(A) COPII proteins fully coat nascent buds emerging from the ER, ultimately facilitating the generation of cargo-loaded vesicles for initiating the intracellular transport. (B) COPII proteins employ the condensation mechanism, in a manner regulated by Mn2+, to catalyze the efficient export for bulky yet abundant cargos from the ER. SEC16A and TANGO/TALI that reside in the ERES harbor multiple COPII-interacting domains, thereby locally condensing cytosolic COPII proteins and potentially triggering phase separation. (C) COPII proteins collars at the neck of tubular structures, which are organized by TANGO1, for transporting bulky cargos like collagens. Malhotra V. Tailored assemblies of COPII proteins in secretion. J Cell Biol. 2024 223(8):e202404013. PMID: 38958655;