New yeast prion helps cells survive

April 23, 2012
MOD+ yeast contain Mod5 aggregates (upper) and acquire resistance to an antifungal agent, fluconazole (lower). Credit: RIKEN

One of the greatest mysterious in cellular biology has been given a new twist thanks to findings reported in Science. Researchers at the RIKEN Brain Science Institute show that prions, proteins that transmit heritable information without DNA or RNA, can contribute to drug resistance and cellular adaptation. Their discovery of a yeast prion with these properties demonstrates the active role of the prion conversion in cellular fitness adaptation, providing new insights into the potentially broader function of prions in living organisms.

Since their discovery in the 1960s, the class of misfolded proteins known as prions has posed a fundamental challenge to the foundation of : the idea that heritable information flows from DNA and RNA to protein, but never from protein to any other molecule. Contrary to this rule, prions are able to transmit information from one molecule to another through the transmission of their misfolded shape, with devastating consequences in diseases such as and Creutzfeldt-Jakob disease. The broader implications of this unusual transmission mechanism, however, are not well understood.

Among these implications, research on yeast prions has suggested that beyond their well-known role in diseases, some prions may confer survival advantages by helping organisms respond to environmental stress. To explore this idea, the BSI research team screened a wide range of different genes in for previously-undiscovered prions. Out of 6000 genes screened, they found a new yeast prion protein "Mod5" with the unusual property that it lacks the glutamine and asparagine-rich amino acid sequences characteristic of other yeast prions. Sequences like these are thought to contribute to forming amyloid aggregates, the mechanism by which prions propagate.

Despite lacking these sequences, Mod5 forms amyloid aggregates just like other yeast prions. Unlike the destructive role such aggregates play in well-known prion diseases, however, the researchers showed that Mod5 aggregates actually help the yeast, by granting it cellular resistance to antifungal agents. This advantage is so important that the yeast actually increases prion conversion when the pressure is on, as the researchers found when they applied antifungal drugs to the yeast.

These results demonstrate that the Mod5 yeast prion contributes to cell survival under environmental stress, through selection playing a key role in evolutionary adaptation. This insight marks a breakthrough in our understanding of the evolutionary role of prions and their unique form of inheritance, promising new avenues in the battle to contain and treat some of the world's most dangerous infectious diseases.

Explore further: Cellular stress can induce yeast to promote prion formation

Related Stories

Cellular stress can induce yeast to promote prion formation

July 23, 2011
It's a chicken and egg question. Where do the infectious protein particles called prions come from? Essentially clumps of misfolded proteins, prions cause neurodegenerative disorders, such as mad cow/Creutzfeld-Jakob disease, ...

Study finds two gene classes linked to new prion formation

May 26, 2011
Unlocking the mechanisms that cause neurodegenerative prion diseases may require a genetic key, suggest new findings reported by University of Illinois at Chicago distinguished professor of biological sciences Susan Liebman.

Recommended for you

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

Engineered liver tissue expands after transplant

July 19, 2017
Many diseases, including cirrhosis and hepatitis, can lead to liver failure. More than 17,000 Americans suffering from these diseases are now waiting for liver transplants, but significantly fewer livers are available.

Lunatic Fringe gene plays key role in the renewable brain

July 19, 2017
The discovery that the brain can generate new cells - about 700 new neurons each day - has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan and Dan Duncan ...

New animal models for hepatitis C could pave the way for a vaccine

July 19, 2017
They say that an ounce of prevention is worth a pound of cure. In the case of hepatitis C—a disease that affects nearly 71 million people worldwide, causing cirrhosis and liver cancer if left untreated—it might be worth ...

Omega-3 fatty acids fight inflammation via cannabinoids

July 18, 2017
Chemical compounds called cannabinoids are found in marijuana and also are produced naturally in the body from omega-3 fatty acids. A well-known cannabinoid in marijuana, tetrahydrocannabinol, is responsible for some of its ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.