Group picture of the participants of the Bombannes Summer School 2024, mostly wearing event T-shirts. Copyright: organisers
Bombannes Summer School Educated 42 Students
15th January 2025
Figure: Unified state diagram for the fluidization transition. For small deformation amplitudes, soft systems exhibit solid-like dynamics (blue points) with low fluidity, namely very large spontaneous relaxation times. As the deformation amplitude increases, soft systems undergo the fluidization transition (gray points), characterized by the coexistence of two types of dynamics (solid and fluid). They are eventually fluidized at very large deformations, where the microscopic dynamics resemble those of a liquid. (Copyright © 2023: the authors)
Uncovering the Microscopic Origin of Fluidization
29th January 2025

Novel Technique to Measure Properties of Sub-cellular Compartments

Scientists from SoftComp partner University of Durham, UK, from University of Warwick, UK, and University of Bergen, Norway. have developed a new technique to measure the properties of biomolecular condensates, which are cellular sub-compartments that play a crucial role in various cellular processes, including stress response and as reaction crucibles. Unlike traditional organelles, biomolecular condensates lack a lipid membrane, allowing them to form and decompose rapidly in response to changes in the cellular environment.

The researchers developed a high-throughput technique based on Flicker Spectroscopy to measure the interfacial tension and bending rigidity of condensates in live cells. By analysing the shape fluctuations of condensates in confocal microscopy images, they were able to determine the mechanical properties of these sub-cellular compartments. This approach allows for the measurement of whole populations of tens of thousands of condensates, a significant improvement over existing methods.

Figure 1: The formation of stress granules in human cells upon the addition of Sodium Arsenite. Green regions show the location of G3BP, a protein which is known to localise in stress granules. Scale bar: 20 μm. Copyright: Published in Law J. O. et. al., Sci. Adv., 9, eadg0432 (2023) under a Creative Commons Attribution 4.0 International License.

Figure 1: The formation of stress granules in human cells upon the addition of Sodium Arsenite. Green regions show the location of G3BP, a protein which is known to localise in stress granules. Scale bar: 20 μm.
Copyright: Published in Law J. O. et. al., Sci. Adv., 9, eadg0432 (2023) under a Creative Commons Attribution 4.0 International License.

The study, which focused on stress granules, revealed that interfacial tension and bending rigidity can vary by up to four orders of magnitude at the population level. However, the flicker spectroscopy technique is sensitive enough to distinguish between stress granules induced by different reagents or with different compositions, providing new insights into the behaviour of these viscoelastic droplets.

Figure 2: Interfacial tension and bending rigidity can be determined by measuring the shape fluctuations of condensates. (a) The boundary fluctuations of a single stress granule over the course of 40 seconds. The red dashed line shows the time-averaged base shape of the granule. (b) An example fluctuation spectrum of a single stress granule, as measured using flicker spectroscopy. Black crosses indicate experimental data; lines indicate fits using three theoretical models. Only the model which includes contributions from both interfacial tension and bending rigidity is in good agreement with the experimental spectrum. Copyright: Published in Law J. O. et. al., Sci. Adv., 9, eadg0432 (2023) under a Creative Commons Attribution 4.0 International License.

Figure 2: Interfacial tension and bending rigidity can be determined by measuring the shape fluctuations of condensates. (a) The boundary fluctuations of a single stress granule over the course of 40 seconds. The red dashed line shows the time-averaged base shape of the granule. (b) An example fluctuation spectrum of a single stress granule, as measured using flicker spectroscopy. Black crosses indicate experimental data; lines indicate fits using three theoretical models. Only the model which includes contributions from both interfacial tension and bending rigidity is in good agreement with the experimental spectrum.
Copyright: Published in Law J. O. et. al., Sci. Adv., 9, eadg0432 (2023) under a Creative Commons Attribution 4.0 International License.

The findings may have important implications for our understanding of cellular biology and the role of biomolecular condensates in various diseases, including neurodegenerative disorders such as Amyotrophic lateral sclerosis (ALS). By shedding light on the mechanical properties of condensates, this research paves the way for further studies into the complex interactions between these sub-cellular compartments and their surroundings.

Read more:
Law J. O. et. al., Sci. Adv., 9, eadg0432 (2023)

SoftComp partner:
University of Durham

 

 

Research Gate
Research Gate

Cookies

This site uses Cookies in order to improve our service. By continuing, you are agreeing to the terms of our "Cookie Policy". Read more