AMINO-TERMINAL SEQUENCES THAT DIRECT NUCLEOPORIN NUP153 TO THE INNER SURFACE OF THE NUCLEAR-ENVELOPE

Nup153 is a large O-linked glycoprotein that is a component of the bas ket-like structure that forms the nucleoplasmic face of nuclear pore c omplexes (NPCs). The Nup153 molecule has a tripartite structure consis ting of N- and C-terminal domains flanking a central zinc finger domai n. All of the targeting and assembly information contained within Nup1 53 is contributed by the N-domain. In fact this region of the molecule can target a cytosolic protein, pyruvate kinase, to the nucleoplasmic face of the NPC. The zinc finger and C-terminal domains appear to hav e no role in these targeting and assembly activities. Deletion analysi s reveals that there are two distinct regions within the Nup153 N-doma in that contain different targeting functions. One of these is directl y involved in assembly into the NPC while a second overlapping region may target Nup153, as well as other reporter molecules, to the inner f ace of the nuclear envelope.