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Proteomic analysis of nucleoporin interacting proteins
N P Allen1, L Huang, A Burlingame
1Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA.
The Journal of Biological Chemistry
|June 2, 2001
Summary
Researchers mapped protein interactions within the Saccharomyces cerevisiae nuclear pore complex, revealing how karyopherins navigate transport pathways. This study details specific nucleoporin interactions, crucial for understanding nucleocytoplasmic transport mechanisms.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The nuclear pore complex (NPC) in Saccharomyces cerevisiae is a large molecular machine regulating transport between the nucleus and cytoplasm.
- Nucleoporins (Nups) with FG-peptide repeats (FG Nups) are hypothesized to act as interaction sites for transport factors.
- Karyopherins mediate the transport of molecules through the NPC.
Purpose of the Study:
- To investigate the specific protein-nucleoporin interactions at individual FG Nups.
- To understand the role of these interactions in karyopherin-mediated nucleocytoplasmic transport.
- To elucidate the influence of GTP-bound Gsp1p on these interactions.
Main Methods:
- Utilized immobilized nucleoporins and yeast extracts to sample protein interactions.
- Employed mass spectrometry to identify interacting proteins.
- Manipulated Gsp1p-GTP concentration to mimic nucleoplasmic conditions.
Main Results:
- Identified reproducible binding patterns between proteins and FG Nups.
- Found that specific FG Nups (Nup42p, Nup49p, Nup57p, Nup100p, Nup116p) interact broadly with karyopherins.
- Observed that FXFG nucleoporins (Nup1p, Nup2p, Nup60p) show selective binding, primarily to Kap95p.Kap60p.
- Demonstrated that elevated Gsp1p-GTP enhances exportin binding and reduces importin binding to FG Nups.
Conclusions:
- Gsp1p-GTP significantly influences karyopherin-nucleoporin interactions.
- Provided insights into the dynamic nature of transport pathways within the NPC.
- Established a foundational map of karyopherin routes across the nuclear pore complex.