The formation of a macromolecular complex between the COPII coat proteins and proteins and/or lipoproteins that are going to be transported by the COPII vesicle to the Golgi. [ GOC:dph GOC:tb GOC:lb GOC:ascb_2009 ]
Synonyms: cargo loading into COPII vesicle cargo loading into COPII-coated vesicle cargo selection into COPII-coated vesicle