Plays a role in the organization of the endoplasmic reticulum exit sites (ERES), also known as transitional endoplasmic reticulum (tER). Required for secretory cargo traffic from the endoplasmic reticulum to the Golgi apparatus (PubMed:17192411, PubMed:21768384, PubMed:22355596). Involved in peroxisome biogenesis. Regulates the transport of peroxisomal biogenesis factors PEX3 and PEX16 from the ER to peroxisomes (PubMed:21768384). {ECO:0000269|PubMed:17192411, ECO:0000269|PubMed:21768384, ECO:0000303|PubMed:22355596}. This is the function of SEC16B (SEC16 homolog B, endoplasmic reticulum export factor, Ensembl gene identifier ENSG00000120341).