Related topics: protein

Soil compound fights chronic wasting disease

A major compound in soil organic matter degrades chronic wasting disease prions and decreases infectivity in mice, according to a study published November 29 in the open-access journal PLOS Pathogens by Judd Aiken of the ...

Altering pH bumps prions out of danger zone

Prion diseases are scary, incurable and fatal. They first gained notoriety when cows became infected by prion proteins and, in turn, infected people. Fervor surrounding mad cow disease resulted in the U.S. banning imports ...

Provocative prions may protect yeast cells from stress

Prions have a notorious reputation. They cause neurodegenerative disease, namely mad cow/Creutzfeld-Jakob disease. And the way these protein particles propagate—getting other proteins to join the pile—can seem insidious.

Revising the meaning of 'prion'

A team of Whitehead Institute and Stanford University scientists are redefining what it means to be a prion—a type of protein that can pass heritable traits from cell to cell by its structure instead of by DNA.

Prions can pass on beneficial traits, study finds

Prion proteins, best known as the agents of deadly brain disorders like mad cow disease, can help yeast survive hard times and pass the advantageous traits down to their offspring, according to a new study by researchers ...

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Prion

A prion (pronounced /ˈpriː.ɒn/ ( listen)) is an infectious agent that is composed of protein. To date, all such agents that have been discovered propagate by transmitting a mis-folded protein state; the protein does not itself self-replicate and the process is dependent on the presence of the polypeptide in the host organism. The mis-folded form of the prion protein has been implicated in a number of diseases in a variety of mammals, including bovine spongiform encephalopathy (BSE, also known as "mad cow disease") in cattle and Creutzfeldt-Jakob disease (CJD) in humans. All known prion diseases affect the structure of the brain or other neural tissue, and all are currently untreatable and are always fatal. In general usage, prion refers to the theoretical unit of infection. In scientific notation, PrPC refers to the endogenous form of prion protein (PrP), which is found in a multitude of tissues, while PrPSC refers to the misfolded form of PrP, that is responsible for the formation of amyloid plaques that lead to neurodegeneration.

Prions are hypothesized to infect and propagate by refolding abnormally into a structure which is able to convert normal molecules of the protein into the abnormally structured form. All known prions induce the formation of an amyloid fold, in which the protein polymerises into an aggregate consisting of tightly packed beta sheets. This altered structure is extremely stable and accumulates in infected tissue, causing tissue damage and cell death. This stability means that prions are resistant to denaturation by chemical and physical agents, making disposal and containment of these particles difficult.

Proteins showing prion-type behavior are also found in some fungi and this has been important in helping to understand mammalian prions. However, fungal prions do not appear to cause disease in their hosts and may even confer an evolutionary advantage through a form of protein-based inheritance.

The word prion is a compound word derived from the initial letters of the words proteinaceous and infectious, with -on added by analogy to the word virion.

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