Scientists from the University of Geneva and the University of Fribourg have made significant strides in understanding how yeast cells sense and respond to physical stress on their membranes, shedding light on the critical role of membrane dynamics in cell survival.
Researchers from the University of Geneva (UNIGE), in collaboration with the University of Fribourg (UNIFR) and the Institut de biologie structurale de Grenoble (IBS), have made a breakthrough in the study of cell membranes. Using high-resolution cryo-electron microscopy, the team has observed how lipids and proteins in the plasma membrane of yeast cells interact and respond to mechanical stress. These findings, published in the journal Nature, confirm the existence of well-organized lipid domains within membranes and provide new insights into how these structures contribute to cellular survival.
Cell membranes, composed of lipids and proteins, serve as a critical barrier and are essential for maintaining the integrity and functionality of cells. However, their ability to adapt to external stresses while maintaining optimal conditions for cell growth is not fully understood. This study focused on a specific membrane microdomain that is scaffolded by a protein coat known as eisosomes. These structures play a critical role in helping cells resist and signal membrane damage through previously unknown processes.
‘‘Until now, the techniques available did not allow us to study lipids in their natural environment inside membranes. Thanks to the Dubochet Center for Imaging (DCI) at the Universities of Geneva, Lausanne, Bern, and the EPFL, we have been able to meet this challenge by using cryo-electron microscopy,’’ explained Robbie Loewith, a full professor at UNIGE and leader of the study. This advanced technique allows researchers to observe membrane structures in their native state by freezing samples at -200°C.
A significant step forward
The team used baker’s yeast (Saccharomyces cerevisiae), a model organism widely used in research due to its ease of growth and genetic manipulation. The study revealed that when the eisosome protein lattice is stretched, it triggers a reorganization of lipids within the microdomains, likely leading to the release of signaling molecules that help the cell adapt to stress.
‘‘Our study reveals a molecular mechanism by which mechanical stress can be converted to biochemical signaling via protein-lipid interactions in unprecedented detail,’’ said Jennifer Kefauver, a post-doctoral researcher and first author of the study.
This research opens new avenues for exploring how membrane compartmentalization allows cells to perform specialized biochemical functions, particularly in response to various stresses. The research represents a significant step forward in our understanding of cell membrane dynamics and their role in cell communication and survival.
