biostudies-literatureMelero AMedical Research Councilar122https://www.ebi.ac.uk/biostudies/studies/S-EPMC9634970biostudies-literatureUnknown33(13)Traffic of proteins out of the endoplasmic reticulum (ER) is driven by the COPII coat, a layered protein scaffold that mediates the capture of cargo proteins and the remodeling of the ER membrane into spherical vesicular carriers. Although the components of this machinery have been genetically defined, and the mechanisms of coat assembly extensively explored in vitro, understanding the physical mechanisms of membrane remodeling in cells remains a challenge. Here we use correlative light and electron microscopy (CLEM) to visualize the nanoscale ultrastructure of membrane remodeling at ER exit sites (ERES) in yeast cells. Using various COPII mutants, we have determined the broad contribution that each layer of the coat makes to membrane remodeling. Our data suggest that inner coat componentsMolecular biology of the cellUltrastructure of COPII vesicle formation in yeast characterized by correlative light and electron microscopy.PMC9634970MC_UP_1201/8MC_UP_1201/10Melero AKukulski WMiller EABoulanger JfalseUltrastructure of COPII vesicle formation in yeast characterized by correlative light and electron microscopy.Traffic of proteins out of the endoplasmic reticulum (ER) is driven by the COPII coat, a layered protein scaffold that mediates the capture of cargo proteins and the remodeling of the ER membrane into spherical vesicular carriers. Although the components of this machinery have been genetically defined, and the mechanisms of coat assembly extensively explored in vitro, understanding the physical mechanisms of membrane remodeling in cells remains a challenge. Here we use correlative light and electron microscopy (CLEM) to visualize the nanoscale ultrastructure of membrane remodeling at ER exit sites (ERES) in yeast cells. Using various COPII mutants, we have determined the broad contribution that each layer of the coat makes to membrane remodeling. Our data suggest that inner coat components2022-01-01T00:00:00Z2022 Nov2025-04-21T14:18:41.517Z2025-04-21T14:18:41.517ZS-EPMC96349703600136010.1091/mbc.E22-03-0103