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Updated: Aug 9, 2026
12:13
Single-Molecule Imaging of Nuclear Transport
Published on: June 9, 2010
Receptor-mediated substrate translocation through the nuclear pore complex without nucleotide triphosphate hydrolysis
L Englmeier1, J C Olivo, I W Mattaj
1European Molecular Biology Laboratory, Meyerhofstrasse, 1 D-69117, Heidelberg, Germany.
Current Biology : CB
|January 16, 1999
Summary
Nuclear transport of macromolecules is energy-independent. The translocation of substrate-receptor complexes across the nuclear pore complex (NPC) does not require energy, with energy supplied during receptor recycling.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Nuclear transport of macromolecules is crucial for cellular function.
- This process occurs through nuclear pore complexes (NPCs) and typically requires energy.
- Nucleocytoplasmic transport receptors, like importin beta family members, mediate substrate translocation.
Purpose of the Study:
- To investigate the energy requirements of nucleocytoplasmic transport.
- To determine if translocation across the NPC is an energy-dependent step.
Main Methods:
- Developed an in vitro system using permeabilised cells.
- Studied nuclear export mediated by CRM1/Exportin1 and nuclear import mediated by transportin.
- Utilized non-hydrolysable nucleotide triphosphate (NTP) analogues and assessed the role of the Ran GTPase.
Main Results:
- CRM1-mediated export and transportin-mediated import across the NPC occurred without NTP hydrolysis.
- Non-hydrolysable NTP analogues supported CRM1-mediated translocation in a single round.
- Single importin-mediated import events proceeded without hydrolysable NTPs or the Ran GTPase.
Conclusions:
- Contrary to prior conclusions, NPC translocation is energy-independent.
- NTP hydrolysis is not required for the translocation of substrate-receptor complexes.
- Energy for transport against a gradient is supplied by receptor recycling in the cytoplasm.
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