The Nuclear Transport Factor Karyopherin β Binds Stoichiometrically to Ran-GTP and Inhibits the Ran GTPase Activating Protein
Copyright policy )The Nuclear Transport Factor Karyopherin β Binds Stoichiometrically to Ran-GTP and Inhibits the Ran GTPase Activating Protein
The heterodimeric karyopherin functions in targeting a nuclear localization sequence (NLS)-containing protein to the nuclear pore complex followed by Ran-GTP and p10-mediated translocation of the NLS protein into the nucleoplasm. It was shown recently that Ran-GTP dissociated the karyopherin heterodimer and, in doing so, associated with karyopherin beta (Rexach, M., and Blobel, G. (1995) Cell 83, 683-692). We show here, using all recombinant yeast proteins expressed in Escherichia coli, that karyopherin beta binds to Ran-GTP and inhibits GTP hydrolysis stimulated by RanGAP (the Ran-specific GTPase activating protein). Inhibition of RanGAP-stimulated GTP hydrolysis by karyopherin beta was dependent on karyopherin beta concentration relative to Ran-GTP. Complete inhibition of RanGAP was observed at karyopherin beta concentrations that were equimolar to Ran-GTP. In gel filtration experiments, we found Ran-GTP and karyopherin beta to form a stoichiometric complex. Ran-GDP bound only weakly to karyopherin beta. We propose that stoichiometric complex formation between karyopherin beta and Ran-GTP renders Ran-GTP inaccessible to RanGAP.
- Rockefeller University United States
- New York University United States
- Howard Hughes Medical Institute United States
Cell Nucleus, Base Sequence, GTPase-Activating Proteins, Genes, Fungal, Molecular Sequence Data, Restriction Mapping, Nuclear Proteins, Proteins, Saccharomyces cerevisiae, beta Karyopherins, Guanosine Diphosphate, Polymerase Chain Reaction, Recombinant Proteins, Kinetics, Protein Biosynthesis, Chromatography, Gel, Guanosine Triphosphate, Cloning, Molecular, DNA Primers, Protein Binding
Cell Nucleus, Base Sequence, GTPase-Activating Proteins, Genes, Fungal, Molecular Sequence Data, Restriction Mapping, Nuclear Proteins, Proteins, Saccharomyces cerevisiae, beta Karyopherins, Guanosine Diphosphate, Polymerase Chain Reaction, Recombinant Proteins, Kinetics, Protein Biosynthesis, Chromatography, Gel, Guanosine Triphosphate, Cloning, Molecular, DNA Primers, Protein Binding
selected citations These citations are derived from selected sources.This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).128 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 1% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 1%
Citations provided by BIP!Popularity provided by BIP!