PNAS: Hungry yeast are tiny living thermometers

Cell membranes are vital to our cells

Cell membranes help cells perform tasks such as breaking down food into energy, producing and breaking down proteins, tracking environmental conditions, sending signals and deciding when to divide

Biologists have long tried to understand exactly how cell membranes do these different types of jobs

In a paper published Jan.

"Previous work has shown that these domains can be seen in the membranes of living yeast cells," said the study's lead author, Chantelle LeveilIe, a PhD student in chemistry at the University of Washington

"The answer is yes!"

Past research has shown that when sugar is plentiful, a yeast cell's vacuole -- an important storage and signaling organelle -- grows so large that its membranes appear homogeneous under a microscope

In the new study, Leveille and her colleagues sought to understand whether yeast can actively regulate phase separation

These experiments show that yeast cells remain phase-separated in the tonoplast until the temperature rises to about 25 degrees above their growth temperature

Phase separation of the tonoplast may play an important role in yeast, she added

"This result suggests that membrane phase separation in yeast may be a two-way gate," Leveille said.

Future studies could identify other membrane components that affect the phase separation ability of tonoplast membranes, and the consequences of their phase separation

"Phase separation in the vacuole occurs when the yeast cell's food supply is exhausted and it needs to stop dividing

In cells from yeast to humans, protein complexes embedded in the cell membrane influence cell behavior

"Phase separation may be a common, reversible mechanism that modulates many, many types of cellular properties," Keller said
.

article title

Yeast cells actively tune their membranes to phase separate at temperatures that scale with growth temperatures