Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
Sci Adv. 2020 Apr 1;6(14):eaay9572. doi: 10.1126/sciadv.aay9572. eCollection 2020 Apr.
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.
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，直接在接近自然状态下观察几种分泌细胞类型（包括胰腺β细胞和神经元）中的 ER 动态。使用这些成像方法，我们在不同的细胞类型和物种中发现了一种新型的、可移动的内质网形式，核糖体相关囊泡（RAV），它主要存在于细胞边缘。我们表明，RAV 作为与完整的 ER 网状结构分离的独特的、高度动态的结构存在，它们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的一个新的 ER 亚区室。
