The endoplasmic reticulum (ER) is a highly dynamic network of membranes. Here, we combine live-cell microscopy with in situ cryo-electron tomography to directly visualize ER dynamics in several secretory cell types including pancreatic β-cells and neurons under near-native conditions. Using these imaging approaches, we identify a novel, mobile form of ER, ribosome-associated vesicles (RAVs), found primarily in the cell periphery, which is conserved across different cell types and species. We show that RAVs exist as distinct, highly dynamic structures separate from the intact ER reticular architecture that interact with mitochondria via direct intermembrane contacts. These findings describe a new ER subcompartment within cells.

中文翻译：

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核糖体相关囊泡：分泌细胞内质网的动态亚区室。


内质网（ER）是一个高度动态的膜网络。在这里，我们将活细胞显微镜与原位冷冻电子断层扫描相结合，直接可视化几种分泌细胞类型（包括接近天然条件下的胰腺β细胞和神经元）的内质网动态。利用这些成像方法，我们确定了一种新型的移动形式的内质网，即核糖体相关囊泡 (RAV)，它主要存在于细胞外周，在不同的细胞类型和物种中是保守的。我们表明，RAV 作为独特的、高度动态的结构存在，与完整的内质网网状结构分开，通过直接的膜间接触与线粒体相互作用。这些发现描述了细胞内一个新的内质网亚区室。