Predicted to enable GTPase activator activity. Acts upstream of or within cartilage development; embryonic neurocranium morphogenesis; and erythrocyte development. Predicted to be located in cytoplasmic vesicle; cytosol; and endoplasmic reticulum membrane. Predicted to be part of COPII vesicle coat. Predicted to be active in endoplasmic reticulum exit site. Human ortholog(s) of this gene implicated in Cowden syndrome 7 and congenital dyserythropoietic anemia type II. Orthologous to human SEC23B (SEC23 homolog B, COPII coat complex component).