May be involved in endoplasmic reticulum exit trafficking of proteins. Interacts with PRM9. Binds to SEC23/24 of COPII coated vesicles. Present with 1254 molecules/cell in log phase SD medium. Members of the DUP240 multigene family are specific to S.cerevisiae sensu strictu. Cells lacking all 10 DUP240 proteins show no obvious alterations in mating, sporulation and cell growth. Belongs to the DUP/COS family.