Proteins that carry a nuclear localization signal (NLS) are transported into the nucleus by the importin-alpha/beta heterodimer.Importin-alpha binds the NLS, while importin-beta mediates translocation through the nuclear pore complex.After translocation, RanGTP binds importin-beta and displaces importin-alpha.Importin-alpha must then be returned to the cytoplasm, leaving the NLS protein behind.The protein encoded by this gene binds strongly to NLS-free importin-alpha, and this binding is released in the cytoplasm by the combined action of RANBP1 and RANGAP1.In addition, the encoded protein may play a role both in apoptosis and in cell proliferation.[provided by RefSeq]