在稳定状态下,依赖ATP的actin尖端波动在稳定状态下
Madhura Duttagupta1, Andrew T Riley1, William M Brieher1
1Department of Cell and Developmental Biology, University of Illinois Urbana Champaign, Urbana, IL 61801.
概括
试验室内阿克丝的动态表现出频繁的,小的尖端波动和更罕见的大波动,影响长度扩散性. 这些取决于ATP水解的波动,为actin网络周转提供了新的见解.
科学领域:
- 生物化学 生物化学
- 细胞生物学 细胞生物学
- 生物物理学的生物物理.
背景情况:
- 动氨酸网络对于细胞过程至关重要,并且表现出不断的周转.
- 行为动力学的主要模型是跑步机,预测稳定的线程长度.
- 之前的研究报告了不清楚起源的丝丝长度波动 (扩散性) 超过预期.
研究的目的:
- 在实验室中研究纯乙烯纤维中的高长度扩散的起源.
- 为了表征青丝纤维中尖端波动的性质和动力学.
主要方法:
- 通过α-actinin. 通过玻璃连接的单个actin丝成像.
- 实时观察和量化尖端波动.
- 分析波动对ATP水解,无机酸盐释放和封装剂的依赖.
主要成果:
- 观察到频繁的,低幅度 (±2-6个子单位) 和罕见的,高幅度 (±50-150个子单位) 的尖端波动.
- 证明了波动取决于ATP水解和Pi释放,并被phalloidin和封闭剂抑制.
- 据估计,在稳定状态下,波动消耗了三分之一的ATP,导致长度扩散度超过纯跑步机预测,但低于之前报告的.
结论:
- 动氨酸丝的动态表现出一种缓和的动态不稳定性,其特征是叠加的小和大尖端波动.
- 这些波动解释了观察到的长度扩散性,这表明之前的测量包括了其他可变性来源.
- 这些发现为动因动态的动力学模型提供了直接的实验支持.
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