Figure 2. COPII is required to package PC1 into reconstituted vesicles.

Budding requirements of PC1 and HSP47 (a collagen-specific chaperone) were assessed under different incubation conditions described in Table 1. The top fraction after flotation was taken from each sample and analyzed by immunoblotting. Ribophorin I is an ER resident protein that serves as a negative control. ERGIC53 and SEC22B are found in conventional COPII vesicles and serve as positive controls. (Republished from Gorur et al., 2017 )