Importin 13 (IPO13)

IPO13 encodes a member of the importin-beta family of nuclear transport proteins. The encoded protein mediates the import of specific cargo proteins from the cytoplasm to the nucleus and is dependent on the Ras-related nuclear protein-GTPase system. The encoded protein is also involved in nuclear export of the eukaryotic translation initiation factor 1A.By mass spectrometry, Mingot et al. (2001) identified several proteins from HeLa cell extract that bound specifically to IPO13; these included ribosomal protein L5, RBM8, and UBC9 (UBE2I). Each could be displaced by RanGTP and are most likely import substrates. The translation initiation factor eIF1A bound only in the presence of RanGTP and is a potential IOP13-specific export substrate.