Required for the export of mRNAs containing poly(A) tails from the nucleus into the cytoplasm. May be involved in the terminal step of the mRNA transport through the nuclear pore complex (NPC) (By similarity). Associated with the NPC, it however may not be a stable component of the NPC complex since it shuttles between the nucleus and the cytoplasm. Interacts with nuclear pore complex proteins NUP155 and NUPL2 (By similarity). Shuttles between the nucleus and the cytoplasm. Shuttling is essential for its mRNA export function. Belongs to the GLE1 family.