Prions, pathogens that trigger catastrophic chain reactions of misfolded proteins in various diseases, can help yeast to survive in harsh conditions.

Yeast assume complex multicellular structures when resources are scarce, such as long-branching stalks when cells are starved of nitrogen, or ridges when fermentable carbon is in short supply. Researchers led by Randal Halfmann at the University of Texas Southwestern Medical Center in Dallas report that such adaptive formations occur when a protein called Mot3 forms prions, drastically changing its shape and causing other Mot3 proteins to convert to this state. The researchers show that a non-fermentable carbon source such as ethanol induces Mot3 to form prions, and a lack of oxygen eliminates them. Thus, prions can mediate how yeast cells act cooperatively in response to their environment.

Cell 153, 153–165 (2013)