Boulder Laboratory for Three-Dimensional Electron Microscopy of Cells, University of Colorado at Boulder, Boulder, CO 80309, USA.
J Cell Biol. 2010 Aug 9;190(3):363-75. doi: 10.1083/jcb.200911024.
The endoplasmic reticulum (ER) network is extremely dynamic in animal cells, yet little is known about the mechanism and function of its movements. The most common ER dynamic, termed ER sliding, involves ER tubule extension along stable microtubules (MTs). In this study, we show that ER sliding occurs on nocodazole-resistant MTs that are posttranslationally modified by acetylation. We demonstrate that high MT curvature is a good indicator of MT acetylation and show in live cells that ER sliding occurs predominantly on these curved, acetylated MTs. Furthermore, increasing MT acetylation by drug treatment increases the frequency of ER sliding. One purpose of the ER sliding on modified MT tracts could be to regulate its interorganelle contacts. We find that all mitochondria and many endosomes maintain contact with the ER despite the movements of each. However, mitochondria, but not endosomes, preferentially localize to acetylated MTs. Thus, different ER dynamics may occur on distinct MT populations to establish or maintain contacts with different organelles.
内质网（ER）网络在动物细胞中极其动态，但对其运动的机制和功能知之甚少。最常见的 ER 动态，称为 ER 滑行，涉及 ER 小管沿着稳定的微管（MT）延伸。在这项研究中，我们表明 ER 滑行发生在翻译后乙酰化修饰的紫杉醇抗性 MT 上。我们证明了高 MT 曲率是 MT 乙酰化的良好指标，并在活细胞中表明 ER 滑行主要发生在这些弯曲的、乙酰化的 MT 上。此外，通过药物处理增加 MT 乙酰化会增加 ER 滑行的频率。修饰后的 MT 道上的 ER 滑行的一个目的可能是调节其细胞器间的接触。我们发现，尽管每个细胞器都在运动，但所有的线粒体和许多内体都与 ER 保持接触。然而，线粒体而不是内体，优先定位于乙酰化的 MT 上。因此，不同的 ER 动力学可能发生在不同的 MT 群体上，以与不同的细胞器建立或维持接触。
