Van1p-myc, Anp1-myc, and Mnn9p-myc are enriched in COPII vesicles
generated from microsomes of cycloheximide-treated cells. Vesicles
(right two lanes) were generated by incubation of microsomal membranes
with purified COPII components, and proteins were resolved on
SDS/PAGE. For quantitation, 30%, 20%, 10%, 5%, and 1% fractions
from the total membrane content were compared with vesicle proteins by
immunoblot (left five lanes).