Part of the nuclear pore complex. Has a critical role in nucleocytoplasmic transport. May serve as a docking site in the receptor-mediated import of substrates across the nuclear pore complex. Homodimer. Part of the nuclear pore complex (NPC). Interacts with NUP88. Interacts with ZFP36; this interaction increases upon lipopolysaccharide (LPS) stimulation. Interacts with DDX19. Interacts with XPO1. Interacts with XPO5. Cytoplasmic side of the nuclear pore complex. Contains FG repeats. 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. FG repeat regions are highly flexible and lack ordered secondary structure. The overall conservation of FG repeats regarding exact sequence, spacing, and repeat unit length is limited. The beta-propeller contains long interblade connector loops, and mediates interaction with DDX19B. Probably glycosylated as it reacts with wheat germ agglutinin (WGA).