This structure acts on proteins that have been tagged by a sequence rich in lysine and arginine known as an NLS.
Domains on the surface of this structure can exclude certain particles via "entropic bristles" according to this structure's "virtual gate" model, or act as a molecular sieve in this structure's "selective phase" model.  Those aforementioned domains contain numerous phenylalanine-glycine motifs. This octagonally symmetric structure consists of annular subunits which extend "spokes" towards its center and possess a "basket" inside the lumen. The function carried out by these structures is initiated by the binding of RanGTP to a karyopherin. This structure acts on proteins that have been tagged by a sequence rich in lysine and arginine known as an NLS. Importins and exportins mediate transport through these structures, which span a membrane that is structurally supported by lamins. For 10 points, name these complexes through which materials are transported in and out of the nucleus.
Domains on the surface of this structure can exclude certain particles via "entropic bristles" according to this structure's "virtual gate" model, or act as a molecular sieve in this structure's "selective phase" model.  
nuclear pore complex [or npc]