Susan Lindquists group at the Whitehead Institute has argued some of the fungal prions are not associated with any disease state, but may have a useful role; however, researchers at the NIH have also provided arguments suggesting that fungal prions could be considered a diseased state. There is evidence that fungal proteins have evolved specific functions that are beneficial to the microorganism that enhance their ability to adapt to their diverse environments.Research into fungal prions has given strong support to the protein-only concept, since purified protein extracted from cells with a prion state has been demonstrated to convert the normal form of the protein into a misfolded form in vitro, and in the process, preserve the information corresponding to different strains of the prion state. It has also shed some light on prion domains, which are regions in a protein that promote the conversion into a prion. Fungal prions have helped to suggest mechanisms of conversion that may apply to all prions, though fungal prions appear distinct from infectious mammalian prions in the lack of cofactor required for propagation. The characteristic prion domains may vary between species – e.g., characteristic fungal prion domains are not found in mammalian prions. Treatments
There are no effective treatments for prion diseases. Clinical trials in humans have not met with success and have been hampered by the rarity of prion diseases. Although some potential treatments have shown promise in the laboratory, none have been effective once the disease has commenced.
With a prion, two protein chains are stabilized if one binds to another in the same conformation. The probability of this happening is low, but once it does the combination of the two is very stable. Then more units can get added, making a sort of "fibril". Prions form abnormal aggregates of proteins called amyloids, which accumulate in infected tissue and are associated with tissue damage and cell death. Amyloids are also responsible for several other neurodegenerative diseases such as Alzheimers disease and Parkinsons disease.A prion disease is a type of proteopathy, or disease of structurally abnormal proteins. In humans, prions are believed to be the cause of Creutzfeldt–Jakob disease (CJD), its variant (vCJD), Gerstmann–Sträussler–Scheinker syndrome (GSS), fatal familial insomnia (FFI), and kuru. There is also evidence suggesting prions may play a part in the process of Alzheimers disease, Parkinsons disease, and amyotrophic lateral sclerosis (ALS); these have been termed prion-like diseases. Several yeast proteins have also been identified as having prionogenic properties, as well as a protein involved in modification of synapses during the formation of memories (see Eric Kandel § Molecular changes during learning). Prion replication is subject to epimutation and natural selection just as for other forms of replication, and their structure varies slightly between species.Prion aggregates are stable, and this structural stability means that prions are resistant to denaturation by chemical and physical agents: they cannot be destroyed by ordinary disinfection or cooking. This makes disposal and containment of these particles difficult.