Export of proteins from the ER appears to involve default pathways (bulk flow) and selective mechanisms. Selective export depends on sorting signals in the protein – for example, FF, di-acidic and di-hydrophobic motifs. These have not been fully characterized and, in most cases, efficient export seems to require several regions of the protein. Hans-Peter Hauri and co-workers now provide the first complete map of export determinants for a type I membrane protein: ERGIC-53, a protein that cycles between the ER and the ER-Golgi intermediate compartment (ERGIC). Using endoglycosidase resistance to monitor export of ERGIC-53 mutants biochemically, they identify determinants in the cytoplasmic, lumenal and transmembrane regions of ERGIC-53 (see p. 4429). These include the F2 residue at the C-terminus (which interacts with the vesicle coat protein COPII), transmembrane residues that facilitate oligomerization and lumenal cysteine residues necessary for disulphide-mediated stabilization of ERGIC-53 oligomers. Importantly, the authors show that when these determinants are placed on a signal-less reporter protein it is efficiently exported. They conclude that the transmembrane and lumenal motifs cooperate to promote ERGIC-53 oligomerization, which is essential for efficient recruitment of the protein's C-terminus by the COPII export machinery.