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: Prion propagates in foreign host

Related Stories

Prion propagates in foreign host

July 5, 2007

Prions -- infectious, oddly-folded proteins that are the main suspects in fatal neurodegenerative diseases such as Cruetzfeldt-Jakob and bovine spongiform encephalopathy, or "mad cow" -- remain mostly a mystery to scientists. ...

Prions show their good side

May 7, 2008

Prions, the infamous agents behind mad cow disease and its human variation, Creutzfeldt-Jakob Disease, also have a helpful side. According to new findings from Gerald Zamponi and colleagues, normally functioning prions prevent ...

Prion discovery gives clue to control of mass gene expression

March 13, 2009

The discovery in common brewer's yeast of a new, infectious, misfolded protein -- or prion -- by University of Illinois at Chicago molecular biologists raises new questions about the roles played by these curious molecules, ...

Prions serve as important source of variation in nature

April 2, 2009

Special proteins known as prions, which are perhaps best known as the agents of mad cow and other neurodegenerative diseases, can also serve as an important source of beneficial variation in nature, confirms a new study in ...

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.

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, ...

Recommended for you

New avenue for understanding cause of common diseases

August 25, 2016

A ground-breaking Auckland study could lead to discoveries about many common diseases such as diabetes, cancer and dementia. The new finding could also illuminate the broader role of the enigmatic mitochondria in human development.

New method creates endless supply of kidney precursor cells

August 25, 2016

Salk Institute scientists have discovered the holy grail of endless youthfulness—at least when it comes to one type of human kidney precursor cell. Previous attempts to maintain cultures of the so-called nephron progenitor ...

Strict diet combats rare progeria aging disorders

August 25, 2016

Mice with a severe aging disease live three times longer if they eat thirty percent less. Moreover, they age much healthier than mice that eat as much as they want. These are findings of a joint study being published today ...

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.