Required for normal Golgi function (PubMed:19536132, PubMed:30290151). Plays a role in SNARE-pin assembly and Golgi-to-ER retrograde transport via its interaction with SCFD1 (PubMed:19536132). . This is the function of Ensembl gene identifier ENSG00000103051 (COG4, component of oligomeric golgi complex 4).