Importin 8 is a 1037aa nuclear protein with a RAN binding site. It belongs to RAN-binding protein super family and hence shares an N-terminal sequence motif with importin-beta that appears to account for RAN GTP binding. It binds to the nuclear pore complex (NPC) and is well known as a transport carrier that mediates nuclear import of ribosomal proteins with a classical nuclear localization signal. Importin 8 works by binding to the nuclear pore complex and, along with RANGTP and RANBP1, inhibits the GAP stimulation of the RAN GTPase. Along with transportin it also helps in the nuclear import of SRP19.