In concert with ran, required for proper eye development (PubMed:25946333). May be involved in the expression of early eye marker genes (PubMed:19167377). Interacts with banf1-a and banf1-b. Interacts with ran-gtp. Localization in the nuclear membrane is essential for its function. Colocalizes with lamins and banf1-a/b at the nuclear envelope. Expressed both maternally and zygotically. At the early gastrula stage, expressed mainly in the entire animal hemisphere. During neurulation, its expression becomes restricted to the anterior neuroectoderm. At the tailbud stage, expressed in various anterior regions including the anterior central nervous system (CNS), otic vesicles, and branchial arches. The transmembrane domains are required and sufficient for its oligomerization. Phosphorylated. Morpholino knockdown results in defects in eye development, reduced expression of early eye marker genes rax, tbx3, six3 and pax6 and reduction of cell density at the neurula stage. Co-knockdown of nemp1b and ran elicits reduction of cell density and eye defects more significantly than the individual knockdown of either one. Belongs to the NEMP family.