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Exportin 7 defines a novel general nuclear export pathway
José-Manuel Mingot1, Markus T Bohnsack, Ursula Jäkle
1ZMBH, INF 282, Heidelberg, Germany.
The EMBO Journal
|July 30, 2004
Summary
RanBP16, now called exportin 7 (Exp7), is a nuclear transport receptor that exports proteins like p50RhoGAP and 14-3-3sigma from the nucleus. Exp7 has broad substrate specificity and distinct export signals compared to CRM1.
Area of Science:
- Cell biology
- Molecular biology
- Biochemistry
Background:
- Nuclear transport receptors, particularly the importin beta family, mediate most nucleocytoplasmic transport.
- RanBP16 is a nuclear transport receptor in higher eukaryotes with a previously unknown function.
Purpose of the Study:
- To elucidate the function of RanBP16 in nuclear transport.
- To characterize the cargo specificity and mechanism of RanBP16-mediated nuclear export.
Main Methods:
- Functional assays to determine RanBP16's role in protein localization.
- Analysis of RanBP16's interaction with cargo molecules.
- Characterization of nuclear export signals recognized by RanBP16.
Main Results:
- RanBP16 mediates the nuclear export of p50RhoGAP and 14-3-3sigma, confining their activity to the cytoplasm.
- RanBP16 demonstrates broad substrate specificity, suggesting a significant role in nuclear export.
- Exp7-dependent nuclear export signals differ from CRM1-dependent signals, involving folded motifs and basic residues.
Conclusions:
- RanBP16 functions as exportin 7 (Exp7), a nuclear export mediator with broad substrate specificity.
- Exp7 plays a crucial role in regulating the localization and function of specific proteins by mediating their nuclear export.
- Exp7 utilizes distinct mechanisms for cargo recognition and nuclear export compared to other known export pathways.