Nup120 is conserved from fungi to plants to humans, and is homologous with the Nup160 of vertebrates. The nuclear core complex, or NPC, mediates macromolecular transport across the nuclear envelope. Deletion of the NUP120 gene causes clustering of NPCs at one side of the nuclear envelope, moderate nucleolar fragmentation and slower cell growth. The vertebrate NPC is estimated to contain between 30 and 60 different proteins. most of which are not known. Two important ones in creating the nucleoporin basket are Nup98 and Nup153, and Nup120, in conjunction with Nup 133, interacts with these two and itself plays a role in mRNA export. Nup160, Nup133, Nup96, and Nup107 are all targets of phosphorylation. The phosphorylation sites are clustered mainly at the N-terminal regions of these proteins, which are predicted to be natively disordered. The entire Nup107-160 sub-complex is stable throughout the cell cycle, thus it seems unlikely that phosphorylation affects interactions within the Nup107-160 sub-complex, but rather that it regulates the association of the sub-complex with the NPC and other proteins.