The structure of the COPI coat determined within the cell

• Published in: eLife Vol. 6
• Main Authors: Bykov, Yury S, Schaffer, Miroslava, Dodonova, Svetlana O, Albert, Sahradha, Plitzko, Jürgen M, Baumeister, Wolfgang, Engel, Benjamin D, Briggs, John Ag
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 17-11-2017; eLife Sciences Publications, Ltd
• Subjects: Algae; Cell Biology; Chlamydomonas reinhardtii; Chlamydomonas reinhardtii - chemistry; Coat Protein Complex I - chemistry; Coated vesicles; COP-Coated Vesicles - chemistry; COPI; cryo-electron tomography; Cryoelectron Microscopy; Electron Microscope Tomography; Endoplasmic reticulum; Golgi apparatus; Laboratories; Medical imaging; Membrane proteins; membrane trafficking; Membrane vesicles; Microscopy; Models, Molecular; Molecular biology; Morphology; Protein Conformation; Research Advance; Structural Biology and Molecular Biophysics; subtomogram averaging; Tomography; cell biology; Chlamydomonas reinhardtii; subtomogram averaging; COPI; structural biology; cryo-electron tomography; biophysics; membrane trafficking
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.32493

COPI-coated vesicles mediate trafficking within the Golgi apparatus and from the Golgi to the endoplasmic reticulum. The structures of membrane protein coats, including COPI, have been extensively studied with
reconstitution systems using purified components. Previously we have determined a complete structural model of the
reconstituted COPI coat (Dodonova et al., 2017). Here, we applied cryo-focused ion beam milling, cryo-electron tomography and subtomogram averaging to determine the native structure of the COPI coat within vitrified
cells. The native algal structure resembles the
mammalian structure, but additionally reveals cargo bound beneath β'-COP. We find that all coat components disassemble simultaneously and relatively rapidly after budding. Structural analysis
, maintaining Golgi topology, shows that vesicles change their size, membrane thickness, and cargo content as they progress from
to
, but the structure of the coat machinery remains constant.