May be involved in membrane trafficking in the early secretory pathway. Homodimer. Expressed in the animal hemisphere at the four-cell stage. During gastrulation, expression becomes restricted to the prospective neuroectoderm. At the early tail bud stage, expressed in the head structure. At the tadpole stage, expressed in head and neural tissues including the otic vesicle and optic nerve. Expressed both maternally and zygotically.