Ribosome-associated vesicles: A dynamic subcompartment of the endoplasmic reticulum in secretory cells
Stephen D. Carter, Cheri M. Hampton, Robert Langlois, Roberto Melero, Zachary J. Farino, Michael Calderon, Wen Li, Callen T. Wallace, Ngoc-Han Tran, Robert A. Grassucci, Stephanie Siegmund, Joshua G. Pemberton, Travis J. Morgenstern, Leanna Eisenman, Jenny I. Aguilar, Nili L. Greenberg, Elana S. Levy, Edward Yi, William Mitchell, William J. Rice, Christoph Wigge, Jyotsna Pilli, Emily W. George, Despoina Aslanoglou, Maïté Courel, Robin Freyberg, Jonathan A. Javitch, Zachary P. Wills, Estela Área-Gómez, Sruti Shiva, Francesca Bartolini, Allen Volchuk, Sandra Murray, Meir Aridor, Kenneth N. Fish, Peter Walter, Tamás Balla, Deborah Fass, Sharon G. Wolf, Simon C. Watkins, J.M. Carazo, Grant J. Jensen, Joachim Frank, Zachary Freyberg
Abstract
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.