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How evolution fine tunes molecular mechanisms to create and maintain membrane diversity between species

The cell membrane is a fundamental biological structure. These lipid layers surround and organize every cell, controlling everything from signaling to transport. But for membranes to function properly, ...

How evolution fine tunes molecular mechanisms to create and maintain membrane diversity between species
When membranes become too rigid, Mga2 is activated. It is cleaved from the membrane and switches on a gene that produces Ole1, an enzyme that makes unsaturated fatty acids, restoring balance. Each yeast species has a different threshold for when the membrane needs adjusting. Credit: The Francis Crick Institute

The cell membrane is a fundamental biological structure. These lipid layers surround and organize every cell, controlling everything from signaling to transport. But for membranes to function properly, their physicochemical properties must sit within a narrow range: for instance, not too rigid or too fluid.

Since environmental conditions such as variation in dietary lipids or fluctuating temperature may alter membrane fluidity, organisms must regulate themselves. Different organisms have evolved different preferences for the properties of their cellular membranes.

For Snezhka Oliferenko, who leads the Crick's Comparative Biology of Mitotic Division Lab, biological membranes are the perfect system for studying the evolution of cellular diversity across species. "By focusing on how cells build and regulate their membranes, we can uncover how diversity arises," she explains.

"We want to understand how changes in lipid biochemistry affect cell makeup, cell behavior and ultimately, cell evolution."

In their latest study, published in Genes & Development, Oliferenko and her team examined two closely related fission yeast species, Schizosaccharomyces pombe and Schizosaccharomyces japonicus, which share a very similar genetic makeup but are biologically very different.

A key factor in membrane fluidity is the level of "unsaturation," which depends on the type of lipids present. Membranes with a higher proportion of unsaturated lipids that have cis-double bonds in their fatty acid tails are more fluid because kinks in the tails prevent tight packing of lipids. S. pombe produces more flexible, fluid membranes, whereas S. japonicus membranes are more ordered and rigid. These differences provide a natural comparison for understanding how cells can evolve and maintain distinct physicochemical properties of their membranes.

Lead author Elisa Gomez-Gil studied both species in detail, analyzing the lipid composition of the membranes under different conditions and the activity of the genes that control lipid production. "We focused on a key feedback loop involving a protein called Mga2, which sits in the membrane and acts as a sensor," Gomez-Gil describes. "When membranes become too rigid, Mga2 is activated. It is cleaved from the membrane and switches on a gene that produces Ole1, an enzyme that makes unsaturated fatty acids, restoring balance."

Gomez-Gil compared how this system behaves in each yeast species, then went a step further by editing parts of this feedback loop to test how each component behaved in a different biological context. "This allowed us to isolate which elements set the sensitivity of the system and understand how those elements have been tuned through evolution," she adds.

They showed that each species has a different threshold for when the membrane needs adjusting, with S. pombe having a low tolerance for membrane rigidity, and that this was due to two key evolutionary shifts. Small differences in the part of the Mga2 protein that sits next to the membrane alter how readily it is cleaved when the membrane becomes too rigid. At the same time, changes in the Ole1 gene set the baseline level of the response, determining how much of the enzyme is produced once the system is activated.

This shows that the sensor and its downstream response have evolved together, ensuring the system still works even as the underlying membrane biochemistry shifts.

"We often think of evolution as creating new biological machinery," adds Oliferenko. "But in many cases, it's fine-tuning what's already there. Much of the diversity we see across species may not come from entirely new genes or pathways, but from subtle shifts in how shared systems are regulated."

Publication details

Elisa Gomez-Gil et al, Adaptation of eukaryotic membrane homeostasis to species-specific cellular lipid landscapes, Genes & Development (2026). DOI: 10.1101/gad.353500.125 genesdev.cshlp.org/content/ear … .353500.125.abstract

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Lisa Lock

Lisa Lock

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Citation: How evolution fine tunes molecular mechanisms to create and maintain membrane diversity between species (2026, August 6) retrieved 6 August 2026 from https://phys.org/news/2026-08-evolution-fine-tunes-molecular-mechanisms.html

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