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Visualization of Protein-protein Interaction in Nuclear and Cytoplasmic Fractions by Co-immunoprecipitation and In Situ Proximity Ligation Assay
Published on: January 16, 2017
RanBP3 influences interactions between CRM1 and its nuclear protein export substrates
L Englmeier1, M Fornerod, F R Bischoff
1European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
EMBO Reports
|September 26, 2001
Summary
RanBP3 acts as a novel cofactor, enhancing CRM1-mediated nuclear export of proteins in eukaryotes. It stabilizes CRM1-export substrate interactions, facilitating cellular transport.
Area of Science:
- Molecular Biology
- Cell Biology
- Protein Transport
Background:
- CRM1 (Chromosome Region Maintenance 1) is a key nuclear transport receptor.
- CRM1 mediates the export of numerous proteins from the nucleus to the cytoplasm.
- The precise mechanisms regulating CRM1-mediated export are not fully understood.
Purpose of the Study:
- To investigate the role of RanBP3 (Ran-binding protein 3) in CRM1-mediated protein export.
- To elucidate the mechanism by which RanBP3 interacts with CRM1 and influences substrate export.
Main Methods:
- Biochemical assays to study protein interactions.
- In vitro experiments using permeabilized cells to assess nuclear export.
- Analysis of the effects of RanBP3 on CRM1-substrate binding affinities.
Main Results:
- RanBP3 directly interacts with CRM1 and forms a trimeric complex with CRM1 and RanGTP.
- RanBP3 does not bind CRM1 as an export substrate but stabilizes the CRM1-export substrate complex.
- Nuclear RanBP3 stimulates CRM1-dependent protein export in vitro.
- RanBP3 binding to CRM1 alters the receptor's affinity for different substrates.
Conclusions:
- RanBP3 functions as a novel cofactor in the CRM1-mediated nuclear export pathway.
- RanBP3 plays a critical role in the recognition and efficient export of specific CRM1 cargo proteins.
- This discovery provides new insights into the regulation of nuclear transport.
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