Yeast prions as a model of neurodegenerative infectious amyloidoses in humans

Abstract

Several neurodegenerative diseases (so-called age-related diseases) in humans are associated with development of protein aggregates--amyloids. Prion diseases--kuru, Kreutzfeldt-Jakob and Gerstmann-Straussler-Sheinker diseases, fatal familial insomnia, etc.--are examples of infectious amyloidoses. A model system for investigation of mechanisms of amyloidogenesis and of its infectious nature had been developed as a result of yeast prion discovery. The existence of a prion network as an interaction of different prions identified in yeast is being confirmed recently as an interaction of different anyloids in humans. The potential danger of amyloidoses is conditioned by the very structure of almost all proteins containing fragments capable to be organized as beta-sheets, which lead to their aggregation being exposed. Meanwhile, there are several well-defined examples of the adaptive value of amyloid aggregates: cytoplasmic incompatibility factor in Podospora anserina, spider silk, cytoplasmic stress granules in mammals, prion form of CPEB protein responsible for the neuron activity in Aplisia, etc. These facts should be taken into consideration when seeking antiamyloid drugs. Discovery of protein inheritance in lower eukaryotes modifies our knowledge of the template principle significance in biology and adds a concept of conformational templates (II order templates) involved in reproduction of the three-dimensional structure of the supramolecular complexes in the cell.