1. Nup2p dynamically associates with the distal regions of the yeast nuclear pore complex.
- Author
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Dilworth DJ, Suprapto A, Padovan JC, Chait BT, Wozniak RW, Rout MP, and Aitchison JD
- Subjects
- Binding Sites physiology, Cell Nucleus metabolism, Cytoplasm metabolism, Deoxyglucose pharmacology, Fungal Proteins genetics, Fungal Proteins metabolism, Green Fluorescent Proteins, Guanosine Triphosphate metabolism, Heat-Shock Proteins metabolism, Luminescent Proteins genetics, Nuclear Proteins genetics, Porins genetics, Protein Binding drug effects, Protein Binding physiology, Protein Structure, Tertiary physiology, Protein Transport physiology, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Saccharomyces, Sodium Azide pharmacology, Staphylococcus aureus genetics, beta Karyopherins, ran GTP-Binding Protein metabolism, Nuclear Pore metabolism, Nuclear Pore Complex Proteins, Nuclear Proteins metabolism, Porins metabolism, Saccharomyces cerevisiae Proteins
- Abstract
Nucleocytoplasmic transport is mediated by the interplay between soluble transport factors and nucleoporins resident within the nuclear pore complex (NPC). Understanding this process demands knowledge of components of both the soluble and stationary phases and the interface between them. Here, we provide evidence that Nup2p, previously considered to be a typical yeast nucleoporin that binds import- and export-bound karyopherins, dynamically associates with the NPC in a Ran-facilitated manner. When bound to the NPC, Nup2p associates with regions corresponding to the nuclear basket and cytoplasmic fibrils. On the nucleoplasmic face, where the Ran--GTP levels are predicted to be high, Nup2p binds to Nup60p. Deletion of NUP60 renders Nup2p nucleoplasmic and compromises Nup2p-mediated recycling of Kap60p/Srp1p. Depletion of Ran--GTP by metabolic poisoning, disruption of the Ran cycle, or in vitro by cell lysis, results in a shift of Nup2p from the nucleoplasm to the cytoplasmic face of the NPC. This mobility of Nup2p was also detected using heterokaryons where, unlike nucleoporins, Nup2p was observed to move from one nucleus to the other. Together, our data support a model in which Nup2p movement facilitates the transition between the import and export phases of nucleocytoplasmic transport.
- Published
- 2001
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