ER selective transport: five major interdependent strategies

Cargo capture: receptor-mediated export of proteins from the ER to the Golgi complex in coatamer protein II (COPII) vesicles. Bulk flow: some proteins and lipids are included in COPII vesicles by default Retention: prevents proteins from entering the transport vesicles Retrieval: retrograde transport from the ER-Golgi intermediate compartment (ERGIC) /early Golgi back to the ER ERAD: cytosolic elimination of ER proteins that fail quality control