How cells resist mechanical stress
Published: Wednesday, Jul 24th 2024, 12:00
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Scientists from Switzerland and France have used cryo-electron microscopy to observe how cells withstand pressure and mechanical stress. The study published in the journal "Nature" shows that, depending on the conditions, small membrane areas can stabilize different lipids to trigger specific reactions.
Cells are surrounded by a membrane - the plasma membrane - which acts as a physical barrier but must be malleable. A team from the University of Geneva (UNIGE), in collaboration with the University of Freiburg and the Institute of Structural Biology in Grenoble (F), has investigated how the components of this membrane interact with each other so that its biophysical properties remain optimal.
"Until now, it was not possible for us to study the lipids in their natural environment within the membranes using the available techniques. Thanks to the Dubochet Center for Imaging at the Universities of Geneva, Lausanne, Bern and EPFL, we were able to overcome this challenge using cryo-electron microscopy," explains Robbie Loewith, Full Professor at the Department of Molecular and Cellular Biology at UNIGE.
With this technique, samples can be frozen at -200°C in order to capture the membranes in their original state and view them under an electron microscope. The scientists used baker's yeast (Saccharomyces cerevisiae), a model organism in which most of the basic cellular processes are similar to those of higher organisms.
This study focused on iceosomes, protein complexes in the cell membranes of yeasts. These eisosomes are able to secrete or store proteins and lipids. In this way, they help cells to resist and/or signal membrane damage according to previously unknown processes.
The scientists observed that the lipid organization of these microdomains is altered in response to mechanical stress. "We found that when the protein network of the Eisosome is stretched - for example by mechanical pressure - the complex arrangement of lipids in the microdomains is altered," Jennifer Kefauver, first author of the study, is quoted as saying.
The study reveals a molecular mechanism by which mechanical stress can be converted into biochemical signals via protein-lipid interactions with unprecedented precision, UNIGE concludes. This work opens up ways to investigate the crucial role of membrane compartmentalization in the response to different types of stress to which cells may be exposed.
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