Related Experiment Video
Updated: Sep 27, 2025
12:13
Single-Molecule Imaging of Nuclear Transport
Published on: June 9, 2010
13.5K
Barriers to Diffusion in Cells: Visualization of Membraneless Particles in the Nucleus
Leonel Malacrida1,2,3, Per Niklas Hedde1, Belen Torrado1,4
1Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA.
Biophysicist (Rockville, Md.)
|April 13, 2022
Summary
This study introduces a new method using 2D pair correlation function (2D-pCF) to detect transient diffusion barriers within cells. The technique visualizes how molecular movement is restricted, aiding in understanding cell organization.
Area of Science:
- Cell biology
- Biophysics
- Molecular dynamics
Background:
- Transient barriers, physical or thermodynamic, are crucial for cell supramolecular organization.
- Demonstrating phase separation-induced barriers experimentally is challenging due to their transient and invisible nature.
Purpose of the Study:
- To present a novel approach for experimentally demonstrating transient diffusion barriers within cells.
- To introduce the 2-dimensional pair correlation function (2D-pCF) as a tool for analyzing spatial connectivity and diffusion.
- To provide an educational model for explaining diffusion barrier measurements in biological contexts.
Main Methods:
- Analysis of spatial connectivity using the 2-dimensional pair correlation function (2D-pCF).
- Measurement of enhanced green fluorescent protein diffusion in live cells.
- Characterization of molecular movement patterns in relation to cellular structures.
Main Results:
- The 2D-pCF method successfully detected discontinuities in molecular movement at the nucleolus surface.
- Diffusion barriers were observed to restrict connectivity at shorter distances.
- Increased connectivity was noted at longer distances or times, suggesting molecular trajectories around obstacles.
Conclusions:
- The 2D-pCF analysis is an effective method for visualizing and quantifying transient diffusion barriers in cells.
- This approach offers insights into how cellular structures influence molecular transport and organization.
- The findings contribute to a better understanding of supramolecular assembly and phase separation in biological systems.
Related Concept Videos
01:24Protein Diffusion in the Membrane
4.7K
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
4.7K
01:19Protein Dynamics in Living Cells
2.3K
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
2.3K
01:34Nuclear Protein Sorting
4.9K
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...
4.9K