.
结论:
- 整合素激活是一个多步骤的过程,由细胞外线引发,并由细胞内元件调节.
- 塔林结合是必要的,但不足以进行内外整合激活;通过actin细胞骨架传递拉力是必不可少的.
- 这些发现为整合素的形状变化和激活机制提供了一个动态模型,强调了外部力量和细胞内信号通路之间的相互作用.
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