Enables protein heterodimerization activity. Predicted to be involved in retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum. Predicted to act upstream of or within vesicle-mediated transport. Located in endoplasmic reticulum. Is expressed in head; optic cup; and retina. Orthologous to human BNIP1 (BCL2 interacting protein 1).