The nuclear pore complex (NPC) is a structure that spans the nuclear envelope and provides a conduit between the nucleus and cytoplasm for the nucleocytoplasmic transport of macromolecules. The main components of the NPC are nucleoporins. There are about 30 different human Nups that have been identified. Nup50 (also called Npap60) appears to not be a fixed structural component of the NPC. Nup50 has been shown to be a component of the importin complex, a protein carrier complex that imports cargo from the cytoplasm to the nucleus through the NPC. In this complex, Nup50 appears to have importance in the late stages of import and functions in complex disassembly and importin recycling.