Required for the export of mRNAs containing poly(A) tails from the nucleus into the cytoplasm. (Microbial infection) In case of infection by HIV-1, it may participate in the docking of viral Vpr at the nuclear envelope. Probable component of the nuclear pore complex (NPC). Interacts with nuclear export protein NXF1 (PubMed:10228171). Interacts with GLE1. Able to form a heterotrimer with NUP155 and GLE1 in vitro (PubMed:16000379). Interacts with XPO1 (PubMed:10358091). (Microbial infection) Interacts with the HIV-1 virus proteins Rev and Vpr. The interaction with HIV-1 Rev, a protein that mediates nuclear export of unspliced viral RNAs, suggests that its function may be bypassed by the HIV-1 virus. Excluded from the nucleolus. Ubiquitously expressed. The FG repeats are interaction sites for karyopherins (importins, exportins) and form probably an affinity gradient, guiding the transport proteins unidirectionally with their cargo through the NPC. O-glycosylated.