Related Experiment Video
Updated: Jun 10, 2026
12:13
Single-Molecule Imaging of Nuclear Transport
Published on: June 9, 2010
Facilitated transport and diffusion take distinct spatial routes through the nuclear pore complex
Jindriska Fiserova1, Shane A Richards, Susan R Wente
1Department of Biological and Biomedical Sciences, Durham University, Durham, DH1 3LE, UK.
Journal of Cell Science
|July 22, 2010
Summary
Nuclear pore complexes (NPCs) regulate transport. This study reveals distinct pathways within NPCs for import and export cargos, essential for cellular function.
Area of Science:
- Cell Biology
- Molecular Biology
- Biophysics
Background:
- Nuclear pore complexes (NPCs) control molecular traffic between the nucleus and cytoplasm.
- While NPC function is known, the precise mechanism of cargo translocation remains unclear.
Purpose of the Study:
- To directly visualize and determine the spatial localization of cargos during nuclear transport.
- To elucidate the translocation pathways within the NPC.
Main Methods:
- High-pressure freezing and low-temperature fixation to trap cargos in transit.
- Immunoelectron microscopy for precise cargo localization.
- Statistical modeling to analyze cargo distribution within the NPC.
Main Results:
- Import cargos were found near the NPC channel edge; mRNA export factors localized to the NPC center.
- Free diffusion of GFP showed random distribution, contrasting with specific cargo localization.
- Deletion of FG domains disrupted peripheral localization and caused transport defects.
Conclusions:
- Spatially distinct pathways exist within the NPC for different cargos.
- Nuclear transport route constraints are primarily biochemical, not structural.
- The peripheral pathway is crucial for facilitated nuclear import.
Related Concept Videos
01:34Nuclear Protein Sorting
Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
01:16Facilitated Diffusion
The plasma membrane, a critical structure in cellular biology, houses an array of transporters, or carrier proteins, interspersed within its lipid bilayer. These proteins play a crucial role in solute transport through facilitated diffusion, a form of passive diffusion that uses transporters to move the molecules across the membrane.
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
01:19Facilitated Transport
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a membrane via...
01:19Facilitated Transport
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a membrane via...
01:19Facilitated Transport
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a membrane via...
01:45Regulation of Nuclear Protein Sorting
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...