This research paper investigates the assembly of the coat protein complex II (COPII) on cargo-containing membranes using cryo-electron tomography. The study reconstituted COPII-coated membrane carriers using purified *Saccharomyces cerevisiae* proteins and cell-derived microsomes. Cryo-electron tomography with subtomogram averaging revealed that COPII forms largely spherical vesicles from native membranes, detailing the architecture of the inner and outer coat layers and shedding light on spherical carrier formation. The results provide insights into COPII coat architecture and regulation, advancing the understanding of membrane curvature generation.

Euan Pyle, Elizabeth A. Miller, Giulia Zanetti