Budding of COPII-coated vesicles is not affected by LMAN1 deficiency. Semi-intact WT and Lman1^−/− MEFs were permeabilized with digitonin and served as sources of the ER membranes. COPII proteins were supplied in rat liver cytosol. COPII-coated vesicles bud from the ER membrane with the addition of guanosine triphosphate and the adenosine triphosphate regeneration mix. The vesicles were purified by differential centrifugation and analyzed by Western blotting using the indicated antibodies.