The import of proteins into the nucleus proceeds through the nuclear pore complex. Cytoplasmic proteins with a nuclear localization signal (NLS) bind to an importin-alpha/importin-beta heterodimer.
The trimeric complex docks to the cytoplasmic periphery of the nuclear pore complex and is subsequently translocated through as a single entity. The import reaction is terminated by the direct binding of RAN (MIM.601179) to KPNB, which dissociates the importin heterodimer.
Members
KPNAs
KPNBs
References
Harel A, Forbes DJ. Importin beta: conducting a much larger cellular symphony. Mol Cell. 2004 Nov 5;16(3):319-30. PMID: 15525506