Active transport of proteins and RNA into and out of the nucleus occurs via the nuclear pore complex (NPC). The NPC is formed by a multiprotein complex that includes nucleoporin proteins. Specific nuclear localization sequences found in proteins target proteins for active transport into the nucleus through the NPC. Nucleoporin p62 is the best characterized member of the family of nucleoporins found in the NPC. A tightly associated complex is formed by p62 and two other nucleoporins, p54 and p58. p54 binds to a carboxy-terminal coiled-coil domain of p62 and p58 binds to a dimer of p54. The amino-terminal domain of p62 contains a series of XFXFX repeats and is joined to the coiled-coil domain by a threonine-rich linker segment. The major role of p62 is maintenance of the structural integrity of NPCs.
