Involved in transport from the endoplasmic reticulum to the Golgi apparatus. Required to maintain SEC16A localization at discrete locations on the ER membrane perhaps by preventing its dissociation. SAR1A-GTP-dependent assembly of SEC16A on the ER membrane forms an organized scaffold defining endoplasmic reticulum exit sites (ERES) (By similarity).
Subcellular locations: Endoplasmic reticulum, Golgi apparatus