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). 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 NUP42. Isoform 2 does not interact with NUP42. Able to form a heterotrimer with NUP155 and NUP42 in vitro. Shuttles between the nucleus and the cytoplasm (PubMed:12668658). Shuttling is essential for its mRNA export function (PubMed:12668658). Shuttles between the nucleus and the cytoplasm (PubMed:12668658). In the nucleus, isoform 1 localizes to the nuclear pore complex and nuclear envelope (PubMed:12668658). Shuttling is essential for its mRNA export function (PubMed:12668658). The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Major isoform. Belongs to the GLE1 family.